/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//ViewGroup是什么？一个ViewGroup是一个可以包含子View的容器，是布局文件和View容器的基类。在这个类里定义了ViewGroup.LayoutParams类，这个类是布局参数的子类。
//其实ViewGroup也就是VIew的容器，通过ViewGroup.LayoutParams来指定子View的参数。
package android.view;
import android.animation.LayoutTransition;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Insets;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PointF;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Region;
import android.os.Build;
import android.os.Parcelable;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Pools.SynchronizedPool;
import android.util.SparseArray;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityManager;
import android.view.accessibility.AccessibilityNodeInfo;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.LayoutAnimationController;
import android.view.animation.Transformation;
import com.android.internal.R;
import com.android.internal.util.Predicate;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import static android.os.Build.VERSION_CODES.JELLY_BEAN_MR1;
/**
*
* A ViewGroup is a special view that can contain other views
* (called children.) The view group is the base class for layouts and views
* containers. This class also defines the
* {@link android.view.ViewGroup.LayoutParams} class which serves as the base
* class for layouts parameters.
*
*
*
* Also see {@link LayoutParams} for layout attributes.
*
*
*
*
Developer Guides
*
For more information about creating user interface layouts, read the
* XML Layouts developer
* guide.
*
*
Here is a complete implementation of a custom ViewGroup that implements
* a simple {@link android.widget.FrameLayout} along with the ability to stack
* children in left and right gutters.
If you are implementing XML layout attributes as shown in the example, this is the
* corresponding definition for them that would go in res/values/attrs.xml:
Finally the layout manager can be used in an XML layout like so:
*
* {@sample development/samples/ApiDemos/res/layout/custom_layout.xml Complete}
*
* @attr ref android.R.styleable#ViewGroup_clipChildren
* @attr ref android.R.styleable#ViewGroup_clipToPadding
* @attr ref android.R.styleable#ViewGroup_layoutAnimation
* @attr ref android.R.styleable#ViewGroup_animationCache
* @attr ref android.R.styleable#ViewGroup_persistentDrawingCache
* @attr ref android.R.styleable#ViewGroup_alwaysDrawnWithCache
* @attr ref android.R.styleable#ViewGroup_addStatesFromChildren
* @attr ref android.R.styleable#ViewGroup_descendantFocusability
* @attr ref android.R.styleable#ViewGroup_animateLayoutChanges
* @attr ref android.R.styleable#ViewGroup_splitMotionEvents
* @attr ref android.R.styleable#ViewGroup_layoutMode
*/
//ViewGroup作为一个容器，为了制定这个容器应有的标准，所以为其指定了接口
public abstract class ViewGroup extends View implements ViewParent, ViewManager {
private static final String TAG = "ViewGroup";
private static final boolean DBG = false;
/** @hide */
public static boolean DEBUG_DRAW = false;
/**
* Views which have been hidden or removed which need to be animated on
* their way out.
* This field should be made private, so it is hidden from the SDK.
* {@hide}
*/
protected ArrayList mDisappearingChildren;
/**
* Listener used to propagate events indicating when children are added
* and/or removed from a view group.
* This field should be made private, so it is hidden from the SDK.
* {@hide}
*/
protected OnHierarchyChangeListener mOnHierarchyChangeListener;
// The view contained within this ViewGroup that has or contains focus.
private View mFocused;
/**
* A Transformation used when drawing children, to
* apply on the child being drawn.
*/
private Transformation mChildTransformation;
/**
* Used to track the current invalidation region.
*/
RectF mInvalidateRegion;
/**
* A Transformation used to calculate a correct
* invalidation area when the application is autoscaled.
*/
Transformation mInvalidationTransformation;
// View currently under an ongoing drag
private View mCurrentDragView;
// Metadata about the ongoing drag
private DragEvent mCurrentDrag;
private HashSet mDragNotifiedChildren;
// Does this group have a child that can accept the current drag payload?
private boolean mChildAcceptsDrag;
// Used during drag dispatch
private PointF mLocalPoint;
// Layout animation
private LayoutAnimationController mLayoutAnimationController;
private Animation.AnimationListener mAnimationListener;
// First touch target in the linked list of touch targets.
private TouchTarget mFirstTouchTarget;
// For debugging only. You can see these in hierarchyviewer.
@SuppressWarnings({"FieldCanBeLocal", "UnusedDeclaration"})
@ViewDebug.ExportedProperty(category = "events")
private long mLastTouchDownTime;
@ViewDebug.ExportedProperty(category = "events")
private int mLastTouchDownIndex = -1;
@SuppressWarnings({"FieldCanBeLocal", "UnusedDeclaration"})
@ViewDebug.ExportedProperty(category = "events")
private float mLastTouchDownX;
@SuppressWarnings({"FieldCanBeLocal", "UnusedDeclaration"})
@ViewDebug.ExportedProperty(category = "events")
private float mLastTouchDownY;
// First hover target in the linked list of hover targets.
// The hover targets are children which have received ACTION_HOVER_ENTER.
// They might not have actually handled the hover event, but we will
// continue sending hover events to them as long as the pointer remains over
// their bounds and the view group does not intercept hover.
private HoverTarget mFirstHoverTarget;
// True if the view group itself received a hover event.
// It might not have actually handled the hover event.
private boolean mHoveredSelf;
/**
* Internal flags.
*
* This field should be made private, so it is hidden from the SDK.
* {@hide}
*/
@ViewDebug.ExportedProperty(flagMapping = {
@ViewDebug.FlagToString(mask = FLAG_CLIP_CHILDREN, equals = FLAG_CLIP_CHILDREN,
name = "CLIP_CHILDREN"),
@ViewDebug.FlagToString(mask = FLAG_CLIP_TO_PADDING, equals = FLAG_CLIP_TO_PADDING,
name = "CLIP_TO_PADDING"),
@ViewDebug.FlagToString(mask = FLAG_PADDING_NOT_NULL, equals = FLAG_PADDING_NOT_NULL,
name = "PADDING_NOT_NULL")
})
protected int mGroupFlags;
/**
* Either {@link #LAYOUT_MODE_CLIP_BOUNDS} or {@link #LAYOUT_MODE_OPTICAL_BOUNDS}.
*/
private int mLayoutMode = LAYOUT_MODE_UNDEFINED;
/**
* NOTE: If you change the flags below make sure to reflect the changes
* the DisplayList class
*/
// When set, ViewGroup invalidates only the child's rectangle
// Set by default
static final int FLAG_CLIP_CHILDREN = 0x1;
// When set, ViewGroup excludes the padding area from the invalidate rectangle
// Set by default
private static final int FLAG_CLIP_TO_PADDING = 0x2;
// When set, dispatchDraw() will invoke invalidate(); this is set by drawChild() when
// a child needs to be invalidated and FLAG_OPTIMIZE_INVALIDATE is set
static final int FLAG_INVALIDATE_REQUIRED = 0x4;
// When set, dispatchDraw() will run the layout animation and unset the flag
private static final int FLAG_RUN_ANIMATION = 0x8;
// When set, there is either no layout animation on the ViewGroup or the layout
// animation is over
// Set by default
static final int FLAG_ANIMATION_DONE = 0x10;
// If set, this ViewGroup has padding; if unset there is no padding and we don't need
// to clip it, even if FLAG_CLIP_TO_PADDING is set
private static final int FLAG_PADDING_NOT_NULL = 0x20;
// When set, this ViewGroup caches its children in a Bitmap before starting a layout animation
// Set by default
private static final int FLAG_ANIMATION_CACHE = 0x40;
// When set, this ViewGroup converts calls to invalidate(Rect) to invalidate() during a
// layout animation; this avoid clobbering the hierarchy
// Automatically set when the layout animation starts, depending on the animation's
// characteristics
static final int FLAG_OPTIMIZE_INVALIDATE = 0x80;
// When set, the next call to drawChild() will clear mChildTransformation's matrix
static final int FLAG_CLEAR_TRANSFORMATION = 0x100;
// When set, this ViewGroup invokes mAnimationListener.onAnimationEnd() and removes
// the children's Bitmap caches if necessary
// This flag is set when the layout animation is over (after FLAG_ANIMATION_DONE is set)
private static final int FLAG_NOTIFY_ANIMATION_LISTENER = 0x200;
/**
* When set, the drawing method will call {@link #getChildDrawingOrder(int, int)}
* to get the index of the child to draw for that iteration.
*
* @hide
*/
protected static final int FLAG_USE_CHILD_DRAWING_ORDER = 0x400;
/**
* When set, this ViewGroup supports static transformations on children; this causes
* {@link #getChildStaticTransformation(View, android.view.animation.Transformation)} to be
* invoked when a child is drawn.
*
* Any subclass overriding
* {@link #getChildStaticTransformation(View, android.view.animation.Transformation)} should
* set this flags in {@link #mGroupFlags}.
*
* {@hide}
*/
protected static final int FLAG_SUPPORT_STATIC_TRANSFORMATIONS = 0x800;
// When the previous drawChild() invocation used an alpha value that was lower than
// 1.0 and set it in mCachePaint
static final int FLAG_ALPHA_LOWER_THAN_ONE = 0x1000;
/**
* When set, this ViewGroup's drawable states also include those
* of its children.
*/
private static final int FLAG_ADD_STATES_FROM_CHILDREN = 0x2000;
/**
* When set, this ViewGroup tries to always draw its children using their drawing cache.
*/
static final int FLAG_ALWAYS_DRAWN_WITH_CACHE = 0x4000;
/**
* When set, and if FLAG_ALWAYS_DRAWN_WITH_CACHE is not set, this ViewGroup will try to
* draw its children with their drawing cache.
*/
static final int FLAG_CHILDREN_DRAWN_WITH_CACHE = 0x8000;
/**
* When set, this group will go through its list of children to notify them of
* any drawable state change.
*/
private static final int FLAG_NOTIFY_CHILDREN_ON_DRAWABLE_STATE_CHANGE = 0x10000;
private static final int FLAG_MASK_FOCUSABILITY = 0x60000;
/**
* This view will get focus before any of its descendants.
*/
public static final int FOCUS_BEFORE_DESCENDANTS = 0x20000;
/**
* This view will get focus only if none of its descendants want it.
*/
public static final int FOCUS_AFTER_DESCENDANTS = 0x40000;
/**
* This view will block any of its descendants from getting focus, even
* if they are focusable.
*/
public static final int FOCUS_BLOCK_DESCENDANTS = 0x60000;
/**
* Used to map between enum in attrubutes and flag values.
*/
private static final int[] DESCENDANT_FOCUSABILITY_FLAGS =
{FOCUS_BEFORE_DESCENDANTS, FOCUS_AFTER_DESCENDANTS,
FOCUS_BLOCK_DESCENDANTS};
/**
* When set, this ViewGroup should not intercept touch events.
* {@hide}
*/
protected static final int FLAG_DISALLOW_INTERCEPT = 0x80000;
/**
* When set, this ViewGroup will split MotionEvents to multiple child Views when appropriate.
*/
private static final int FLAG_SPLIT_MOTION_EVENTS = 0x200000;
/**
* When set, this ViewGroup will not dispatch onAttachedToWindow calls
* to children when adding new views. This is used to prevent multiple
* onAttached calls when a ViewGroup adds children in its own onAttached method.
*/
private static final int FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW = 0x400000;
/**
* When true, indicates that a layoutMode has been explicitly set, either with
* an explicit call to {@link #setLayoutMode(int)} in code or from an XML resource.
* This distinguishes the situation in which a layout mode was inherited from
* one of the ViewGroup's ancestors and cached locally.
*/
private static final int FLAG_LAYOUT_MODE_WAS_EXPLICITLY_SET = 0x800000;
/**
* Indicates which types of drawing caches are to be kept in memory.
* This field should be made private, so it is hidden from the SDK.
* {@hide}
*/
protected int mPersistentDrawingCache;
/**
* Used to indicate that no drawing cache should be kept in memory.
*/
public static final int PERSISTENT_NO_CACHE = 0x0;
/**
* Used to indicate that the animation drawing cache should be kept in memory.
*/
public static final int PERSISTENT_ANIMATION_CACHE = 0x1;
/**
* Used to indicate that the scrolling drawing cache should be kept in memory.
*/
public static final int PERSISTENT_SCROLLING_CACHE = 0x2;
/**
* Used to indicate that all drawing caches should be kept in memory.
*/
public static final int PERSISTENT_ALL_CACHES = 0x3;
// Layout Modes
private static final int LAYOUT_MODE_UNDEFINED = -1;
/**
* This constant is a {@link #setLayoutMode(int) layoutMode}.
* Clip bounds are the raw values of {@link #getLeft() left}, {@link #getTop() top},
* {@link #getRight() right} and {@link #getBottom() bottom}.
*/
public static final int LAYOUT_MODE_CLIP_BOUNDS = 0;
/**
* This constant is a {@link #setLayoutMode(int) layoutMode}.
* Optical bounds describe where a widget appears to be. They sit inside the clip
* bounds which need to cover a larger area to allow other effects,
* such as shadows and glows, to be drawn.
*/
public static final int LAYOUT_MODE_OPTICAL_BOUNDS = 1;
/** @hide */
public static int LAYOUT_MODE_DEFAULT = LAYOUT_MODE_CLIP_BOUNDS;
/**
* We clip to padding when FLAG_CLIP_TO_PADDING and FLAG_PADDING_NOT_NULL
* are set at the same time.
*/
protected static final int CLIP_TO_PADDING_MASK = FLAG_CLIP_TO_PADDING | FLAG_PADDING_NOT_NULL;
// Index of the child's left position in the mLocation array
private static final int CHILD_LEFT_INDEX = 0;
// Index of the child's top position in the mLocation array
private static final int CHILD_TOP_INDEX = 1;
// Child views of this ViewGroup
//用一个数组来存储这些子View
//由于是通过一个数组来存储View数据的，所以对于ViewGroup来说其必须实现增，删，查的算法。
private View[] mChildren;
// Number of valid children in the mChildren array, the rest should be null or not
// considered as children
private int mChildrenCount;
// Whether layout calls are currently being suppressed, controlled by calls to
// suppressLayout()
boolean mSuppressLayout = false;
// Whether any layout calls have actually been suppressed while mSuppressLayout
// has been true. This tracks whether we need to issue a requestLayout() when
// layout is later re-enabled.
private boolean mLayoutCalledWhileSuppressed = false;
private static final int ARRAY_INITIAL_CAPACITY = 12;
private static final int ARRAY_CAPACITY_INCREMENT = 12;
private static Paint sDebugPaint;
private static float[] sDebugLines;
// Used to draw cached views
Paint mCachePaint;
// Used to animate add/remove changes in layout
private LayoutTransition mTransition;
// The set of views that are currently being transitioned. This list is used to track views
// being removed that should not actually be removed from the parent yet because they are
// being animated.
private ArrayList mTransitioningViews;
// List of children changing visibility. This is used to potentially keep rendering
// views during a transition when they otherwise would have become gone/invisible
private ArrayList mVisibilityChangingChildren;
// Indicates how many of this container's child subtrees contain transient state
@ViewDebug.ExportedProperty(category = "layout")
private int mChildCountWithTransientState = 0;
public ViewGroup(Context context) {
super(context);
initViewGroup();
}
public ViewGroup(Context context, AttributeSet attrs) {
super(context, attrs);
initViewGroup();
initFromAttributes(context, attrs);
}
public ViewGroup(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initViewGroup();
initFromAttributes(context, attrs);
}
private boolean debugDraw() {
return DEBUG_DRAW || mAttachInfo != null && mAttachInfo.mDebugLayout;
}
private void initViewGroup() {
// ViewGroup doesn't draw by default
if (!debugDraw()) {
setFlags(WILL_NOT_DRAW, DRAW_MASK);
}
mGroupFlags |= FLAG_CLIP_CHILDREN;
mGroupFlags |= FLAG_CLIP_TO_PADDING;
mGroupFlags |= FLAG_ANIMATION_DONE;
mGroupFlags |= FLAG_ANIMATION_CACHE;
mGroupFlags |= FLAG_ALWAYS_DRAWN_WITH_CACHE;
if (mContext.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.HONEYCOMB) {
mGroupFlags |= FLAG_SPLIT_MOTION_EVENTS;
}
setDescendantFocusability(FOCUS_BEFORE_DESCENDANTS);
mChildren = new View[ARRAY_INITIAL_CAPACITY];
mChildrenCount = 0;
mPersistentDrawingCache = PERSISTENT_SCROLLING_CACHE;
}
private void initFromAttributes(Context context, AttributeSet attrs) {
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.ViewGroup);
final int N = a.getIndexCount();
for (int i = 0; i < N; i++) {
int attr = a.getIndex(i);
switch (attr) {
case R.styleable.ViewGroup_clipChildren:
setClipChildren(a.getBoolean(attr, true));
break;
case R.styleable.ViewGroup_clipToPadding:
setClipToPadding(a.getBoolean(attr, true));
break;
case R.styleable.ViewGroup_animationCache:
setAnimationCacheEnabled(a.getBoolean(attr, true));
break;
case R.styleable.ViewGroup_persistentDrawingCache:
setPersistentDrawingCache(a.getInt(attr, PERSISTENT_SCROLLING_CACHE));
break;
case R.styleable.ViewGroup_addStatesFromChildren:
setAddStatesFromChildren(a.getBoolean(attr, false));
break;
case R.styleable.ViewGroup_alwaysDrawnWithCache:
setAlwaysDrawnWithCacheEnabled(a.getBoolean(attr, true));
break;
case R.styleable.ViewGroup_layoutAnimation:
int id = a.getResourceId(attr, -1);
if (id > 0) {
setLayoutAnimation(AnimationUtils.loadLayoutAnimation(mContext, id));
}
break;
case R.styleable.ViewGroup_descendantFocusability:
setDescendantFocusability(DESCENDANT_FOCUSABILITY_FLAGS[a.getInt(attr, 0)]);
break;
case R.styleable.ViewGroup_splitMotionEvents:
setMotionEventSplittingEnabled(a.getBoolean(attr, false));
break;
case R.styleable.ViewGroup_animateLayoutChanges:
boolean animateLayoutChanges = a.getBoolean(attr, false);
if (animateLayoutChanges) {
setLayoutTransition(new LayoutTransition());
}
break;
case R.styleable.ViewGroup_layoutMode:
setLayoutMode(a.getInt(attr, LAYOUT_MODE_UNDEFINED));
break;
}
}
a.recycle();
}
/**
* Gets the descendant focusability of this view group. The descendant
* focusability defines the relationship between this view group and its
* descendants when looking for a view to take focus in
* {@link #requestFocus(int, android.graphics.Rect)}.
*
* @return one of {@link #FOCUS_BEFORE_DESCENDANTS}, {@link #FOCUS_AFTER_DESCENDANTS},
* {@link #FOCUS_BLOCK_DESCENDANTS}.
*/
@ViewDebug.ExportedProperty(category = "focus", mapping = {
@ViewDebug.IntToString(from = FOCUS_BEFORE_DESCENDANTS, to = "FOCUS_BEFORE_DESCENDANTS"),
@ViewDebug.IntToString(from = FOCUS_AFTER_DESCENDANTS, to = "FOCUS_AFTER_DESCENDANTS"),
@ViewDebug.IntToString(from = FOCUS_BLOCK_DESCENDANTS, to = "FOCUS_BLOCK_DESCENDANTS")
})
public int getDescendantFocusability() {
return mGroupFlags & FLAG_MASK_FOCUSABILITY;
}
/**
* Set the descendant focusability of this view group. This defines the relationship
* between this view group and its descendants when looking for a view to
* take focus in {@link #requestFocus(int, android.graphics.Rect)}.
*
* @param focusability one of {@link #FOCUS_BEFORE_DESCENDANTS}, {@link #FOCUS_AFTER_DESCENDANTS},
* {@link #FOCUS_BLOCK_DESCENDANTS}.
*/
public void setDescendantFocusability(int focusability) {
switch (focusability) {
case FOCUS_BEFORE_DESCENDANTS:
case FOCUS_AFTER_DESCENDANTS:
case FOCUS_BLOCK_DESCENDANTS:
break;
default:
throw new IllegalArgumentException("must be one of FOCUS_BEFORE_DESCENDANTS, "
+ "FOCUS_AFTER_DESCENDANTS, FOCUS_BLOCK_DESCENDANTS");
}
mGroupFlags &= ~FLAG_MASK_FOCUSABILITY;
mGroupFlags |= (focusability & FLAG_MASK_FOCUSABILITY);
}
/**
* {@inheritDoc}
*/
@Override
void handleFocusGainInternal(int direction, Rect previouslyFocusedRect) {
if (mFocused != null) {
mFocused.unFocus();
mFocused = null;
}
super.handleFocusGainInternal(direction, previouslyFocusedRect);
}
/**
* {@inheritDoc}
*/
public void requestChildFocus(View child, View focused) {
if (DBG) {
System.out.println(this + " requestChildFocus()");
}
if (getDescendantFocusability() == FOCUS_BLOCK_DESCENDANTS) {
return;
}
// Unfocus us, if necessary
super.unFocus();
// We had a previous notion of who had focus. Clear it.
if (mFocused != child) {
if (mFocused != null) {
mFocused.unFocus();
}
mFocused = child;
}
if (mParent != null) {
mParent.requestChildFocus(this, focused);
}
}
/**
* {@inheritDoc}
*/
public void focusableViewAvailable(View v) {
if (mParent != null
// shortcut: don't report a new focusable view if we block our descendants from
// getting focus
&& (getDescendantFocusability() != FOCUS_BLOCK_DESCENDANTS)
// shortcut: don't report a new focusable view if we already are focused
// (and we don't prefer our descendants)
//
// note: knowing that mFocused is non-null is not a good enough reason
// to break the traversal since in that case we'd actually have to find
// the focused view and make sure it wasn't FOCUS_AFTER_DESCENDANTS and
// an ancestor of v; this will get checked for at ViewAncestor
&& !(isFocused() && getDescendantFocusability() != FOCUS_AFTER_DESCENDANTS)) {
mParent.focusableViewAvailable(v);
}
}
/**
* {@inheritDoc}
*/
public boolean showContextMenuForChild(View originalView) {
return mParent != null && mParent.showContextMenuForChild(originalView);
}
/**
* {@inheritDoc}
*/
public ActionMode startActionModeForChild(View originalView, ActionMode.Callback callback) {
return mParent != null ? mParent.startActionModeForChild(originalView, callback) : null;
}
/**
* Find the nearest view in the specified direction that wants to take
* focus.
*
* @param focused The view that currently has focus
* @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and
* FOCUS_RIGHT, or 0 for not applicable.
*/
public View focusSearch(View focused, int direction) {
if (isRootNamespace()) {
// root namespace means we should consider ourselves the top of the
// tree for focus searching; otherwise we could be focus searching
// into other tabs. see LocalActivityManager and TabHost for more info
return FocusFinder.getInstance().findNextFocus(this, focused, direction);
} else if (mParent != null) {
return mParent.focusSearch(focused, direction);
}
return null;
}
/**
* {@inheritDoc}
*/
public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) {
return false;
}
/**
* {@inheritDoc}
*/
@Override
public boolean requestSendAccessibilityEvent(View child, AccessibilityEvent event) {
ViewParent parent = mParent;
if (parent == null) {
return false;
}
final boolean propagate = onRequestSendAccessibilityEvent(child, event);
if (!propagate) {
return false;
}
return parent.requestSendAccessibilityEvent(this, event);
}
/**
* Called when a child has requested sending an {@link AccessibilityEvent} and
* gives an opportunity to its parent to augment the event.
*
* If an {@link android.view.View.AccessibilityDelegate} has been specified via calling
* {@link android.view.View#setAccessibilityDelegate(android.view.View.AccessibilityDelegate)} its
* {@link android.view.View.AccessibilityDelegate#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent)}
* is responsible for handling this call.
*
*
* @param child The child which requests sending the event.
* @param event The event to be sent.
* @return True if the event should be sent.
*
* @see #requestSendAccessibilityEvent(View, AccessibilityEvent)
*/
public boolean onRequestSendAccessibilityEvent(View child, AccessibilityEvent event) {
if (mAccessibilityDelegate != null) {
return mAccessibilityDelegate.onRequestSendAccessibilityEvent(this, child, event);
} else {
return onRequestSendAccessibilityEventInternal(child, event);
}
}
/**
* @see #onRequestSendAccessibilityEvent(View, AccessibilityEvent)
*
* Note: Called from the default {@link View.AccessibilityDelegate}.
*/
boolean onRequestSendAccessibilityEventInternal(View child, AccessibilityEvent event) {
return true;
}
/**
* Called when a child view has changed whether or not it is tracking transient state.
*/
public void childHasTransientStateChanged(View child, boolean childHasTransientState) {
final boolean oldHasTransientState = hasTransientState();
if (childHasTransientState) {
mChildCountWithTransientState++;
} else {
mChildCountWithTransientState--;
}
final boolean newHasTransientState = hasTransientState();
if (mParent != null && oldHasTransientState != newHasTransientState) {
try {
mParent.childHasTransientStateChanged(this, newHasTransientState);
} catch (AbstractMethodError e) {
Log.e(TAG, mParent.getClass().getSimpleName() +
" does not fully implement ViewParent", e);
}
}
}
@Override
public boolean hasTransientState() {
return mChildCountWithTransientState > 0 || super.hasTransientState();
}
/**
* {@inheritDoc}
*/
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
return mFocused != null &&
mFocused.dispatchUnhandledMove(focused, direction);
}
/**
* {@inheritDoc}
*/
public void clearChildFocus(View child) {
if (DBG) {
System.out.println(this + " clearChildFocus()");
}
mFocused = null;
if (mParent != null) {
mParent.clearChildFocus(this);
}
}
/**
* {@inheritDoc}
*/
@Override
public void clearFocus() {
if (DBG) {
System.out.println(this + " clearFocus()");
}
if (mFocused == null) {
super.clearFocus();
} else {
View focused = mFocused;
mFocused = null;
focused.clearFocus();
}
}
/**
* {@inheritDoc}
*/
@Override
void unFocus() {
if (DBG) {
System.out.println(this + " unFocus()");
}
if (mFocused == null) {
super.unFocus();
} else {
mFocused.unFocus();
mFocused = null;
}
}
/**
* Returns the focused child of this view, if any. The child may have focus
* or contain focus.
*
* @return the focused child or null.
*/
public View getFocusedChild() {
return mFocused;
}
/**
* Returns true if this view has or contains focus
*
* @return true if this view has or contains focus
*/
@Override
public boolean hasFocus() {
return (mPrivateFlags & PFLAG_FOCUSED) != 0 || mFocused != null;
}
/*
* (non-Javadoc)
*
* @see android.view.View#findFocus()
*/
@Override
public View findFocus() {
if (DBG) {
System.out.println("Find focus in " + this + ": flags="
+ isFocused() + ", child=" + mFocused);
}
if (isFocused()) {
return this;
}
if (mFocused != null) {
return mFocused.findFocus();
}
return null;
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasFocusable() {
if ((mViewFlags & VISIBILITY_MASK) != VISIBLE) {
return false;
}
if (isFocusable()) {
return true;
}
final int descendantFocusability = getDescendantFocusability();
if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
if (child.hasFocusable()) {
return true;
}
}
}
return false;
}
/**
* {@inheritDoc}
*/
@Override
public void addFocusables(ArrayList views, int direction, int focusableMode) {
final int focusableCount = views.size();
final int descendantFocusability = getDescendantFocusability();
if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
child.addFocusables(views, direction, focusableMode);
}
}
}
// we add ourselves (if focusable) in all cases except for when we are
// FOCUS_AFTER_DESCENDANTS and there are some descendants focusable. this is
// to avoid the focus search finding layouts when a more precise search
// among the focusable children would be more interesting.
if (descendantFocusability != FOCUS_AFTER_DESCENDANTS
// No focusable descendants
|| (focusableCount == views.size())) {
super.addFocusables(views, direction, focusableMode);
}
}
@Override
public void findViewsWithText(ArrayList outViews, CharSequence text, int flags) {
super.findViewsWithText(outViews, text, flags);
final int childrenCount = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < childrenCount; i++) {
View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE
&& (child.mPrivateFlags & PFLAG_IS_ROOT_NAMESPACE) == 0) {
child.findViewsWithText(outViews, text, flags);
}
}
}
/** @hide */
@Override
public View findViewByAccessibilityIdTraversal(int accessibilityId) {
View foundView = super.findViewByAccessibilityIdTraversal(accessibilityId);
if (foundView != null) {
return foundView;
}
final int childrenCount = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < childrenCount; i++) {
View child = children[i];
foundView = child.findViewByAccessibilityIdTraversal(accessibilityId);
if (foundView != null) {
return foundView;
}
}
return null;
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchWindowFocusChanged(boolean hasFocus) {
super.dispatchWindowFocusChanged(hasFocus);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchWindowFocusChanged(hasFocus);
}
}
/**
* {@inheritDoc}
*/
@Override
public void addTouchables(ArrayList views) {
super.addTouchables(views);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
child.addTouchables(views);
}
}
}
/**
* @hide
*/
@Override
public void makeOptionalFitsSystemWindows() {
super.makeOptionalFitsSystemWindows();
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].makeOptionalFitsSystemWindows();
}
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchDisplayHint(int hint) {
super.dispatchDisplayHint(hint);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchDisplayHint(hint);
}
}
/**
* Called when a view's visibility has changed. Notify the parent to take any appropriate
* action.
*
* @param child The view whose visibility has changed
* @param oldVisibility The previous visibility value (GONE, INVISIBLE, or VISIBLE).
* @param newVisibility The new visibility value (GONE, INVISIBLE, or VISIBLE).
* @hide
*/
protected void onChildVisibilityChanged(View child, int oldVisibility, int newVisibility) {
if (mTransition != null) {
if (newVisibility == VISIBLE) {
mTransition.showChild(this, child, oldVisibility);
} else {
mTransition.hideChild(this, child, newVisibility);
if (mTransitioningViews != null && mTransitioningViews.contains(child)) {
// Only track this on disappearing views - appearing views are already visible
// and don't need special handling during drawChild()
if (mVisibilityChangingChildren == null) {
mVisibilityChangingChildren = new ArrayList();
}
mVisibilityChangingChildren.add(child);
addDisappearingView(child);
}
}
}
// in all cases, for drags
if (mCurrentDrag != null) {
if (newVisibility == VISIBLE) {
notifyChildOfDrag(child);
}
}
}
/**
* {@inheritDoc}
*/
@Override
protected void dispatchVisibilityChanged(View changedView, int visibility) {
super.dispatchVisibilityChanged(changedView, visibility);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchVisibilityChanged(changedView, visibility);
}
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchWindowVisibilityChanged(int visibility) {
super.dispatchWindowVisibilityChanged(visibility);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchWindowVisibilityChanged(visibility);
}
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchConfigurationChanged(Configuration newConfig) {
super.dispatchConfigurationChanged(newConfig);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchConfigurationChanged(newConfig);
}
}
/**
* {@inheritDoc}
*/
public void recomputeViewAttributes(View child) {
if (mAttachInfo != null && !mAttachInfo.mRecomputeGlobalAttributes) {
ViewParent parent = mParent;
if (parent != null) parent.recomputeViewAttributes(this);
}
}
@Override
void dispatchCollectViewAttributes(AttachInfo attachInfo, int visibility) {
if ((visibility & VISIBILITY_MASK) == VISIBLE) {
super.dispatchCollectViewAttributes(attachInfo, visibility);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
child.dispatchCollectViewAttributes(attachInfo,
visibility | (child.mViewFlags&VISIBILITY_MASK));
}
}
}
/**
* {@inheritDoc}
*/
public void bringChildToFront(View child) {
int index = indexOfChild(child);
if (index >= 0) {
removeFromArray(index);
addInArray(child, mChildrenCount);
child.mParent = this;
requestLayout();
invalidate();
}
}
private PointF getLocalPoint() {
if (mLocalPoint == null) mLocalPoint = new PointF();
return mLocalPoint;
}
/**
* {@inheritDoc}
*/
// TODO: Write real docs
@Override
public boolean dispatchDragEvent(DragEvent event) {
boolean retval = false;
final float tx = event.mX;
final float ty = event.mY;
ViewRootImpl root = getViewRootImpl();
// Dispatch down the view hierarchy
final PointF localPoint = getLocalPoint();
switch (event.mAction) {
case DragEvent.ACTION_DRAG_STARTED: {
// clear state to recalculate which views we drag over
mCurrentDragView = null;
// Set up our tracking of drag-started notifications
mCurrentDrag = DragEvent.obtain(event);
if (mDragNotifiedChildren == null) {
mDragNotifiedChildren = new HashSet();
} else {
mDragNotifiedChildren.clear();
}
// Now dispatch down to our children, caching the responses
mChildAcceptsDrag = false;
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
child.mPrivateFlags2 &= ~View.DRAG_MASK;
if (child.getVisibility() == VISIBLE) {
final boolean handled = notifyChildOfDrag(children[i]);
if (handled) {
mChildAcceptsDrag = true;
}
}
}
// Return HANDLED if one of our children can accept the drag
if (mChildAcceptsDrag) {
retval = true;
}
} break;
case DragEvent.ACTION_DRAG_ENDED: {
// Release the bookkeeping now that the drag lifecycle has ended
if (mDragNotifiedChildren != null) {
for (View child : mDragNotifiedChildren) {
// If a child was notified about an ongoing drag, it's told that it's over
child.dispatchDragEvent(event);
child.mPrivateFlags2 &= ~View.DRAG_MASK;
child.refreshDrawableState();
}
mDragNotifiedChildren.clear();
if (mCurrentDrag != null) {
mCurrentDrag.recycle();
mCurrentDrag = null;
}
}
// We consider drag-ended to have been handled if one of our children
// had offered to handle the drag.
if (mChildAcceptsDrag) {
retval = true;
}
} break;
case DragEvent.ACTION_DRAG_LOCATION: {
// Find the [possibly new] drag target
final View target = findFrontmostDroppableChildAt(event.mX, event.mY, localPoint);
// If we've changed apparent drag target, tell the view root which view
// we're over now [for purposes of the eventual drag-recipient-changed
// notifications to the framework] and tell the new target that the drag
// has entered its bounds. The root will see setDragFocus() calls all
// the way down to the final leaf view that is handling the LOCATION event
// before reporting the new potential recipient to the framework.
if (mCurrentDragView != target) {
root.setDragFocus(target);
final int action = event.mAction;
// If we've dragged off of a child view, send it the EXITED message
if (mCurrentDragView != null) {
final View view = mCurrentDragView;
event.mAction = DragEvent.ACTION_DRAG_EXITED;
view.dispatchDragEvent(event);
view.mPrivateFlags2 &= ~View.PFLAG2_DRAG_HOVERED;
view.refreshDrawableState();
}
mCurrentDragView = target;
// If we've dragged over a new child view, send it the ENTERED message
if (target != null) {
event.mAction = DragEvent.ACTION_DRAG_ENTERED;
target.dispatchDragEvent(event);
target.mPrivateFlags2 |= View.PFLAG2_DRAG_HOVERED;
target.refreshDrawableState();
}
event.mAction = action; // restore the event's original state
}
// Dispatch the actual drag location notice, localized into its coordinates
if (target != null) {
event.mX = localPoint.x;
event.mY = localPoint.y;
retval = target.dispatchDragEvent(event);
event.mX = tx;
event.mY = ty;
}
} break;
/* Entered / exited dispatch
*
* DRAG_ENTERED is not dispatched downwards from ViewGroup. The reason for this is
* that we're about to get the corresponding LOCATION event, which we will use to
* determine which of our children is the new target; at that point we will
* push a DRAG_ENTERED down to the new target child [which may itself be a ViewGroup].
*
* DRAG_EXITED *is* dispatched all the way down immediately: once we know the
* drag has left this ViewGroup, we know by definition that every contained subview
* is also no longer under the drag point.
*/
case DragEvent.ACTION_DRAG_EXITED: {
if (mCurrentDragView != null) {
final View view = mCurrentDragView;
view.dispatchDragEvent(event);
view.mPrivateFlags2 &= ~View.PFLAG2_DRAG_HOVERED;
view.refreshDrawableState();
mCurrentDragView = null;
}
} break;
case DragEvent.ACTION_DROP: {
if (ViewDebug.DEBUG_DRAG) Log.d(View.VIEW_LOG_TAG, "Drop event: " + event);
View target = findFrontmostDroppableChildAt(event.mX, event.mY, localPoint);
if (target != null) {
if (ViewDebug.DEBUG_DRAG) Log.d(View.VIEW_LOG_TAG, " dispatch drop to " + target);
event.mX = localPoint.x;
event.mY = localPoint.y;
retval = target.dispatchDragEvent(event);
event.mX = tx;
event.mY = ty;
} else {
if (ViewDebug.DEBUG_DRAG) {
Log.d(View.VIEW_LOG_TAG, " not dropped on an accepting view");
}
}
} break;
}
// If none of our children could handle the event, try here
if (!retval) {
// Call up to the View implementation that dispatches to installed listeners
retval = super.dispatchDragEvent(event);
}
return retval;
}
// Find the frontmost child view that lies under the given point, and calculate
// the position within its own local coordinate system.
View findFrontmostDroppableChildAt(float x, float y, PointF outLocalPoint) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = count - 1; i >= 0; i--) {
final View child = children[i];
if (!child.canAcceptDrag()) {
continue;
}
if (isTransformedTouchPointInView(x, y, child, outLocalPoint)) {
return child;
}
}
return null;
}
boolean notifyChildOfDrag(View child) {
if (ViewDebug.DEBUG_DRAG) {
Log.d(View.VIEW_LOG_TAG, "Sending drag-started to view: " + child);
}
boolean canAccept = false;
if (! mDragNotifiedChildren.contains(child)) {
mDragNotifiedChildren.add(child);
canAccept = child.dispatchDragEvent(mCurrentDrag);
if (canAccept && !child.canAcceptDrag()) {
child.mPrivateFlags2 |= View.PFLAG2_DRAG_CAN_ACCEPT;
child.refreshDrawableState();
}
}
return canAccept;
}
@Override
public void dispatchWindowSystemUiVisiblityChanged(int visible) {
super.dispatchWindowSystemUiVisiblityChanged(visible);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i=0; i = 0; i--) {
final int childIndex = customChildOrder
? getChildDrawingOrder(childrenCount, i) : i;
final View child = children[childIndex];
if (!canViewReceivePointerEvents(child)
|| !isTransformedTouchPointInView(x, y, child, null)) {
continue;
}
// Obtain a hover target for this child. Dequeue it from the
// old hover target list if the child was previously hovered.
HoverTarget hoverTarget = firstOldHoverTarget;
final boolean wasHovered;
for (HoverTarget predecessor = null; ;) {
if (hoverTarget == null) {
hoverTarget = HoverTarget.obtain(child);
wasHovered = false;
break;
}
if (hoverTarget.child == child) {
if (predecessor != null) {
predecessor.next = hoverTarget.next;
} else {
firstOldHoverTarget = hoverTarget.next;
}
hoverTarget.next = null;
wasHovered = true;
break;
}
predecessor = hoverTarget;
hoverTarget = hoverTarget.next;
}
// Enqueue the hover target onto the new hover target list.
if (lastHoverTarget != null) {
lastHoverTarget.next = hoverTarget;
} else {
mFirstHoverTarget = hoverTarget;
}
lastHoverTarget = hoverTarget;
// Dispatch the event to the child.
if (action == MotionEvent.ACTION_HOVER_ENTER) {
if (!wasHovered) {
// Send the enter as is.
handled |= dispatchTransformedGenericPointerEvent(
event, child); // enter
}
} else if (action == MotionEvent.ACTION_HOVER_MOVE) {
if (!wasHovered) {
// Synthesize an enter from a move.
eventNoHistory = obtainMotionEventNoHistoryOrSelf(eventNoHistory);
eventNoHistory.setAction(MotionEvent.ACTION_HOVER_ENTER);
handled |= dispatchTransformedGenericPointerEvent(
eventNoHistory, child); // enter
eventNoHistory.setAction(action);
handled |= dispatchTransformedGenericPointerEvent(
eventNoHistory, child); // move
} else {
// Send the move as is.
handled |= dispatchTransformedGenericPointerEvent(event, child);
}
}
if (handled) {
break;
}
}
}
}
// Send exit events to all previously hovered children that are no longer hovered.
while (firstOldHoverTarget != null) {
final View child = firstOldHoverTarget.child;
// Exit the old hovered child.
if (action == MotionEvent.ACTION_HOVER_EXIT) {
// Send the exit as is.
handled |= dispatchTransformedGenericPointerEvent(
event, child); // exit
} else {
// Synthesize an exit from a move or enter.
// Ignore the result because hover focus has moved to a different view.
if (action == MotionEvent.ACTION_HOVER_MOVE) {
dispatchTransformedGenericPointerEvent(
event, child); // move
}
eventNoHistory = obtainMotionEventNoHistoryOrSelf(eventNoHistory);
eventNoHistory.setAction(MotionEvent.ACTION_HOVER_EXIT);
dispatchTransformedGenericPointerEvent(
eventNoHistory, child); // exit
eventNoHistory.setAction(action);
}
final HoverTarget nextOldHoverTarget = firstOldHoverTarget.next;
firstOldHoverTarget.recycle();
firstOldHoverTarget = nextOldHoverTarget;
}
// Send events to the view group itself if no children have handled it.
boolean newHoveredSelf = !handled;
if (newHoveredSelf == mHoveredSelf) {
if (newHoveredSelf) {
// Send event to the view group as before.
handled |= super.dispatchHoverEvent(event);
}
} else {
if (mHoveredSelf) {
// Exit the view group.
if (action == MotionEvent.ACTION_HOVER_EXIT) {
// Send the exit as is.
handled |= super.dispatchHoverEvent(event); // exit
} else {
// Synthesize an exit from a move or enter.
// Ignore the result because hover focus is moving to a different view.
if (action == MotionEvent.ACTION_HOVER_MOVE) {
super.dispatchHoverEvent(event); // move
}
eventNoHistory = obtainMotionEventNoHistoryOrSelf(eventNoHistory);
eventNoHistory.setAction(MotionEvent.ACTION_HOVER_EXIT);
super.dispatchHoverEvent(eventNoHistory); // exit
eventNoHistory.setAction(action);
}
mHoveredSelf = false;
}
if (newHoveredSelf) {
// Enter the view group.
if (action == MotionEvent.ACTION_HOVER_ENTER) {
// Send the enter as is.
handled |= super.dispatchHoverEvent(event); // enter
mHoveredSelf = true;
} else if (action == MotionEvent.ACTION_HOVER_MOVE) {
// Synthesize an enter from a move.
eventNoHistory = obtainMotionEventNoHistoryOrSelf(eventNoHistory);
eventNoHistory.setAction(MotionEvent.ACTION_HOVER_ENTER);
handled |= super.dispatchHoverEvent(eventNoHistory); // enter
eventNoHistory.setAction(action);
handled |= super.dispatchHoverEvent(eventNoHistory); // move
mHoveredSelf = true;
}
}
}
// Recycle the copy of the event that we made.
if (eventNoHistory != event) {
eventNoHistory.recycle();
}
// Done.
return handled;
}
private void exitHoverTargets() {
if (mHoveredSelf || mFirstHoverTarget != null) {
final long now = SystemClock.uptimeMillis();
MotionEvent event = MotionEvent.obtain(now, now,
MotionEvent.ACTION_HOVER_EXIT, 0.0f, 0.0f, 0);
event.setSource(InputDevice.SOURCE_TOUCHSCREEN);
dispatchHoverEvent(event);
event.recycle();
}
}
private void cancelHoverTarget(View view) {
HoverTarget predecessor = null;
HoverTarget target = mFirstHoverTarget;
while (target != null) {
final HoverTarget next = target.next;
if (target.child == view) {
if (predecessor == null) {
mFirstHoverTarget = next;
} else {
predecessor.next = next;
}
target.recycle();
final long now = SystemClock.uptimeMillis();
MotionEvent event = MotionEvent.obtain(now, now,
MotionEvent.ACTION_HOVER_EXIT, 0.0f, 0.0f, 0);
event.setSource(InputDevice.SOURCE_TOUCHSCREEN);
view.dispatchHoverEvent(event);
event.recycle();
return;
}
predecessor = target;
target = next;
}
}
/** @hide */
@Override
protected boolean hasHoveredChild() {
return mFirstHoverTarget != null;
}
@Override
public void addChildrenForAccessibility(ArrayList childrenForAccessibility) {
ChildListForAccessibility children = ChildListForAccessibility.obtain(this, true);
try {
final int childrenCount = children.getChildCount();
for (int i = 0; i < childrenCount; i++) {
View child = children.getChildAt(i);
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
if (child.includeForAccessibility()) {
childrenForAccessibility.add(child);
} else {
child.addChildrenForAccessibility(childrenForAccessibility);
}
}
}
} finally {
children.recycle();
}
}
/**
* Implement this method to intercept hover events before they are handled
* by child views.
*
* This method is called before dispatching a hover event to a child of
* the view group or to the view group's own {@link #onHoverEvent} to allow
* the view group a chance to intercept the hover event.
* This method can also be used to watch all pointer motions that occur within
* the bounds of the view group even when the pointer is hovering over
* a child of the view group rather than over the view group itself.
*
* The view group can prevent its children from receiving hover events by
* implementing this method and returning true to indicate
* that it would like to intercept hover events. The view group must
* continuously return true from {@link #onInterceptHoverEvent}
* for as long as it wishes to continue intercepting hover events from
* its children.
*
* Interception preserves the invariant that at most one view can be
* hovered at a time by transferring hover focus from the currently hovered
* child to the view group or vice-versa as needed.
*
* If this method returns true and a child is already hovered, then the
* child view will first receive a hover exit event and then the view group
* itself will receive a hover enter event in {@link #onHoverEvent}.
* Likewise, if this method had previously returned true to intercept hover
* events and instead returns false while the pointer is hovering
* within the bounds of one of a child, then the view group will first receive a
* hover exit event in {@link #onHoverEvent} and then the hovered child will
* receive a hover enter event.
*
* The default implementation always returns false.
*
*
* @param event The motion event that describes the hover.
* @return True if the view group would like to intercept the hover event
* and prevent its children from receiving it.
*/
public boolean onInterceptHoverEvent(MotionEvent event) {
return false;
}
private static MotionEvent obtainMotionEventNoHistoryOrSelf(MotionEvent event) {
if (event.getHistorySize() == 0) {
return event;
}
return MotionEvent.obtainNoHistory(event);
}
/**
* {@inheritDoc}
*/
@Override
protected boolean dispatchGenericPointerEvent(MotionEvent event) {
// Send the event to the child under the pointer.
final int childrenCount = mChildrenCount;
if (childrenCount != 0) {
final View[] children = mChildren;
final float x = event.getX();
final float y = event.getY();
final boolean customOrder = isChildrenDrawingOrderEnabled();
for (int i = childrenCount - 1; i >= 0; i--) {
final int childIndex = customOrder ? getChildDrawingOrder(childrenCount, i) : i;
final View child = children[childIndex];
if (!canViewReceivePointerEvents(child)
|| !isTransformedTouchPointInView(x, y, child, null)) {
continue;
}
if (dispatchTransformedGenericPointerEvent(event, child)) {
return true;
}
}
}
// No child handled the event. Send it to this view group.
return super.dispatchGenericPointerEvent(event);
}
/**
* {@inheritDoc}
*/
@Override
protected boolean dispatchGenericFocusedEvent(MotionEvent event) {
// Send the event to the focused child or to this view group if it has focus.
if ((mPrivateFlags & (PFLAG_FOCUSED | PFLAG_HAS_BOUNDS))
== (PFLAG_FOCUSED | PFLAG_HAS_BOUNDS)) {
return super.dispatchGenericFocusedEvent(event);
} else if (mFocused != null && (mFocused.mPrivateFlags & PFLAG_HAS_BOUNDS)
== PFLAG_HAS_BOUNDS) {
return mFocused.dispatchGenericMotionEvent(event);
}
return false;
}
/**
* Dispatches a generic pointer event to a child, taking into account
* transformations that apply to the child.
*
* @param event The event to send.
* @param child The view to send the event to.
* @return {@code true} if the child handled the event.
*/
private boolean dispatchTransformedGenericPointerEvent(MotionEvent event, View child) {
final float offsetX = mScrollX - child.mLeft;
final float offsetY = mScrollY - child.mTop;
boolean handled;
if (!child.hasIdentityMatrix()) {
MotionEvent transformedEvent = MotionEvent.obtain(event);
transformedEvent.offsetLocation(offsetX, offsetY);
transformedEvent.transform(child.getInverseMatrix());
handled = child.dispatchGenericMotionEvent(transformedEvent);
transformedEvent.recycle();
} else {
event.offsetLocation(offsetX, offsetY);
handled = child.dispatchGenericMotionEvent(event);
event.offsetLocation(-offsetX, -offsetY);
}
return handled;
}
/**
* {@inheritDoc}
*/
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onTouchEvent(ev, 1);
}
boolean handled = false;
if (onFilterTouchEventForSecurity(ev)) {
final int action = ev.getAction();
final int actionMasked = action & MotionEvent.ACTION_MASK;
// Handle an initial down.
if (actionMasked == MotionEvent.ACTION_DOWN) {
// Throw away all previous state when starting a new touch gesture.
// The framework may have dropped the up or cancel event for the previous gesture
// due to an app switch, ANR, or some other state change.
cancelAndClearTouchTargets(ev);
resetTouchState();
}
// Check for interception.
final boolean intercepted;
if (actionMasked == MotionEvent.ACTION_DOWN
|| mFirstTouchTarget != null) {
final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;
if (!disallowIntercept) {
intercepted = onInterceptTouchEvent(ev);
ev.setAction(action); // restore action in case it was changed
} else {
intercepted = false;
}
} else {
// There are no touch targets and this action is not an initial down
// so this view group continues to intercept touches.
intercepted = true;
}
// Check for cancelation.
final boolean canceled = resetCancelNextUpFlag(this)
|| actionMasked == MotionEvent.ACTION_CANCEL;
// Update list of touch targets for pointer down, if needed.
final boolean split = (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) != 0;
TouchTarget newTouchTarget = null;
boolean alreadyDispatchedToNewTouchTarget = false;
if (!canceled && !intercepted) {
if (actionMasked == MotionEvent.ACTION_DOWN
|| (split && actionMasked == MotionEvent.ACTION_POINTER_DOWN)
|| actionMasked == MotionEvent.ACTION_HOVER_MOVE) {
final int actionIndex = ev.getActionIndex(); // always 0 for down
final int idBitsToAssign = split ? 1 << ev.getPointerId(actionIndex)
: TouchTarget.ALL_POINTER_IDS;
// Clean up earlier touch targets for this pointer id in case they
// have become out of sync.
removePointersFromTouchTargets(idBitsToAssign);
final int childrenCount = mChildrenCount;
if (newTouchTarget == null && childrenCount != 0) {
final float x = ev.getX(actionIndex);
final float y = ev.getY(actionIndex);
// Find a child that can receive the event.
// Scan children from front to back.
final View[] children = mChildren;
final boolean customOrder = isChildrenDrawingOrderEnabled();
for (int i = childrenCount - 1; i >= 0; i--) {
final int childIndex = customOrder ?
getChildDrawingOrder(childrenCount, i) : i;
final View child = children[childIndex];
if (!canViewReceivePointerEvents(child)
|| !isTransformedTouchPointInView(x, y, child, null)) {
continue;
}
newTouchTarget = getTouchTarget(child);
if (newTouchTarget != null) {
// Child is already receiving touch within its bounds.
// Give it the new pointer in addition to the ones it is handling.
newTouchTarget.pointerIdBits |= idBitsToAssign;
break;
}
resetCancelNextUpFlag(child);
if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) {
// Child wants to receive touch within its bounds.
mLastTouchDownTime = ev.getDownTime();
mLastTouchDownIndex = childIndex;
mLastTouchDownX = ev.getX();
mLastTouchDownY = ev.getY();
newTouchTarget = addTouchTarget(child, idBitsToAssign);
alreadyDispatchedToNewTouchTarget = true;
break;
}
}
}
if (newTouchTarget == null && mFirstTouchTarget != null) {
// Did not find a child to receive the event.
// Assign the pointer to the least recently added target.
newTouchTarget = mFirstTouchTarget;
while (newTouchTarget.next != null) {
newTouchTarget = newTouchTarget.next;
}
newTouchTarget.pointerIdBits |= idBitsToAssign;
}
}
}
// Dispatch to touch targets.
if (mFirstTouchTarget == null) {
// No touch targets so treat this as an ordinary view.
handled = dispatchTransformedTouchEvent(ev, canceled, null,
TouchTarget.ALL_POINTER_IDS);
} else {
// Dispatch to touch targets, excluding the new touch target if we already
// dispatched to it. Cancel touch targets if necessary.
TouchTarget predecessor = null;
TouchTarget target = mFirstTouchTarget;
while (target != null) {
final TouchTarget next = target.next;
if (alreadyDispatchedToNewTouchTarget && target == newTouchTarget) {
handled = true;
} else {
final boolean cancelChild = resetCancelNextUpFlag(target.child)
|| intercepted;
if (dispatchTransformedTouchEvent(ev, cancelChild,
target.child, target.pointerIdBits)) {
handled = true;
}
if (cancelChild) {
if (predecessor == null) {
mFirstTouchTarget = next;
} else {
predecessor.next = next;
}
target.recycle();
target = next;
continue;
}
}
predecessor = target;
target = next;
}
}
// Update list of touch targets for pointer up or cancel, if needed.
if (canceled
|| actionMasked == MotionEvent.ACTION_UP
|| actionMasked == MotionEvent.ACTION_HOVER_MOVE) {
resetTouchState();
} else if (split && actionMasked == MotionEvent.ACTION_POINTER_UP) {
final int actionIndex = ev.getActionIndex();
final int idBitsToRemove = 1 << ev.getPointerId(actionIndex);
removePointersFromTouchTargets(idBitsToRemove);
}
}
if (!handled && mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onUnhandledEvent(ev, 1);
}
return handled;
}
/**
* Resets all touch state in preparation for a new cycle.
*/
private void resetTouchState() {
clearTouchTargets();
resetCancelNextUpFlag(this);
mGroupFlags &= ~FLAG_DISALLOW_INTERCEPT;
}
/**
* Resets the cancel next up flag.
* Returns true if the flag was previously set.
*/
private static boolean resetCancelNextUpFlag(View view) {
if ((view.mPrivateFlags & PFLAG_CANCEL_NEXT_UP_EVENT) != 0) {
view.mPrivateFlags &= ~PFLAG_CANCEL_NEXT_UP_EVENT;
return true;
}
return false;
}
/**
* Clears all touch targets.
*/
private void clearTouchTargets() {
TouchTarget target = mFirstTouchTarget;
if (target != null) {
do {
TouchTarget next = target.next;
target.recycle();
target = next;
} while (target != null);
mFirstTouchTarget = null;
}
}
/**
* Cancels and clears all touch targets.
*/
private void cancelAndClearTouchTargets(MotionEvent event) {
if (mFirstTouchTarget != null) {
boolean syntheticEvent = false;
if (event == null) {
final long now = SystemClock.uptimeMillis();
event = MotionEvent.obtain(now, now,
MotionEvent.ACTION_CANCEL, 0.0f, 0.0f, 0);
event.setSource(InputDevice.SOURCE_TOUCHSCREEN);
syntheticEvent = true;
}
for (TouchTarget target = mFirstTouchTarget; target != null; target = target.next) {
resetCancelNextUpFlag(target.child);
dispatchTransformedTouchEvent(event, true, target.child, target.pointerIdBits);
}
clearTouchTargets();
if (syntheticEvent) {
event.recycle();
}
}
}
/**
* Gets the touch target for specified child view.
* Returns null if not found.
*/
private TouchTarget getTouchTarget(View child) {
for (TouchTarget target = mFirstTouchTarget; target != null; target = target.next) {
if (target.child == child) {
return target;
}
}
return null;
}
/**
* Adds a touch target for specified child to the beginning of the list.
* Assumes the target child is not already present.
*/
private TouchTarget addTouchTarget(View child, int pointerIdBits) {
TouchTarget target = TouchTarget.obtain(child, pointerIdBits);
target.next = mFirstTouchTarget;
mFirstTouchTarget = target;
return target;
}
/**
* Removes the pointer ids from consideration.
*/
private void removePointersFromTouchTargets(int pointerIdBits) {
TouchTarget predecessor = null;
TouchTarget target = mFirstTouchTarget;
while (target != null) {
final TouchTarget next = target.next;
if ((target.pointerIdBits & pointerIdBits) != 0) {
target.pointerIdBits &= ~pointerIdBits;
if (target.pointerIdBits == 0) {
if (predecessor == null) {
mFirstTouchTarget = next;
} else {
predecessor.next = next;
}
target.recycle();
target = next;
continue;
}
}
predecessor = target;
target = next;
}
}
private void cancelTouchTarget(View view) {
TouchTarget predecessor = null;
TouchTarget target = mFirstTouchTarget;
while (target != null) {
final TouchTarget next = target.next;
if (target.child == view) {
if (predecessor == null) {
mFirstTouchTarget = next;
} else {
predecessor.next = next;
}
target.recycle();
final long now = SystemClock.uptimeMillis();
MotionEvent event = MotionEvent.obtain(now, now,
MotionEvent.ACTION_CANCEL, 0.0f, 0.0f, 0);
event.setSource(InputDevice.SOURCE_TOUCHSCREEN);
view.dispatchTouchEvent(event);
event.recycle();
return;
}
predecessor = target;
target = next;
}
}
/**
* Returns true if a child view can receive pointer events.
* @hide
*/
private static boolean canViewReceivePointerEvents(View child) {
return (child.mViewFlags & VISIBILITY_MASK) == VISIBLE
|| child.getAnimation() != null;
}
/**
* Returns true if a child view contains the specified point when transformed
* into its coordinate space.
* Child must not be null.
* @hide
*/
protected boolean isTransformedTouchPointInView(float x, float y, View child,
PointF outLocalPoint) {
float localX = x + mScrollX - child.mLeft;
float localY = y + mScrollY - child.mTop;
if (! child.hasIdentityMatrix() && mAttachInfo != null) {
final float[] localXY = mAttachInfo.mTmpTransformLocation;
localXY[0] = localX;
localXY[1] = localY;
child.getInverseMatrix().mapPoints(localXY);
localX = localXY[0];
localY = localXY[1];
}
final boolean isInView = child.pointInView(localX, localY);
if (isInView && outLocalPoint != null) {
outLocalPoint.set(localX, localY);
}
return isInView;
}
/**
* Transforms a motion event into the coordinate space of a particular child view,
* filters out irrelevant pointer ids, and overrides its action if necessary.
* If child is null, assumes the MotionEvent will be sent to this ViewGroup instead.
*/
private boolean dispatchTransformedTouchEvent(MotionEvent event, boolean cancel,
View child, int desiredPointerIdBits) {
final boolean handled;
// Canceling motions is a special case. We don't need to perform any transformations
// or filtering. The important part is the action, not the contents.
final int oldAction = event.getAction();
if (cancel || oldAction == MotionEvent.ACTION_CANCEL) {
event.setAction(MotionEvent.ACTION_CANCEL);
if (child == null) {
handled = super.dispatchTouchEvent(event);
} else {
handled = child.dispatchTouchEvent(event);
}
event.setAction(oldAction);
return handled;
}
// Calculate the number of pointers to deliver.
final int oldPointerIdBits = event.getPointerIdBits();
final int newPointerIdBits = oldPointerIdBits & desiredPointerIdBits;
// If for some reason we ended up in an inconsistent state where it looks like we
// might produce a motion event with no pointers in it, then drop the event.
if (newPointerIdBits == 0) {
return false;
}
// If the number of pointers is the same and we don't need to perform any fancy
// irreversible transformations, then we can reuse the motion event for this
// dispatch as long as we are careful to revert any changes we make.
// Otherwise we need to make a copy.
final MotionEvent transformedEvent;
if (newPointerIdBits == oldPointerIdBits) {
if (child == null || child.hasIdentityMatrix()) {
if (child == null) {
handled = super.dispatchTouchEvent(event);
} else {
final float offsetX = mScrollX - child.mLeft;
final float offsetY = mScrollY - child.mTop;
event.offsetLocation(offsetX, offsetY);
handled = child.dispatchTouchEvent(event);
event.offsetLocation(-offsetX, -offsetY);
}
return handled;
}
transformedEvent = MotionEvent.obtain(event);
} else {
transformedEvent = event.split(newPointerIdBits);
}
// Perform any necessary transformations and dispatch.
if (child == null) {
handled = super.dispatchTouchEvent(transformedEvent);
} else {
final float offsetX = mScrollX - child.mLeft;
final float offsetY = mScrollY - child.mTop;
transformedEvent.offsetLocation(offsetX, offsetY);
if (! child.hasIdentityMatrix()) {
transformedEvent.transform(child.getInverseMatrix());
}
handled = child.dispatchTouchEvent(transformedEvent);
}
// Done.
transformedEvent.recycle();
return handled;
}
/**
* Enable or disable the splitting of MotionEvents to multiple children during touch event
* dispatch. This behavior is enabled by default for applications that target an
* SDK version of {@link Build.VERSION_CODES#HONEYCOMB} or newer.
*
*
When this option is enabled MotionEvents may be split and dispatched to different child
* views depending on where each pointer initially went down. This allows for user interactions
* such as scrolling two panes of content independently, chording of buttons, and performing
* independent gestures on different pieces of content.
*
* @param split true to allow MotionEvents to be split and dispatched to multiple
* child views. false to only allow one child view to be the target of
* any MotionEvent received by this ViewGroup.
* @attr ref android.R.styleable#ViewGroup_splitMotionEvents
*/
public void setMotionEventSplittingEnabled(boolean split) {
// TODO Applications really shouldn't change this setting mid-touch event,
// but perhaps this should handle that case and send ACTION_CANCELs to any child views
// with gestures in progress when this is changed.
if (split) {
mGroupFlags |= FLAG_SPLIT_MOTION_EVENTS;
} else {
mGroupFlags &= ~FLAG_SPLIT_MOTION_EVENTS;
}
}
/**
* Returns true if MotionEvents dispatched to this ViewGroup can be split to multiple children.
* @return true if MotionEvents dispatched to this ViewGroup can be split to multiple children.
*/
public boolean isMotionEventSplittingEnabled() {
return (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) == FLAG_SPLIT_MOTION_EVENTS;
}
/**
* {@inheritDoc}
*/
public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
if (disallowIntercept == ((mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0)) {
// We're already in this state, assume our ancestors are too
return;
}
if (disallowIntercept) {
mGroupFlags |= FLAG_DISALLOW_INTERCEPT;
} else {
mGroupFlags &= ~FLAG_DISALLOW_INTERCEPT;
}
// Pass it up to our parent
if (mParent != null) {
mParent.requestDisallowInterceptTouchEvent(disallowIntercept);
}
}
/**
* Implement this method to intercept all touch screen motion events. This
* allows you to watch events as they are dispatched to your children, and
* take ownership of the current gesture at any point.
*
*
Using this function takes some care, as it has a fairly complicated
* interaction with {@link View#onTouchEvent(MotionEvent)
* View.onTouchEvent(MotionEvent)}, and using it requires implementing
* that method as well as this one in the correct way. Events will be
* received in the following order:
*
*
*
You will receive the down event here.
*
The down event will be handled either by a child of this view
* group, or given to your own onTouchEvent() method to handle; this means
* you should implement onTouchEvent() to return true, so you will
* continue to see the rest of the gesture (instead of looking for
* a parent view to handle it). Also, by returning true from
* onTouchEvent(), you will not receive any following
* events in onInterceptTouchEvent() and all touch processing must
* happen in onTouchEvent() like normal.
*
For as long as you return false from this function, each following
* event (up to and including the final up) will be delivered first here
* and then to the target's onTouchEvent().
*
If you return true from here, you will not receive any
* following events: the target view will receive the same event but
* with the action {@link MotionEvent#ACTION_CANCEL}, and all further
* events will be delivered to your onTouchEvent() method and no longer
* appear here.
*
*
* @param ev The motion event being dispatched down the hierarchy.
* @return Return true to steal motion events from the children and have
* them dispatched to this ViewGroup through onTouchEvent().
* The current target will receive an ACTION_CANCEL event, and no further
* messages will be delivered here.
*/
public boolean onInterceptTouchEvent(MotionEvent ev) {
return false;
}
/**
* {@inheritDoc}
*
* Looks for a view to give focus to respecting the setting specified by
* {@link #getDescendantFocusability()}.
*
* Uses {@link #onRequestFocusInDescendants(int, android.graphics.Rect)} to
* find focus within the children of this group when appropriate.
*
* @see #FOCUS_BEFORE_DESCENDANTS
* @see #FOCUS_AFTER_DESCENDANTS
* @see #FOCUS_BLOCK_DESCENDANTS
* @see #onRequestFocusInDescendants(int, android.graphics.Rect)
*/
@Override
public boolean requestFocus(int direction, Rect previouslyFocusedRect) {
if (DBG) {
System.out.println(this + " ViewGroup.requestFocus direction="
+ direction);
}
int descendantFocusability = getDescendantFocusability();
switch (descendantFocusability) {
case FOCUS_BLOCK_DESCENDANTS:
return super.requestFocus(direction, previouslyFocusedRect);
case FOCUS_BEFORE_DESCENDANTS: {
final boolean took = super.requestFocus(direction, previouslyFocusedRect);
return took ? took : onRequestFocusInDescendants(direction, previouslyFocusedRect);
}
case FOCUS_AFTER_DESCENDANTS: {
final boolean took = onRequestFocusInDescendants(direction, previouslyFocusedRect);
return took ? took : super.requestFocus(direction, previouslyFocusedRect);
}
default:
throw new IllegalStateException("descendant focusability must be "
+ "one of FOCUS_BEFORE_DESCENDANTS, FOCUS_AFTER_DESCENDANTS, FOCUS_BLOCK_DESCENDANTS "
+ "but is " + descendantFocusability);
}
}
/**
* Look for a descendant to call {@link View#requestFocus} on.
* Called by {@link ViewGroup#requestFocus(int, android.graphics.Rect)}
* when it wants to request focus within its children. Override this to
* customize how your {@link ViewGroup} requests focus within its children.
* @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
* @param previouslyFocusedRect The rectangle (in this View's coordinate system)
* to give a finer grained hint about where focus is coming from. May be null
* if there is no hint.
* @return Whether focus was taken.
*/
@SuppressWarnings({"ConstantConditions"})
protected boolean onRequestFocusInDescendants(int direction,
Rect previouslyFocusedRect) {
int index;
int increment;
int end;
int count = mChildrenCount;
if ((direction & FOCUS_FORWARD) != 0) {
index = 0;
increment = 1;
end = count;
} else {
index = count - 1;
increment = -1;
end = -1;
}
final View[] children = mChildren;
for (int i = index; i != end; i += increment) {
View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
if (child.requestFocus(direction, previouslyFocusedRect)) {
return true;
}
}
}
return false;
}
/**
* {@inheritDoc}
*
* @hide
*/
@Override
public void dispatchStartTemporaryDetach() {
super.dispatchStartTemporaryDetach();
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchStartTemporaryDetach();
}
}
/**
* {@inheritDoc}
*
* @hide
*/
@Override
public void dispatchFinishTemporaryDetach() {
super.dispatchFinishTemporaryDetach();
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchFinishTemporaryDetach();
}
}
/**
* {@inheritDoc}
*/
@Override
void dispatchAttachedToWindow(AttachInfo info, int visibility) {
mGroupFlags |= FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW;
super.dispatchAttachedToWindow(info, visibility);
mGroupFlags &= ~FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW;
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
child.dispatchAttachedToWindow(info,
visibility | (child.mViewFlags & VISIBILITY_MASK));
}
}
@Override
void dispatchScreenStateChanged(int screenState) {
super.dispatchScreenStateChanged(screenState);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchScreenStateChanged(screenState);
}
}
@Override
boolean dispatchPopulateAccessibilityEventInternal(AccessibilityEvent event) {
boolean handled = false;
if (includeForAccessibility()) {
handled = super.dispatchPopulateAccessibilityEventInternal(event);
if (handled) {
return handled;
}
}
// Let our children have a shot in populating the event.
ChildListForAccessibility children = ChildListForAccessibility.obtain(this, true);
try {
final int childCount = children.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = children.getChildAt(i);
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
handled = child.dispatchPopulateAccessibilityEvent(event);
if (handled) {
return handled;
}
}
}
} finally {
children.recycle();
}
return false;
}
@Override
void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) {
super.onInitializeAccessibilityNodeInfoInternal(info);
if (mAttachInfo != null) {
ArrayList childrenForAccessibility = mAttachInfo.mTempArrayList;
childrenForAccessibility.clear();
addChildrenForAccessibility(childrenForAccessibility);
final int childrenForAccessibilityCount = childrenForAccessibility.size();
for (int i = 0; i < childrenForAccessibilityCount; i++) {
View child = childrenForAccessibility.get(i);
info.addChild(child);
}
childrenForAccessibility.clear();
}
}
@Override
void onInitializeAccessibilityEventInternal(AccessibilityEvent event) {
super.onInitializeAccessibilityEventInternal(event);
event.setClassName(ViewGroup.class.getName());
}
@Override
public void notifySubtreeAccessibilityStateChanged(View child, View source, int changeType) {
// If this is a live region, we should send a subtree change event
// from this view. Otherwise, we can let it propagate up.
if (getAccessibilityLiveRegion() != ACCESSIBILITY_LIVE_REGION_NONE) {
notifyViewAccessibilityStateChangedIfNeeded(changeType);
} else if (mParent != null) {
try {
mParent.notifySubtreeAccessibilityStateChanged(this, source, changeType);
} catch (AbstractMethodError e) {
Log.e(VIEW_LOG_TAG, mParent.getClass().getSimpleName() +
" does not fully implement ViewParent", e);
}
}
}
@Override
void resetSubtreeAccessibilityStateChanged() {
super.resetSubtreeAccessibilityStateChanged();
View[] children = mChildren;
final int childCount = mChildrenCount;
for (int i = 0; i < childCount; i++) {
children[i].resetSubtreeAccessibilityStateChanged();
}
}
/**
* {@inheritDoc}
*/
@Override
void dispatchDetachedFromWindow() {
// If we still have a touch target, we are still in the process of
// dispatching motion events to a child; we need to get rid of that
// child to avoid dispatching events to it after the window is torn
// down. To make sure we keep the child in a consistent state, we
// first send it an ACTION_CANCEL motion event.
cancelAndClearTouchTargets(null);
// Similarly, set ACTION_EXIT to all hover targets and clear them.
exitHoverTargets();
// In case view is detached while transition is running
mLayoutCalledWhileSuppressed = false;
// Tear down our drag tracking
mDragNotifiedChildren = null;
if (mCurrentDrag != null) {
mCurrentDrag.recycle();
mCurrentDrag = null;
}
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
children[i].dispatchDetachedFromWindow();
}
super.dispatchDetachedFromWindow();
}
/**
* @hide
*/
@Override
protected void internalSetPadding(int left, int top, int right, int bottom) {
super.internalSetPadding(left, top, right, bottom);
if ((mPaddingLeft | mPaddingTop | mPaddingRight | mPaddingBottom) != 0) {
mGroupFlags |= FLAG_PADDING_NOT_NULL;
} else {
mGroupFlags &= ~FLAG_PADDING_NOT_NULL;
}
}
/**
* {@inheritDoc}
*/
@Override
protected void dispatchSaveInstanceState(SparseArray container) {
super.dispatchSaveInstanceState(container);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
View c = children[i];
if ((c.mViewFlags & PARENT_SAVE_DISABLED_MASK) != PARENT_SAVE_DISABLED) {
c.dispatchSaveInstanceState(container);
}
}
}
/**
* Perform dispatching of a {@link #saveHierarchyState(android.util.SparseArray)} freeze()}
* to only this view, not to its children. For use when overriding
* {@link #dispatchSaveInstanceState(android.util.SparseArray)} dispatchFreeze()} to allow
* subclasses to freeze their own state but not the state of their children.
*
* @param container the container
*/
protected void dispatchFreezeSelfOnly(SparseArray container) {
super.dispatchSaveInstanceState(container);
}
/**
* {@inheritDoc}
*/
@Override
protected void dispatchRestoreInstanceState(SparseArray container) {
super.dispatchRestoreInstanceState(container);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
View c = children[i];
if ((c.mViewFlags & PARENT_SAVE_DISABLED_MASK) != PARENT_SAVE_DISABLED) {
c.dispatchRestoreInstanceState(container);
}
}
}
/**
* Perform dispatching of a {@link #restoreHierarchyState(android.util.SparseArray)}
* to only this view, not to its children. For use when overriding
* {@link #dispatchRestoreInstanceState(android.util.SparseArray)} to allow
* subclasses to thaw their own state but not the state of their children.
*
* @param container the container
*/
protected void dispatchThawSelfOnly(SparseArray container) {
super.dispatchRestoreInstanceState(container);
}
/**
* Enables or disables the drawing cache for each child of this view group.
*
* @param enabled true to enable the cache, false to dispose of it
*/
protected void setChildrenDrawingCacheEnabled(boolean enabled) {
if (enabled || (mPersistentDrawingCache & PERSISTENT_ALL_CACHES) != PERSISTENT_ALL_CACHES) {
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].setDrawingCacheEnabled(enabled);
}
}
}
@Override
protected void onAnimationStart() {
super.onAnimationStart();
// When this ViewGroup's animation starts, build the cache for the children
if ((mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE) {
final int count = mChildrenCount;
final View[] children = mChildren;
final boolean buildCache = !isHardwareAccelerated();
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
child.setDrawingCacheEnabled(true);
if (buildCache) {
child.buildDrawingCache(true);
}
}
}
mGroupFlags |= FLAG_CHILDREN_DRAWN_WITH_CACHE;
}
}
@Override
protected void onAnimationEnd() {
super.onAnimationEnd();
// When this ViewGroup's animation ends, destroy the cache of the children
if ((mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE) {
mGroupFlags &= ~FLAG_CHILDREN_DRAWN_WITH_CACHE;
if ((mPersistentDrawingCache & PERSISTENT_ANIMATION_CACHE) == 0) {
setChildrenDrawingCacheEnabled(false);
}
}
}
@Override
Bitmap createSnapshot(Bitmap.Config quality, int backgroundColor, boolean skipChildren) {
int count = mChildrenCount;
int[] visibilities = null;
if (skipChildren) {
visibilities = new int[count];
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
visibilities[i] = child.getVisibility();
if (visibilities[i] == View.VISIBLE) {
child.setVisibility(INVISIBLE);
}
}
}
Bitmap b = super.createSnapshot(quality, backgroundColor, skipChildren);
if (skipChildren) {
for (int i = 0; i < count; i++) {
getChildAt(i).setVisibility(visibilities[i]);
}
}
return b;
}
/** Return true if this ViewGroup is laying out using optical bounds. */
boolean isLayoutModeOptical() {
return mLayoutMode == LAYOUT_MODE_OPTICAL_BOUNDS;
}
Insets computeOpticalInsets() {
if (isLayoutModeOptical()) {
int left = 0;
int top = 0;
int right = 0;
int bottom = 0;
for (int i = 0; i < mChildrenCount; i++) {
View child = getChildAt(i);
if (child.getVisibility() == VISIBLE) {
Insets insets = child.getOpticalInsets();
left = Math.max(left, insets.left);
top = Math.max(top, insets.top);
right = Math.max(right, insets.right);
bottom = Math.max(bottom, insets.bottom);
}
}
return Insets.of(left, top, right, bottom);
} else {
return Insets.NONE;
}
}
private static void fillRect(Canvas canvas, Paint paint, int x1, int y1, int x2, int y2) {
if (x1 != x2 && y1 != y2) {
if (x1 > x2) {
int tmp = x1; x1 = x2; x2 = tmp;
}
if (y1 > y2) {
int tmp = y1; y1 = y2; y2 = tmp;
}
canvas.drawRect(x1, y1, x2, y2, paint);
}
}
private static int sign(int x) {
return (x >= 0) ? 1 : -1;
}
private static void drawCorner(Canvas c, Paint paint, int x1, int y1, int dx, int dy, int lw) {
fillRect(c, paint, x1, y1, x1 + dx, y1 + lw * sign(dy));
fillRect(c, paint, x1, y1, x1 + lw * sign(dx), y1 + dy);
}
private int dipsToPixels(int dips) {
float scale = getContext().getResources().getDisplayMetrics().density;
return (int) (dips * scale + 0.5f);
}
private static void drawRectCorners(Canvas canvas, int x1, int y1, int x2, int y2, Paint paint,
int lineLength, int lineWidth) {
drawCorner(canvas, paint, x1, y1, lineLength, lineLength, lineWidth);
drawCorner(canvas, paint, x1, y2, lineLength, -lineLength, lineWidth);
drawCorner(canvas, paint, x2, y1, -lineLength, lineLength, lineWidth);
drawCorner(canvas, paint, x2, y2, -lineLength, -lineLength, lineWidth);
}
private static void fillDifference(Canvas canvas,
int x2, int y2, int x3, int y3,
int dx1, int dy1, int dx2, int dy2, Paint paint) {
int x1 = x2 - dx1;
int y1 = y2 - dy1;
int x4 = x3 + dx2;
int y4 = y3 + dy2;
fillRect(canvas, paint, x1, y1, x4, y2);
fillRect(canvas, paint, x1, y2, x2, y3);
fillRect(canvas, paint, x3, y2, x4, y3);
fillRect(canvas, paint, x1, y3, x4, y4);
}
/**
* @hide
*/
protected void onDebugDrawMargins(Canvas canvas, Paint paint) {
for (int i = 0; i < getChildCount(); i++) {
View c = getChildAt(i);
c.getLayoutParams().onDebugDraw(c, canvas, paint);
}
}
/**
* @hide
*/
protected void onDebugDraw(Canvas canvas) {
Paint paint = getDebugPaint();
// Draw optical bounds
{
paint.setColor(Color.RED);
paint.setStyle(Paint.Style.STROKE);
for (int i = 0; i < getChildCount(); i++) {
View c = getChildAt(i);
Insets insets = c.getOpticalInsets();
drawRect(canvas, paint,
c.getLeft() + insets.left,
c.getTop() + insets.top,
c.getRight() - insets.right - 1,
c.getBottom() - insets.bottom - 1);
}
}
// Draw margins
{
paint.setColor(Color.argb(63, 255, 0, 255));
paint.setStyle(Paint.Style.FILL);
onDebugDrawMargins(canvas, paint);
}
// Draw clip bounds
{
paint.setColor(Color.rgb(63, 127, 255));
paint.setStyle(Paint.Style.FILL);
int lineLength = dipsToPixels(8);
int lineWidth = dipsToPixels(1);
for (int i = 0; i < getChildCount(); i++) {
View c = getChildAt(i);
drawRectCorners(canvas, c.getLeft(), c.getTop(), c.getRight(), c.getBottom(),
paint, lineLength, lineWidth);
}
}
}
/**
* {@inheritDoc}
*/
@Override
//ViewGroup 的绘制实际上调用的dispatchDraw，绘制时需要考虑动画问题，而动画实际上就是通过dispatchDraw来实现的
//绘制子组件调用的是drawChild方法，
protected void dispatchDraw(Canvas canvas) {
final int count = mChildrenCount;
final View[] children = mChildren;
int flags = mGroupFlags;
if ((flags & FLAG_RUN_ANIMATION) != 0 && canAnimate()) {
final boolean cache = (mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE;
final boolean buildCache = !isHardwareAccelerated();
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
final LayoutParams params = child.getLayoutParams();
attachLayoutAnimationParameters(child, params, i, count);
bindLayoutAnimation(child);
if (cache) {
child.setDrawingCacheEnabled(true);
if (buildCache) {
child.buildDrawingCache(true);
}
}
}
}
final LayoutAnimationController controller = mLayoutAnimationController;
if (controller.willOverlap()) {
mGroupFlags |= FLAG_OPTIMIZE_INVALIDATE;
}
controller.start();
mGroupFlags &= ~FLAG_RUN_ANIMATION;
mGroupFlags &= ~FLAG_ANIMATION_DONE;
if (cache) {
mGroupFlags |= FLAG_CHILDREN_DRAWN_WITH_CACHE;
}
if (mAnimationListener != null) {
mAnimationListener.onAnimationStart(controller.getAnimation());
}
}
int saveCount = 0;
final boolean clipToPadding = (flags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK;
if (clipToPadding) {
saveCount = canvas.save();
canvas.clipRect(mScrollX + mPaddingLeft, mScrollY + mPaddingTop,
mScrollX + mRight - mLeft - mPaddingRight,
mScrollY + mBottom - mTop - mPaddingBottom);
}
// We will draw our child's animation, let's reset the flag
mPrivateFlags &= ~PFLAG_DRAW_ANIMATION;
mGroupFlags &= ~FLAG_INVALIDATE_REQUIRED;
boolean more = false;
final long drawingTime = getDrawingTime();
if ((flags & FLAG_USE_CHILD_DRAWING_ORDER) == 0) {
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE || child.getAnimation() != null) {
more |= drawChild(canvas, child, drawingTime);
}
}
} else {
for (int i = 0; i < count; i++) {
final View child = children[getChildDrawingOrder(count, i)];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE || child.getAnimation() != null) {
more |= drawChild(canvas, child, drawingTime);
}
}
}
// Draw any disappearing views that have animations
if (mDisappearingChildren != null) {
final ArrayList disappearingChildren = mDisappearingChildren;
final int disappearingCount = disappearingChildren.size() - 1;
// Go backwards -- we may delete as animations finish
for (int i = disappearingCount; i >= 0; i--) {
final View child = disappearingChildren.get(i);
more |= drawChild(canvas, child, drawingTime);
}
}
if (debugDraw()) {
onDebugDraw(canvas);
}
if (clipToPadding) {
canvas.restoreToCount(saveCount);
}
// mGroupFlags might have been updated by drawChild()
flags = mGroupFlags;
if ((flags & FLAG_INVALIDATE_REQUIRED) == FLAG_INVALIDATE_REQUIRED) {
invalidate(true);
}
if ((flags & FLAG_ANIMATION_DONE) == 0 && (flags & FLAG_NOTIFY_ANIMATION_LISTENER) == 0 &&
mLayoutAnimationController.isDone() && !more) {
// We want to erase the drawing cache and notify the listener after the
// next frame is drawn because one extra invalidate() is caused by
// drawChild() after the animation is over
mGroupFlags |= FLAG_NOTIFY_ANIMATION_LISTENER;
final Runnable end = new Runnable() {
public void run() {
notifyAnimationListener();
}
};
post(end);
}
}
/**
* Returns the ViewGroupOverlay for this view group, creating it if it does
* not yet exist. In addition to {@link ViewOverlay}'s support for drawables,
* {@link ViewGroupOverlay} allows views to be added to the overlay. These
* views, like overlay drawables, are visual-only; they do not receive input
* events and should not be used as anything other than a temporary
* representation of a view in a parent container, such as might be used
* by an animation effect.
*
*
Note: Overlays do not currently work correctly with {@link
* SurfaceView} or {@link TextureView}; contents in overlays for these
* types of views may not display correctly.
*
* @return The ViewGroupOverlay object for this view.
* @see ViewGroupOverlay
*/
@Override
public ViewGroupOverlay getOverlay() {
if (mOverlay == null) {
mOverlay = new ViewGroupOverlay(mContext, this);
}
return (ViewGroupOverlay) mOverlay;
}
/**
* Returns the index of the child to draw for this iteration. Override this
* if you want to change the drawing order of children. By default, it
* returns i.
*
* NOTE: In order for this method to be called, you must enable child ordering
* first by calling {@link #setChildrenDrawingOrderEnabled(boolean)}.
*
* @param i The current iteration.
* @return The index of the child to draw this iteration.
*
* @see #setChildrenDrawingOrderEnabled(boolean)
* @see #isChildrenDrawingOrderEnabled()
*/
protected int getChildDrawingOrder(int childCount, int i) {
return i;
}
private void notifyAnimationListener() {
mGroupFlags &= ~FLAG_NOTIFY_ANIMATION_LISTENER;
mGroupFlags |= FLAG_ANIMATION_DONE;
if (mAnimationListener != null) {
final Runnable end = new Runnable() {
public void run() {
mAnimationListener.onAnimationEnd(mLayoutAnimationController.getAnimation());
}
};
post(end);
}
if ((mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE) {
mGroupFlags &= ~FLAG_CHILDREN_DRAWN_WITH_CACHE;
if ((mPersistentDrawingCache & PERSISTENT_ANIMATION_CACHE) == 0) {
setChildrenDrawingCacheEnabled(false);
}
}
invalidate(true);
}
/**
* This method is used to cause children of this ViewGroup to restore or recreate their
* display lists. It is called by getDisplayList() when the parent ViewGroup does not need
* to recreate its own display list, which would happen if it went through the normal
* draw/dispatchDraw mechanisms.
*
* @hide
*/
@Override
protected void dispatchGetDisplayList() {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View child = children[i];
if (((child.mViewFlags & VISIBILITY_MASK) == VISIBLE || child.getAnimation() != null) &&
child.hasStaticLayer()) {
child.mRecreateDisplayList = (child.mPrivateFlags & PFLAG_INVALIDATED)
== PFLAG_INVALIDATED;
child.mPrivateFlags &= ~PFLAG_INVALIDATED;
child.getDisplayList();
child.mRecreateDisplayList = false;
}
}
if (mOverlay != null) {
View overlayView = mOverlay.getOverlayView();
overlayView.mRecreateDisplayList = (overlayView.mPrivateFlags & PFLAG_INVALIDATED)
== PFLAG_INVALIDATED;
overlayView.mPrivateFlags &= ~PFLAG_INVALIDATED;
overlayView.getDisplayList();
overlayView.mRecreateDisplayList = false;
}
}
/**
* Draw one child of this View Group. This method is responsible for getting
* the canvas in the right state. This includes clipping, translating so
* that the child's scrolled origin is at 0, 0, and applying any animation
* transformations.
*
* @param canvas The canvas on which to draw the child
* @param child Who to draw
* @param drawingTime The time at which draw is occurring
* @return True if an invalidate() was issued
*/
protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
return child.draw(canvas, this, drawingTime);
}
/**
* Returns whether ths group's children are clipped to their bounds before drawing.
* The default value is true.
* @see #setClipChildren(boolean)
*
* @return True if the group's children will be clipped to their bounds,
* false otherwise.
*/
public boolean getClipChildren() {
return ((mGroupFlags & FLAG_CLIP_CHILDREN) != 0);
}
/**
* By default, children are clipped to their bounds before drawing. This
* allows view groups to override this behavior for animations, etc.
*
* @param clipChildren true to clip children to their bounds,
* false otherwise
* @attr ref android.R.styleable#ViewGroup_clipChildren
*/
public void setClipChildren(boolean clipChildren) {
boolean previousValue = (mGroupFlags & FLAG_CLIP_CHILDREN) == FLAG_CLIP_CHILDREN;
if (clipChildren != previousValue) {
setBooleanFlag(FLAG_CLIP_CHILDREN, clipChildren);
for (int i = 0; i < mChildrenCount; ++i) {
View child = getChildAt(i);
if (child.mDisplayList != null) {
child.mDisplayList.setClipToBounds(clipChildren);
}
}
}
}
/**
* By default, children are clipped to the padding of the ViewGroup. This
* allows view groups to override this behavior
*
* @param clipToPadding true to clip children to the padding of the
* group, false otherwise
* @attr ref android.R.styleable#ViewGroup_clipToPadding
*/
public void setClipToPadding(boolean clipToPadding) {
setBooleanFlag(FLAG_CLIP_TO_PADDING, clipToPadding);
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchSetSelected(boolean selected) {
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].setSelected(selected);
}
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchSetActivated(boolean activated) {
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].setActivated(activated);
}
}
@Override
protected void dispatchSetPressed(boolean pressed) {
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
final View child = children[i];
// Children that are clickable on their own should not
// show a pressed state when their parent view does.
// Clearing a pressed state always propagates.
if (!pressed || (!child.isClickable() && !child.isLongClickable())) {
child.setPressed(pressed);
}
}
}
@Override
void dispatchCancelPendingInputEvents() {
super.dispatchCancelPendingInputEvents();
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].dispatchCancelPendingInputEvents();
}
}
/**
* When this property is set to true, this ViewGroup supports static transformations on
* children; this causes
* {@link #getChildStaticTransformation(View, android.view.animation.Transformation)} to be
* invoked when a child is drawn.
*
* Any subclass overriding
* {@link #getChildStaticTransformation(View, android.view.animation.Transformation)} should
* set this property to true.
*
* @param enabled True to enable static transformations on children, false otherwise.
*
* @see #getChildStaticTransformation(View, android.view.animation.Transformation)
*/
protected void setStaticTransformationsEnabled(boolean enabled) {
setBooleanFlag(FLAG_SUPPORT_STATIC_TRANSFORMATIONS, enabled);
}
/**
* Sets t to be the static transformation of the child, if set, returning a
* boolean to indicate whether a static transform was set. The default implementation
* simply returns false; subclasses may override this method for different
* behavior. {@link #setStaticTransformationsEnabled(boolean)} must be set to true
* for this method to be called.
*
* @param child The child view whose static transform is being requested
* @param t The Transformation which will hold the result
* @return true if the transformation was set, false otherwise
* @see #setStaticTransformationsEnabled(boolean)
*/
protected boolean getChildStaticTransformation(View child, Transformation t) {
return false;
}
Transformation getChildTransformation() {
if (mChildTransformation == null) {
mChildTransformation = new Transformation();
}
return mChildTransformation;
}
/**
* {@hide}
*/
@Override
protected View findViewTraversal(int id) {
if (id == mID) {
return this;
}
final View[] where = mChildren;
final int len = mChildrenCount;
for (int i = 0; i < len; i++) {
View v = where[i];
if ((v.mPrivateFlags & PFLAG_IS_ROOT_NAMESPACE) == 0) {
v = v.findViewById(id);
if (v != null) {
return v;
}
}
}
return null;
}
/**
* {@hide}
*/
@Override
protected View findViewWithTagTraversal(Object tag) {
if (tag != null && tag.equals(mTag)) {
return this;
}
final View[] where = mChildren;
final int len = mChildrenCount;
for (int i = 0; i < len; i++) {
View v = where[i];
if ((v.mPrivateFlags & PFLAG_IS_ROOT_NAMESPACE) == 0) {
v = v.findViewWithTag(tag);
if (v != null) {
return v;
}
}
}
return null;
}
/**
* {@hide}
*/
@Override
protected View findViewByPredicateTraversal(Predicate predicate, View childToSkip) {
if (predicate.apply(this)) {
return this;
}
final View[] where = mChildren;
final int len = mChildrenCount;
for (int i = 0; i < len; i++) {
View v = where[i];
if (v != childToSkip && (v.mPrivateFlags & PFLAG_IS_ROOT_NAMESPACE) == 0) {
v = v.findViewByPredicate(predicate);
if (v != null) {
return v;
}
}
}
return null;
}
/**
*
Adds a child view. If no layout parameters are already set on the child, the
* default parameters for this ViewGroup are set on the child.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param child the child view to add
*
* @see #generateDefaultLayoutParams()
*/
public void addView(View child) {
addView(child, -1);
}
/**
* Adds a child view. If no layout parameters are already set on the child, the
* default parameters for this ViewGroup are set on the child.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param child the child view to add
* @param index the position at which to add the child
*
* @see #generateDefaultLayoutParams()
*/
public void addView(View child, int index) {
LayoutParams params = child.getLayoutParams();
if (params == null) {
params = generateDefaultLayoutParams();
if (params == null) {
throw new IllegalArgumentException("generateDefaultLayoutParams() cannot return null");
}
}
addView(child, index, params);
}
/**
* Adds a child view with this ViewGroup's default layout parameters and the
* specified width and height.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param child the child view to add
*/
public void addView(View child, int width, int height) {
final LayoutParams params = generateDefaultLayoutParams();
params.width = width;
params.height = height;
addView(child, -1, params);
}
/**
* Adds a child view with the specified layout parameters.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param child the child view to add
* @param params the layout parameters to set on the child
*/
public void addView(View child, LayoutParams params) {
addView(child, -1, params);
}
/**
* Adds a child view with the specified layout parameters.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param child the child view to add
* @param index the position at which to add the child
* @param params the layout parameters to set on the child
*/
public void addView(View child, int index, LayoutParams params) {
if (DBG) {
System.out.println(this + " addView");
}
// addViewInner() will call child.requestLayout() when setting the new LayoutParams
// therefore, we call requestLayout() on ourselves before, so that the child's request
// will be blocked at our level
requestLayout();
invalidate(true);
addViewInner(child, index, params, false);
}
/**
* {@inheritDoc}
*/
public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
if (!checkLayoutParams(params)) {
throw new IllegalArgumentException("Invalid LayoutParams supplied to " + this);
}
if (view.mParent != this) {
throw new IllegalArgumentException("Given view not a child of " + this);
}
view.setLayoutParams(params);
}
/**
* {@inheritDoc}
*/
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
return p != null;
}
/**
* Interface definition for a callback to be invoked when the hierarchy
* within this view changed. The hierarchy changes whenever a child is added
* to or removed from this view.
*/
public interface OnHierarchyChangeListener {
/**
* Called when a new child is added to a parent view.
*
* @param parent the view in which a child was added
* @param child the new child view added in the hierarchy
*/
void onChildViewAdded(View parent, View child);
/**
* Called when a child is removed from a parent view.
*
* @param parent the view from which the child was removed
* @param child the child removed from the hierarchy
*/
void onChildViewRemoved(View parent, View child);
}
/**
* Register a callback to be invoked when a child is added to or removed
* from this view.
*
* @param listener the callback to invoke on hierarchy change
*/
public void setOnHierarchyChangeListener(OnHierarchyChangeListener listener) {
mOnHierarchyChangeListener = listener;
}
/**
* @hide
*/
protected void onViewAdded(View child) {
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewAdded(this, child);
}
}
/**
* @hide
*/
protected void onViewRemoved(View child) {
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewRemoved(this, child);
}
}
private void clearCachedLayoutMode() {
if (!hasBooleanFlag(FLAG_LAYOUT_MODE_WAS_EXPLICITLY_SET)) {
mLayoutMode = LAYOUT_MODE_UNDEFINED;
}
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
clearCachedLayoutMode();
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
clearCachedLayoutMode();
}
/**
* Adds a view during layout. This is useful if in your onLayout() method,
* you need to add more views (as does the list view for example).
*
* If index is negative, it means put it at the end of the list.
*
* @param child the view to add to the group
* @param index the index at which the child must be added
* @param params the layout parameters to associate with the child
* @return true if the child was added, false otherwise
*/
//添加View的算法
//addViewInLayout addViewInner addInArray 这四个方法都是添加View的核心算法的封装，它们是层层调用的关系，而我们通常调用的addView就是最终通过这几个函数来添加View到ViewGroup中的
protected boolean addViewInLayout(View child, int index, LayoutParams params) {
return addViewInLayout(child, index, params, false);
}
/**
* Adds a view during layout. This is useful if in your onLayout() method,
* you need to add more views (as does the list view for example).
*
* If index is negative, it means put it at the end of the list.
*
* @param child the view to add to the group
* @param index the index at which the child must be added
* @param params the layout parameters to associate with the child
* @param preventRequestLayout if true, calling this method will not trigger a
* layout request on child
* @return true if the child was added, false otherwise
*/
protected boolean addViewInLayout(View child, int index, LayoutParams params,
boolean preventRequestLayout) {
child.mParent = null;
addViewInner(child, index, params, preventRequestLayout);
child.mPrivateFlags = (child.mPrivateFlags & ~PFLAG_DIRTY_MASK) | PFLAG_DRAWN;
return true;
}
/**
* Prevents the specified child to be laid out during the next layout pass.
*
* @param child the child on which to perform the cleanup
*/
protected void cleanupLayoutState(View child) {
child.mPrivateFlags &= ~View.PFLAG_FORCE_LAYOUT;
}
private void addViewInner(View child, int index, LayoutParams params,
boolean preventRequestLayout) {
if (mTransition != null) {
// Don't prevent other add transitions from completing, but cancel remove
// transitions to let them complete the process before we add to the container
mTransition.cancel(LayoutTransition.DISAPPEARING);
}
//首先是对子View是否已经包含到一个父容器中，主要的是防止添加一个已有父容器的VIew，因为添加一个拥有父容器的
//View时会碰到各种问题。比如记录本身父容器算法的问题，本身被多个父容器包含时更新的处理等等一系列的问题
if (child.getParent() != null) {
throw new IllegalStateException("The specified child already has a parent. " +
"You must call removeView() on the child's parent first.");
}
if (mTransition != null) {
mTransition.addChild(this, child);
}
//对子View布局参数的处理
if (!checkLayoutParams(params)) {
params = generateLayoutParams(params);
}
if (preventRequestLayout) {
child.mLayoutParams = params;
} else {
child.setLayoutParams(params);
}
if (index < 0) {
index = mChildrenCount;
}
//调用addInArray来添加View
addInArray(child, index);
// tell our children
//父VIew为当前的ViewGroup
if (preventRequestLayout) {
child.assignParent(this);
} else {
child.mParent = this;
}
//焦点的处理
if (child.hasFocus()) {
requestChildFocus(child, child.findFocus());
}
//当前View的AttachInfo信息，这个信息是用来在窗口处理中用的。
//Android的窗口系统就是通过AttachInfo来判断View的所属窗口的
AttachInfo ai = mAttachInfo;
if (ai != null && (mGroupFlags & FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW) == 0) {
boolean lastKeepOn = ai.mKeepScreenOn;
ai.mKeepScreenOn = false;
child.dispatchAttachedToWindow(mAttachInfo, (mViewFlags&VISIBILITY_MASK));
if (ai.mKeepScreenOn) {
needGlobalAttributesUpdate(true);
}
ai.mKeepScreenOn = lastKeepOn;
}
if (child.isLayoutDirectionInherited()) {
child.resetRtlProperties();
}
//View 树改变的监听
onViewAdded(child);
//子View中的mViewFlags的设置
if ((child.mViewFlags & DUPLICATE_PARENT_STATE) == DUPLICATE_PARENT_STATE) {
mGroupFlags |= FLAG_NOTIFY_CHILDREN_ON_DRAWABLE_STATE_CHANGE;
}
if (child.hasTransientState()) {
childHasTransientStateChanged(child, true);
}
if (child.isImportantForAccessibility() && child.getVisibility() != View.GONE) {
notifySubtreeAccessibilityStateChangedIfNeeded();
}
}
//此类里面主要是通过System.arraycopy来添加View的
private void addInArray(View child, int index) {
View[] children = mChildren;
final int count = mChildrenCount;
final int size = children.length;
if (index == count) {
if (size == count) {
mChildren = new View[size + ARRAY_CAPACITY_INCREMENT];
System.arraycopy(children, 0, mChildren, 0, size);
children = mChildren;
}
children[mChildrenCount++] = child;
} else if (index < count) {
if (size == count) {
mChildren = new View[size + ARRAY_CAPACITY_INCREMENT];
System.arraycopy(children, 0, mChildren, 0, index);
System.arraycopy(children, index, mChildren, index + 1, count - index);
children = mChildren;
} else {
System.arraycopy(children, index, children, index + 1, count - index);
}
children[index] = child;
mChildrenCount++;
if (mLastTouchDownIndex >= index) {
mLastTouchDownIndex++;
}
} else {
throw new IndexOutOfBoundsException("index=" + index + " count=" + count);
}
}
// This method also sets the child's mParent to null
//移除View的方式
private void removeFromArray(int index) {
final View[] children = mChildren;
if (!(mTransitioningViews != null && mTransitioningViews.contains(children[index]))) {
children[index].mParent = null;
}
final int count = mChildrenCount;
if (index == count - 1) {
children[--mChildrenCount] = null;
} else if (index >= 0 && index < count) {
System.arraycopy(children, index + 1, children, index, count - index - 1);
children[--mChildrenCount] = null;
} else {
throw new IndexOutOfBoundsException();
}
if (mLastTouchDownIndex == index) {
mLastTouchDownTime = 0;
mLastTouchDownIndex = -1;
} else if (mLastTouchDownIndex > index) {
mLastTouchDownIndex--;
}
}
// This method also sets the children's mParent to null
private void removeFromArray(int start, int count) {
final View[] children = mChildren;
final int childrenCount = mChildrenCount;
start = Math.max(0, start);
final int end = Math.min(childrenCount, start + count);
if (start == end) {
return;
}
if (end == childrenCount) {
for (int i = start; i < end; i++) {
children[i].mParent = null;
children[i] = null;
}
} else {
for (int i = start; i < end; i++) {
children[i].mParent = null;
}
// Since we're looping above, we might as well do the copy, but is arraycopy()
// faster than the extra 2 bounds checks we would do in the loop?
System.arraycopy(children, end, children, start, childrenCount - end);
for (int i = childrenCount - (end - start); i < childrenCount; i++) {
children[i] = null;
}
}
mChildrenCount -= (end - start);
}
private void bindLayoutAnimation(View child) {
Animation a = mLayoutAnimationController.getAnimationForView(child);
child.setAnimation(a);
}
/**
* Subclasses should override this method to set layout animation
* parameters on the supplied child.
*
* @param child the child to associate with animation parameters
* @param params the child's layout parameters which hold the animation
* parameters
* @param index the index of the child in the view group
* @param count the number of children in the view group
*/
protected void attachLayoutAnimationParameters(View child,
LayoutParams params, int index, int count) {
LayoutAnimationController.AnimationParameters animationParams =
params.layoutAnimationParameters;
if (animationParams == null) {
animationParams = new LayoutAnimationController.AnimationParameters();
params.layoutAnimationParameters = animationParams;
}
animationParams.count = count;
animationParams.index = index;
}
/**
* {@inheritDoc}
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*/
public void removeView(View view) {
removeViewInternal(view);
requestLayout();
invalidate(true);
}
/**
* Removes a view during layout. This is useful if in your onLayout() method,
* you need to remove more views.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param view the view to remove from the group
*/
public void removeViewInLayout(View view) {
removeViewInternal(view);
}
/**
* Removes a range of views during layout. This is useful if in your onLayout() method,
* you need to remove more views.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param start the index of the first view to remove from the group
* @param count the number of views to remove from the group
*/
public void removeViewsInLayout(int start, int count) {
removeViewsInternal(start, count);
}
/**
* Removes the view at the specified position in the group.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param index the position in the group of the view to remove
*/
public void removeViewAt(int index) {
removeViewInternal(index, getChildAt(index));
requestLayout();
invalidate(true);
}
/**
* Removes the specified range of views from the group.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*
* @param start the first position in the group of the range of views to remove
* @param count the number of views to remove
*/
public void removeViews(int start, int count) {
removeViewsInternal(start, count);
requestLayout();
invalidate(true);
}
private void removeViewInternal(View view) {
final int index = indexOfChild(view);
if (index >= 0) {
removeViewInternal(index, view);
}
}
private void removeViewInternal(int index, View view) {
if (mTransition != null) {
mTransition.removeChild(this, view);
}
boolean clearChildFocus = false;
if (view == mFocused) {
view.unFocus();
clearChildFocus = true;
}
if (view.isAccessibilityFocused()) {
view.clearAccessibilityFocus();
}
cancelTouchTarget(view);
cancelHoverTarget(view);
if (view.getAnimation() != null ||
(mTransitioningViews != null && mTransitioningViews.contains(view))) {
addDisappearingView(view);
} else if (view.mAttachInfo != null) {
view.dispatchDetachedFromWindow();
}
if (view.hasTransientState()) {
childHasTransientStateChanged(view, false);
}
needGlobalAttributesUpdate(false);
removeFromArray(index);
if (clearChildFocus) {
clearChildFocus(view);
if (!rootViewRequestFocus()) {
notifyGlobalFocusCleared(this);
}
}
onViewRemoved(view);
if (view.isImportantForAccessibility() && view.getVisibility() != View.GONE) {
notifySubtreeAccessibilityStateChangedIfNeeded();
}
}
/**
* Sets the LayoutTransition object for this ViewGroup. If the LayoutTransition object is
* not null, changes in layout which occur because of children being added to or removed from
* the ViewGroup will be animated according to the animations defined in that LayoutTransition
* object. By default, the transition object is null (so layout changes are not animated).
*
*
Replacing a non-null transition will cause that previous transition to be
* canceled, if it is currently running, to restore this container to
* its correct post-transition state.
*
* @param transition The LayoutTransition object that will animated changes in layout. A value
* of null means no transition will run on layout changes.
* @attr ref android.R.styleable#ViewGroup_animateLayoutChanges
*/
public void setLayoutTransition(LayoutTransition transition) {
if (mTransition != null) {
LayoutTransition previousTransition = mTransition;
previousTransition.cancel();
previousTransition.removeTransitionListener(mLayoutTransitionListener);
}
mTransition = transition;
if (mTransition != null) {
mTransition.addTransitionListener(mLayoutTransitionListener);
}
}
/**
* Gets the LayoutTransition object for this ViewGroup. If the LayoutTransition object is
* not null, changes in layout which occur because of children being added to or removed from
* the ViewGroup will be animated according to the animations defined in that LayoutTransition
* object. By default, the transition object is null (so layout changes are not animated).
*
* @return LayoutTranstion The LayoutTransition object that will animated changes in layout.
* A value of null means no transition will run on layout changes.
*/
public LayoutTransition getLayoutTransition() {
return mTransition;
}
private void removeViewsInternal(int start, int count) {
final View focused = mFocused;
final boolean detach = mAttachInfo != null;
boolean clearChildFocus = false;
final View[] children = mChildren;
final int end = start + count;
for (int i = start; i < end; i++) {
final View view = children[i];
if (mTransition != null) {
mTransition.removeChild(this, view);
}
if (view == focused) {
view.unFocus();
clearChildFocus = true;
}
if (view.isAccessibilityFocused()) {
view.clearAccessibilityFocus();
}
cancelTouchTarget(view);
cancelHoverTarget(view);
if (view.getAnimation() != null ||
(mTransitioningViews != null && mTransitioningViews.contains(view))) {
addDisappearingView(view);
} else if (detach) {
view.dispatchDetachedFromWindow();
}
if (view.hasTransientState()) {
childHasTransientStateChanged(view, false);
}
needGlobalAttributesUpdate(false);
onViewRemoved(view);
}
removeFromArray(start, count);
if (clearChildFocus) {
clearChildFocus(focused);
if (!rootViewRequestFocus()) {
notifyGlobalFocusCleared(focused);
}
}
}
/**
* Call this method to remove all child views from the
* ViewGroup.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*/
public void removeAllViews() {
removeAllViewsInLayout();
requestLayout();
invalidate(true);
}
/**
* Called by a ViewGroup subclass to remove child views from itself,
* when it must first know its size on screen before it can calculate how many
* child views it will render. An example is a Gallery or a ListView, which
* may "have" 50 children, but actually only render the number of children
* that can currently fit inside the object on screen. Do not call
* this method unless you are extending ViewGroup and understand the
* view measuring and layout pipeline.
*
*
Note: do not invoke this method from
* {@link #draw(android.graphics.Canvas)}, {@link #onDraw(android.graphics.Canvas)},
* {@link #dispatchDraw(android.graphics.Canvas)} or any related method.
*/
public void removeAllViewsInLayout() {
final int count = mChildrenCount;
if (count <= 0) {
return;
}
final View[] children = mChildren;
mChildrenCount = 0;
final View focused = mFocused;
final boolean detach = mAttachInfo != null;
boolean clearChildFocus = false;
needGlobalAttributesUpdate(false);
for (int i = count - 1; i >= 0; i--) {
final View view = children[i];
if (mTransition != null) {
mTransition.removeChild(this, view);
}
if (view == focused) {
view.unFocus();
clearChildFocus = true;
}
if (view.isAccessibilityFocused()) {
view.clearAccessibilityFocus();
}
cancelTouchTarget(view);
cancelHoverTarget(view);
if (view.getAnimation() != null ||
(mTransitioningViews != null && mTransitioningViews.contains(view))) {
addDisappearingView(view);
} else if (detach) {
view.dispatchDetachedFromWindow();
}
if (view.hasTransientState()) {
childHasTransientStateChanged(view, false);
}
onViewRemoved(view);
view.mParent = null;
children[i] = null;
}
if (clearChildFocus) {
clearChildFocus(focused);
if (!rootViewRequestFocus()) {
notifyGlobalFocusCleared(focused);
}
}
}
/**
* Finishes the removal of a detached view. This method will dispatch the detached from
* window event and notify the hierarchy change listener.
*
* This method is intended to be lightweight and makes no assumptions about whether the
* parent or child should be redrawn. Proper use of this method will include also making
* any appropriate {@link #requestLayout()} or {@link #invalidate()} calls.
* For example, callers can {@link #post(Runnable) post} a {@link Runnable}
* which performs a {@link #requestLayout()} on the next frame, after all detach/remove
* calls are finished, causing layout to be run prior to redrawing the view hierarchy.
*
* @param child the child to be definitely removed from the view hierarchy
* @param animate if true and the view has an animation, the view is placed in the
* disappearing views list, otherwise, it is detached from the window
*
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #detachAllViewsFromParent()
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
*/
protected void removeDetachedView(View child, boolean animate) {
if (mTransition != null) {
mTransition.removeChild(this, child);
}
if (child == mFocused) {
child.clearFocus();
}
child.clearAccessibilityFocus();
cancelTouchTarget(child);
cancelHoverTarget(child);
if ((animate && child.getAnimation() != null) ||
(mTransitioningViews != null && mTransitioningViews.contains(child))) {
addDisappearingView(child);
} else if (child.mAttachInfo != null) {
child.dispatchDetachedFromWindow();
}
if (child.hasTransientState()) {
childHasTransientStateChanged(child, false);
}
onViewRemoved(child);
}
/**
* Attaches a view to this view group. Attaching a view assigns this group as the parent,
* sets the layout parameters and puts the view in the list of children so that
* it can be retrieved by calling {@link #getChildAt(int)}.
*
* This method is intended to be lightweight and makes no assumptions about whether the
* parent or child should be redrawn. Proper use of this method will include also making
* any appropriate {@link #requestLayout()} or {@link #invalidate()} calls.
* For example, callers can {@link #post(Runnable) post} a {@link Runnable}
* which performs a {@link #requestLayout()} on the next frame, after all detach/attach
* calls are finished, causing layout to be run prior to redrawing the view hierarchy.
*
* This method should be called only for views which were detached from their parent.
*
* @param child the child to attach
* @param index the index at which the child should be attached
* @param params the layout parameters of the child
*
* @see #removeDetachedView(View, boolean)
* @see #detachAllViewsFromParent()
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
*/
protected void attachViewToParent(View child, int index, LayoutParams params) {
child.mLayoutParams = params;
if (index < 0) {
index = mChildrenCount;
}
addInArray(child, index);
child.mParent = this;
child.mPrivateFlags = (child.mPrivateFlags & ~PFLAG_DIRTY_MASK
& ~PFLAG_DRAWING_CACHE_VALID)
| PFLAG_DRAWN | PFLAG_INVALIDATED;
this.mPrivateFlags |= PFLAG_INVALIDATED;
if (child.hasFocus()) {
requestChildFocus(child, child.findFocus());
}
}
/**
* Detaches a view from its parent. Detaching a view should be followed
* either by a call to
* {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. Detachment should only be
* temporary; reattachment or removal should happen within the same drawing cycle as
* detachment. When a view is detached, its parent is null and cannot be retrieved by a
* call to {@link #getChildAt(int)}.
*
* @param child the child to detach
*
* @see #detachViewFromParent(int)
* @see #detachViewsFromParent(int, int)
* @see #detachAllViewsFromParent()
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachViewFromParent(View child) {
removeFromArray(indexOfChild(child));
}
/**
* Detaches a view from its parent. Detaching a view should be followed
* either by a call to
* {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. Detachment should only be
* temporary; reattachment or removal should happen within the same drawing cycle as
* detachment. When a view is detached, its parent is null and cannot be retrieved by a
* call to {@link #getChildAt(int)}.
*
* @param index the index of the child to detach
*
* @see #detachViewFromParent(View)
* @see #detachAllViewsFromParent()
* @see #detachViewsFromParent(int, int)
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachViewFromParent(int index) {
removeFromArray(index);
}
/**
* Detaches a range of views from their parents. Detaching a view should be followed
* either by a call to
* {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. Detachment should only be
* temporary; reattachment or removal should happen within the same drawing cycle as
* detachment. When a view is detached, its parent is null and cannot be retrieved by a
* call to {@link #getChildAt(int)}.
*
* @param start the first index of the childrend range to detach
* @param count the number of children to detach
*
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
* @see #detachAllViewsFromParent()
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachViewsFromParent(int start, int count) {
removeFromArray(start, count);
}
/**
* Detaches all views from the parent. Detaching a view should be followed
* either by a call to
* {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. Detachment should only be
* temporary; reattachment or removal should happen within the same drawing cycle as
* detachment. When a view is detached, its parent is null and cannot be retrieved by a
* call to {@link #getChildAt(int)}.
*
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
* @see #detachViewsFromParent(int, int)
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachAllViewsFromParent() {
final int count = mChildrenCount;
if (count <= 0) {
return;
}
final View[] children = mChildren;
mChildrenCount = 0;
for (int i = count - 1; i >= 0; i--) {
children[i].mParent = null;
children[i] = null;
}
}
/**
* Don't call or override this method. It is used for the implementation of
* the view hierarchy.
*/
public final void invalidateChild(View child, final Rect dirty) {
ViewParent parent = this;
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
// If the child is drawing an animation, we want to copy this flag onto
// ourselves and the parent to make sure the invalidate request goes
// through
final boolean drawAnimation = (child.mPrivateFlags & PFLAG_DRAW_ANIMATION)
== PFLAG_DRAW_ANIMATION;
// Check whether the child that requests the invalidate is fully opaque
// Views being animated or transformed are not considered opaque because we may
// be invalidating their old position and need the parent to paint behind them.
Matrix childMatrix = child.getMatrix();
final boolean isOpaque = child.isOpaque() && !drawAnimation &&
child.getAnimation() == null && childMatrix.isIdentity();
// Mark the child as dirty, using the appropriate flag
// Make sure we do not set both flags at the same time
int opaqueFlag = isOpaque ? PFLAG_DIRTY_OPAQUE : PFLAG_DIRTY;
if (child.mLayerType != LAYER_TYPE_NONE) {
mPrivateFlags |= PFLAG_INVALIDATED;
mPrivateFlags &= ~PFLAG_DRAWING_CACHE_VALID;
child.mLocalDirtyRect.union(dirty);
}
final int[] location = attachInfo.mInvalidateChildLocation;
location[CHILD_LEFT_INDEX] = child.mLeft;
location[CHILD_TOP_INDEX] = child.mTop;
if (!childMatrix.isIdentity() ||
(mGroupFlags & ViewGroup.FLAG_SUPPORT_STATIC_TRANSFORMATIONS) != 0) {
RectF boundingRect = attachInfo.mTmpTransformRect;
boundingRect.set(dirty);
Matrix transformMatrix;
if ((mGroupFlags & ViewGroup.FLAG_SUPPORT_STATIC_TRANSFORMATIONS) != 0) {
Transformation t = attachInfo.mTmpTransformation;
boolean transformed = getChildStaticTransformation(child, t);
if (transformed) {
transformMatrix = attachInfo.mTmpMatrix;
transformMatrix.set(t.getMatrix());
if (!childMatrix.isIdentity()) {
transformMatrix.preConcat(childMatrix);
}
} else {
transformMatrix = childMatrix;
}
} else {
transformMatrix = childMatrix;
}
transformMatrix.mapRect(boundingRect);
dirty.set((int) (boundingRect.left - 0.5f),
(int) (boundingRect.top - 0.5f),
(int) (boundingRect.right + 0.5f),
(int) (boundingRect.bottom + 0.5f));
}
do {
View view = null;
if (parent instanceof View) {
view = (View) parent;
}
if (drawAnimation) {
if (view != null) {
view.mPrivateFlags |= PFLAG_DRAW_ANIMATION;
} else if (parent instanceof ViewRootImpl) {
((ViewRootImpl) parent).mIsAnimating = true;
}
}
// If the parent is dirty opaque or not dirty, mark it dirty with the opaque
// flag coming from the child that initiated the invalidate
if (view != null) {
if ((view.mViewFlags & FADING_EDGE_MASK) != 0 &&
view.getSolidColor() == 0) {
opaqueFlag = PFLAG_DIRTY;
}
if ((view.mPrivateFlags & PFLAG_DIRTY_MASK) != PFLAG_DIRTY) {
view.mPrivateFlags = (view.mPrivateFlags & ~PFLAG_DIRTY_MASK) | opaqueFlag;
}
}
parent = parent.invalidateChildInParent(location, dirty);
if (view != null) {
// Account for transform on current parent
Matrix m = view.getMatrix();
if (!m.isIdentity()) {
RectF boundingRect = attachInfo.mTmpTransformRect;
boundingRect.set(dirty);
m.mapRect(boundingRect);
dirty.set((int) (boundingRect.left - 0.5f),
(int) (boundingRect.top - 0.5f),
(int) (boundingRect.right + 0.5f),
(int) (boundingRect.bottom + 0.5f));
}
}
} while (parent != null);
}
}
/**
* Don't call or override this method. It is used for the implementation of
* the view hierarchy.
*
* This implementation returns null if this ViewGroup does not have a parent,
* if this ViewGroup is already fully invalidated or if the dirty rectangle
* does not intersect with this ViewGroup's bounds.
*/
public ViewParent invalidateChildInParent(final int[] location, final Rect dirty) {
if ((mPrivateFlags & PFLAG_DRAWN) == PFLAG_DRAWN ||
(mPrivateFlags & PFLAG_DRAWING_CACHE_VALID) == PFLAG_DRAWING_CACHE_VALID) {
if ((mGroupFlags & (FLAG_OPTIMIZE_INVALIDATE | FLAG_ANIMATION_DONE)) !=
FLAG_OPTIMIZE_INVALIDATE) {
dirty.offset(location[CHILD_LEFT_INDEX] - mScrollX,
location[CHILD_TOP_INDEX] - mScrollY);
if ((mGroupFlags & FLAG_CLIP_CHILDREN) == 0) {
dirty.union(0, 0, mRight - mLeft, mBottom - mTop);
}
final int left = mLeft;
final int top = mTop;
if ((mGroupFlags & FLAG_CLIP_CHILDREN) == FLAG_CLIP_CHILDREN) {
if (!dirty.intersect(0, 0, mRight - left, mBottom - top)) {
dirty.setEmpty();
}
}
mPrivateFlags &= ~PFLAG_DRAWING_CACHE_VALID;
location[CHILD_LEFT_INDEX] = left;
location[CHILD_TOP_INDEX] = top;
if (mLayerType != LAYER_TYPE_NONE) {
mPrivateFlags |= PFLAG_INVALIDATED;
mLocalDirtyRect.union(dirty);
}
return mParent;
} else {
mPrivateFlags &= ~PFLAG_DRAWN & ~PFLAG_DRAWING_CACHE_VALID;
location[CHILD_LEFT_INDEX] = mLeft;
location[CHILD_TOP_INDEX] = mTop;
if ((mGroupFlags & FLAG_CLIP_CHILDREN) == FLAG_CLIP_CHILDREN) {
dirty.set(0, 0, mRight - mLeft, mBottom - mTop);
} else {
// in case the dirty rect extends outside the bounds of this container
dirty.union(0, 0, mRight - mLeft, mBottom - mTop);
}
if (mLayerType != LAYER_TYPE_NONE) {
mPrivateFlags |= PFLAG_INVALIDATED;
mLocalDirtyRect.union(dirty);
}
return mParent;
}
}
return null;
}
/**
* Quick invalidation method called by View.invalidateViewProperty. This doesn't set the
* DRAWN flags and doesn't handle the Animation logic that the default invalidation methods
* do; all we want to do here is schedule a traversal with the appropriate dirty rect.
*
* @hide
*/
public void invalidateChildFast(View child, final Rect dirty) {
ViewParent parent = this;
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
if (child.mLayerType != LAYER_TYPE_NONE) {
child.mLocalDirtyRect.union(dirty);
}
int left = child.mLeft;
int top = child.mTop;
if (!child.getMatrix().isIdentity()) {
child.transformRect(dirty);
}
do {
if (parent instanceof ViewGroup) {
ViewGroup parentVG = (ViewGroup) parent;
if (parentVG.mLayerType != LAYER_TYPE_NONE) {
// Layered parents should be recreated, not just re-issued
parentVG.invalidate();
parent = null;
} else {
parent = parentVG.invalidateChildInParentFast(left, top, dirty);
left = parentVG.mLeft;
top = parentVG.mTop;
}
} else {
// Reached the top; this calls into the usual invalidate method in
// ViewRootImpl, which schedules a traversal
final int[] location = attachInfo.mInvalidateChildLocation;
location[0] = left;
location[1] = top;
parent = parent.invalidateChildInParent(location, dirty);
}
} while (parent != null);
}
}
/**
* Quick invalidation method that simply transforms the dirty rect into the parent's
* coordinate system, pruning the invalidation if the parent has already been invalidated.
*
* @hide
*/
protected ViewParent invalidateChildInParentFast(int left, int top, final Rect dirty) {
if ((mPrivateFlags & PFLAG_DRAWN) == PFLAG_DRAWN ||
(mPrivateFlags & PFLAG_DRAWING_CACHE_VALID) == PFLAG_DRAWING_CACHE_VALID) {
dirty.offset(left - mScrollX, top - mScrollY);
if ((mGroupFlags & FLAG_CLIP_CHILDREN) == 0) {
dirty.union(0, 0, mRight - mLeft, mBottom - mTop);
}
if ((mGroupFlags & FLAG_CLIP_CHILDREN) == 0 ||
dirty.intersect(0, 0, mRight - mLeft, mBottom - mTop)) {
if (mLayerType != LAYER_TYPE_NONE) {
mLocalDirtyRect.union(dirty);
}
if (!getMatrix().isIdentity()) {
transformRect(dirty);
}
return mParent;
}
}
return null;
}
/**
* Offset a rectangle that is in a descendant's coordinate
* space into our coordinate space.
* @param descendant A descendant of this view
* @param rect A rectangle defined in descendant's coordinate space.
*/
public final void offsetDescendantRectToMyCoords(View descendant, Rect rect) {
offsetRectBetweenParentAndChild(descendant, rect, true, false);
}
/**
* Offset a rectangle that is in our coordinate space into an ancestor's
* coordinate space.
* @param descendant A descendant of this view
* @param rect A rectangle defined in descendant's coordinate space.
*/
public final void offsetRectIntoDescendantCoords(View descendant, Rect rect) {
offsetRectBetweenParentAndChild(descendant, rect, false, false);
}
/**
* Helper method that offsets a rect either from parent to descendant or
* descendant to parent.
*/
void offsetRectBetweenParentAndChild(View descendant, Rect rect,
boolean offsetFromChildToParent, boolean clipToBounds) {
// already in the same coord system :)
if (descendant == this) {
return;
}
ViewParent theParent = descendant.mParent;
// search and offset up to the parent
while ((theParent != null)
&& (theParent instanceof View)
&& (theParent != this)) {
if (offsetFromChildToParent) {
rect.offset(descendant.mLeft - descendant.mScrollX,
descendant.mTop - descendant.mScrollY);
if (clipToBounds) {
View p = (View) theParent;
rect.intersect(0, 0, p.mRight - p.mLeft, p.mBottom - p.mTop);
}
} else {
if (clipToBounds) {
View p = (View) theParent;
rect.intersect(0, 0, p.mRight - p.mLeft, p.mBottom - p.mTop);
}
rect.offset(descendant.mScrollX - descendant.mLeft,
descendant.mScrollY - descendant.mTop);
}
descendant = (View) theParent;
theParent = descendant.mParent;
}
// now that we are up to this view, need to offset one more time
// to get into our coordinate space
if (theParent == this) {
if (offsetFromChildToParent) {
rect.offset(descendant.mLeft - descendant.mScrollX,
descendant.mTop - descendant.mScrollY);
} else {
rect.offset(descendant.mScrollX - descendant.mLeft,
descendant.mScrollY - descendant.mTop);
}
} else {
/* SPRD: in the state of monkey test, due to the fast operation, parent has been
* destroyed before drawing the child ,so this case occur @{ */
if (android.os.Debug.isMonkey()) {
Log.e(TAG, "parameter must be a descendant of this view, theParent: "
+ theParent + ",this: " + this);
rect.set(-1, -1, -1, -1);
/* @} */
} else {
throw new IllegalArgumentException("parameter must be a descendant of this view");
}
}
}
/**
* Offset the vertical location of all children of this view by the specified number of pixels.
*
* @param offset the number of pixels to offset
*
* @hide
*/
public void offsetChildrenTopAndBottom(int offset) {
final int count = mChildrenCount;
final View[] children = mChildren;
boolean invalidate = false;
for (int i = 0; i < count; i++) {
final View v = children[i];
v.mTop += offset;
v.mBottom += offset;
if (v.mDisplayList != null) {
invalidate = true;
v.mDisplayList.offsetTopAndBottom(offset);
}
}
if (invalidate) {
invalidateViewProperty(false, false);
}
}
/**
* {@inheritDoc}
*/
public boolean getChildVisibleRect(View child, Rect r, android.graphics.Point offset) {
// It doesn't make a whole lot of sense to call this on a view that isn't attached,
// but for some simple tests it can be useful. If we don't have attach info this
// will allocate memory.
final RectF rect = mAttachInfo != null ? mAttachInfo.mTmpTransformRect : new RectF();
rect.set(r);
if (!child.hasIdentityMatrix()) {
child.getMatrix().mapRect(rect);
}
int dx = child.mLeft - mScrollX;
int dy = child.mTop - mScrollY;
rect.offset(dx, dy);
if (offset != null) {
if (!child.hasIdentityMatrix()) {
float[] position = mAttachInfo != null ? mAttachInfo.mTmpTransformLocation
: new float[2];
position[0] = offset.x;
position[1] = offset.y;
child.getMatrix().mapPoints(position);
offset.x = (int) (position[0] + 0.5f);
offset.y = (int) (position[1] + 0.5f);
}
offset.x += dx;
offset.y += dy;
}
if (rect.intersect(0, 0, mRight - mLeft, mBottom - mTop)) {
if (mParent == null) return true;
r.set((int) (rect.left + 0.5f), (int) (rect.top + 0.5f),
(int) (rect.right + 0.5f), (int) (rect.bottom + 0.5f));
return mParent.getChildVisibleRect(this, r, offset);
}
return false;
}
/**
* {@inheritDoc}
*/
@Override
public final void layout(int l, int t, int r, int b) {
if (!mSuppressLayout && (mTransition == null || !mTransition.isChangingLayout())) {
if (mTransition != null) {
mTransition.layoutChange(this);
}
super.layout(l, t, r, b);
} else {
// record the fact that we noop'd it; request layout when transition finishes
mLayoutCalledWhileSuppressed = true;
}
}
/**
* {@inheritDoc}
*/
@Override
//onLayout是一个抽像函数，要求实现ViewGroup的函数必须实现这个函数，这也就是ViewGroup是一个抽像函数的原因。因为各种组件实现的布局方式不一样
protected abstract void onLayout(boolean changed,
int l, int t, int r, int b);
/**
* Indicates whether the view group has the ability to animate its children
* after the first layout.
*
* @return true if the children can be animated, false otherwise
*/
protected boolean canAnimate() {
return mLayoutAnimationController != null;
}
/**
* Runs the layout animation. Calling this method triggers a relayout of
* this view group.
*/
public void startLayoutAnimation() {
if (mLayoutAnimationController != null) {
mGroupFlags |= FLAG_RUN_ANIMATION;
requestLayout();
}
}
/**
* Schedules the layout animation to be played after the next layout pass
* of this view group. This can be used to restart the layout animation
* when the content of the view group changes or when the activity is
* paused and resumed.
*/
public void scheduleLayoutAnimation() {
mGroupFlags |= FLAG_RUN_ANIMATION;
}
/**
* Sets the layout animation controller used to animate the group's
* children after the first layout.
*
* @param controller the animation controller
*/
public void setLayoutAnimation(LayoutAnimationController controller) {
mLayoutAnimationController = controller;
if (mLayoutAnimationController != null) {
mGroupFlags |= FLAG_RUN_ANIMATION;
}
}
/**
* Returns the layout animation controller used to animate the group's
* children.
*
* @return the current animation controller
*/
public LayoutAnimationController getLayoutAnimation() {
return mLayoutAnimationController;
}
/**
* Indicates whether the children's drawing cache is used during a layout
* animation. By default, the drawing cache is enabled but this will prevent
* nested layout animations from working. To nest animations, you must disable
* the cache.
*
* @return true if the animation cache is enabled, false otherwise
*
* @see #setAnimationCacheEnabled(boolean)
* @see View#setDrawingCacheEnabled(boolean)
*/
@ViewDebug.ExportedProperty
public boolean isAnimationCacheEnabled() {
return (mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE;
}
/**
* Enables or disables the children's drawing cache during a layout animation.
* By default, the drawing cache is enabled but this will prevent nested
* layout animations from working. To nest animations, you must disable the
* cache.
*
* @param enabled true to enable the animation cache, false otherwise
*
* @see #isAnimationCacheEnabled()
* @see View#setDrawingCacheEnabled(boolean)
*/
public void setAnimationCacheEnabled(boolean enabled) {
setBooleanFlag(FLAG_ANIMATION_CACHE, enabled);
}
/**
* Indicates whether this ViewGroup will always try to draw its children using their
* drawing cache. By default this property is enabled.
*
* @return true if the animation cache is enabled, false otherwise
*
* @see #setAlwaysDrawnWithCacheEnabled(boolean)
* @see #setChildrenDrawnWithCacheEnabled(boolean)
* @see View#setDrawingCacheEnabled(boolean)
*/
@ViewDebug.ExportedProperty(category = "drawing")
public boolean isAlwaysDrawnWithCacheEnabled() {
return (mGroupFlags & FLAG_ALWAYS_DRAWN_WITH_CACHE) == FLAG_ALWAYS_DRAWN_WITH_CACHE;
}
/**
* Indicates whether this ViewGroup will always try to draw its children using their
* drawing cache. This property can be set to true when the cache rendering is
* slightly different from the children's normal rendering. Renderings can be different,
* for instance, when the cache's quality is set to low.
*
* When this property is disabled, the ViewGroup will use the drawing cache of its
* children only when asked to. It's usually the task of subclasses to tell ViewGroup
* when to start using the drawing cache and when to stop using it.
*
* @param always true to always draw with the drawing cache, false otherwise
*
* @see #isAlwaysDrawnWithCacheEnabled()
* @see #setChildrenDrawnWithCacheEnabled(boolean)
* @see View#setDrawingCacheEnabled(boolean)
* @see View#setDrawingCacheQuality(int)
*/
public void setAlwaysDrawnWithCacheEnabled(boolean always) {
setBooleanFlag(FLAG_ALWAYS_DRAWN_WITH_CACHE, always);
}
/**
* Indicates whether the ViewGroup is currently drawing its children using
* their drawing cache.
*
* @return true if children should be drawn with their cache, false otherwise
*
* @see #setAlwaysDrawnWithCacheEnabled(boolean)
* @see #setChildrenDrawnWithCacheEnabled(boolean)
*/
@ViewDebug.ExportedProperty(category = "drawing")
protected boolean isChildrenDrawnWithCacheEnabled() {
return (mGroupFlags & FLAG_CHILDREN_DRAWN_WITH_CACHE) == FLAG_CHILDREN_DRAWN_WITH_CACHE;
}
/**
* Tells the ViewGroup to draw its children using their drawing cache. This property
* is ignored when {@link #isAlwaysDrawnWithCacheEnabled()} is true. A child's drawing cache
* will be used only if it has been enabled.
*
* Subclasses should call this method to start and stop using the drawing cache when
* they perform performance sensitive operations, like scrolling or animating.
*
* @param enabled true if children should be drawn with their cache, false otherwise
*
* @see #setAlwaysDrawnWithCacheEnabled(boolean)
* @see #isChildrenDrawnWithCacheEnabled()
*/
protected void setChildrenDrawnWithCacheEnabled(boolean enabled) {
setBooleanFlag(FLAG_CHILDREN_DRAWN_WITH_CACHE, enabled);
}
/**
* Indicates whether the ViewGroup is drawing its children in the order defined by
* {@link #getChildDrawingOrder(int, int)}.
*
* @return true if children drawing order is defined by {@link #getChildDrawingOrder(int, int)},
* false otherwise
*
* @see #setChildrenDrawingOrderEnabled(boolean)
* @see #getChildDrawingOrder(int, int)
*/
@ViewDebug.ExportedProperty(category = "drawing")
protected boolean isChildrenDrawingOrderEnabled() {
return (mGroupFlags & FLAG_USE_CHILD_DRAWING_ORDER) == FLAG_USE_CHILD_DRAWING_ORDER;
}
/**
* Tells the ViewGroup whether to draw its children in the order defined by the method
* {@link #getChildDrawingOrder(int, int)}.
*
* @param enabled true if the order of the children when drawing is determined by
* {@link #getChildDrawingOrder(int, int)}, false otherwise
*
* @see #isChildrenDrawingOrderEnabled()
* @see #getChildDrawingOrder(int, int)
*/
protected void setChildrenDrawingOrderEnabled(boolean enabled) {
setBooleanFlag(FLAG_USE_CHILD_DRAWING_ORDER, enabled);
}
private boolean hasBooleanFlag(int flag) {
return (mGroupFlags & flag) == flag;
}
private void setBooleanFlag(int flag, boolean value) {
if (value) {
mGroupFlags |= flag;
} else {
mGroupFlags &= ~flag;
}
}
/**
* Returns an integer indicating what types of drawing caches are kept in memory.
*
* @see #setPersistentDrawingCache(int)
* @see #setAnimationCacheEnabled(boolean)
*
* @return one or a combination of {@link #PERSISTENT_NO_CACHE},
* {@link #PERSISTENT_ANIMATION_CACHE}, {@link #PERSISTENT_SCROLLING_CACHE}
* and {@link #PERSISTENT_ALL_CACHES}
*/
@ViewDebug.ExportedProperty(category = "drawing", mapping = {
@ViewDebug.IntToString(from = PERSISTENT_NO_CACHE, to = "NONE"),
@ViewDebug.IntToString(from = PERSISTENT_ANIMATION_CACHE, to = "ANIMATION"),
@ViewDebug.IntToString(from = PERSISTENT_SCROLLING_CACHE, to = "SCROLLING"),
@ViewDebug.IntToString(from = PERSISTENT_ALL_CACHES, to = "ALL")
})
public int getPersistentDrawingCache() {
return mPersistentDrawingCache;
}
/**
* Indicates what types of drawing caches should be kept in memory after
* they have been created.
*
* @see #getPersistentDrawingCache()
* @see #setAnimationCacheEnabled(boolean)
*
* @param drawingCacheToKeep one or a combination of {@link #PERSISTENT_NO_CACHE},
* {@link #PERSISTENT_ANIMATION_CACHE}, {@link #PERSISTENT_SCROLLING_CACHE}
* and {@link #PERSISTENT_ALL_CACHES}
*/
public void setPersistentDrawingCache(int drawingCacheToKeep) {
mPersistentDrawingCache = drawingCacheToKeep & PERSISTENT_ALL_CACHES;
}
private void setLayoutMode(int layoutMode, boolean explicitly) {
mLayoutMode = layoutMode;
setBooleanFlag(FLAG_LAYOUT_MODE_WAS_EXPLICITLY_SET, explicitly);
}
/**
* Recursively traverse the view hierarchy, resetting the layoutMode of any
* descendants that had inherited a different layoutMode from a previous parent.
* Recursion terminates when a descendant's mode is:
*
*
Undefined
*
The same as the root node's
*
A mode that had been explicitly set
*
* The first two clauses are optimizations.
* @param layoutModeOfRoot
*/
@Override
void invalidateInheritedLayoutMode(int layoutModeOfRoot) {
if (mLayoutMode == LAYOUT_MODE_UNDEFINED ||
mLayoutMode == layoutModeOfRoot ||
hasBooleanFlag(FLAG_LAYOUT_MODE_WAS_EXPLICITLY_SET)) {
return;
}
setLayoutMode(LAYOUT_MODE_UNDEFINED, false);
// apply recursively
for (int i = 0, N = getChildCount(); i < N; i++) {
getChildAt(i).invalidateInheritedLayoutMode(layoutModeOfRoot);
}
}
/**
* Returns the basis of alignment during layout operations on this ViewGroup:
* either {@link #LAYOUT_MODE_CLIP_BOUNDS} or {@link #LAYOUT_MODE_OPTICAL_BOUNDS}.
*
* If no layoutMode was explicitly set, either programmatically or in an XML resource,
* the method returns the layoutMode of the view's parent ViewGroup if such a parent exists,
* otherwise the method returns a default value of {@link #LAYOUT_MODE_CLIP_BOUNDS}.
*
* @return the layout mode to use during layout operations
*
* @see #setLayoutMode(int)
*/
public int getLayoutMode() {
if (mLayoutMode == LAYOUT_MODE_UNDEFINED) {
int inheritedLayoutMode = (mParent instanceof ViewGroup) ?
((ViewGroup) mParent).getLayoutMode() : LAYOUT_MODE_DEFAULT;
setLayoutMode(inheritedLayoutMode, false);
}
return mLayoutMode;
}
/**
* Sets the basis of alignment during the layout of this ViewGroup.
* Valid values are either {@link #LAYOUT_MODE_CLIP_BOUNDS} or
* {@link #LAYOUT_MODE_OPTICAL_BOUNDS}.
*
* @param layoutMode the layout mode to use during layout operations
*
* @see #getLayoutMode()
* @attr ref android.R.styleable#ViewGroup_layoutMode
*/
public void setLayoutMode(int layoutMode) {
if (mLayoutMode != layoutMode) {
invalidateInheritedLayoutMode(layoutMode);
setLayoutMode(layoutMode, layoutMode != LAYOUT_MODE_UNDEFINED);
requestLayout();
}
}
/**
* Returns a new set of layout parameters based on the supplied attributes set.
*
* @param attrs the attributes to build the layout parameters from
*
* @return an instance of {@link android.view.ViewGroup.LayoutParams} or one
* of its descendants
*/
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new LayoutParams(getContext(), attrs);
}
/**
* Returns a safe set of layout parameters based on the supplied layout params.
* When a ViewGroup is passed a View whose layout params do not pass the test of
* {@link #checkLayoutParams(android.view.ViewGroup.LayoutParams)}, this method
* is invoked. This method should return a new set of layout params suitable for
* this ViewGroup, possibly by copying the appropriate attributes from the
* specified set of layout params.
*
* @param p The layout parameters to convert into a suitable set of layout parameters
* for this ViewGroup.
*
* @return an instance of {@link android.view.ViewGroup.LayoutParams} or one
* of its descendants
*/
protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
return p;
}
/**
* Returns a set of default layout parameters. These parameters are requested
* when the View passed to {@link #addView(View)} has no layout parameters
* already set. If null is returned, an exception is thrown from addView.
*
* @return a set of default layout parameters or null
*/
protected LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
}
/**
* {@inheritDoc}
*/
@Override
protected void debug(int depth) {
super.debug(depth);
String output;
if (mFocused != null) {
output = debugIndent(depth);
output += "mFocused";
Log.d(VIEW_LOG_TAG, output);
}
if (mChildrenCount != 0) {
output = debugIndent(depth);
output += "{";
Log.d(VIEW_LOG_TAG, output);
}
int count = mChildrenCount;
for (int i = 0; i < count; i++) {
View child = mChildren[i];
child.debug(depth + 1);
}
if (mChildrenCount != 0) {
output = debugIndent(depth);
output += "}";
Log.d(VIEW_LOG_TAG, output);
}
}
/**
* Returns the position in the group of the specified child view.
*
* @param child the view for which to get the position
* @return a positive integer representing the position of the view in the
* group, or -1 if the view does not exist in the group
*/
public int indexOfChild(View child) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
if (children[i] == child) {
return i;
}
}
return -1;
}
/**
* Returns the number of children in the group.
*
* @return a positive integer representing the number of children in
* the group
*/
public int getChildCount() {
return mChildrenCount;
}
/**
* Returns the view at the specified position in the group.
*
* @param index the position at which to get the view from
* @return the view at the specified position or null if the position
* does not exist within the group
*/
//查询
public View getChildAt(int index) {
if (index < 0 || index >= mChildrenCount) {
return null;
}
return mChildren[index];
}
/**
* Ask all of the children of this view to measure themselves, taking into
* account both the MeasureSpec requirements for this view and its padding.
* We skip children that are in the GONE state The heavy lifting is done in
* getChildMeasureSpec.
*
* @param widthMeasureSpec The width requirements for this view
* @param heightMeasureSpec The height requirements for this view
*/
//measureChildren(int widthMeasureSpec, int heightMeasureSpec) 根据指定的高和宽来测量所有子View中显示参数 非GONE的组件
protected void measureChildren(int widthMeasureSpec, int heightMeasureSpec) {
final int size = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < size; ++i) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) != GONE) {
measureChild(child, widthMeasureSpec, heightMeasureSpec);
}
}
}
/**
* Ask one of the children of this view to measure itself, taking into
* account both the MeasureSpec requirements for this view and its padding.
* The heavy lifting is done in getChildMeasureSpec.
*
* @param child The child to measure
* @param parentWidthMeasureSpec The width requirements for this view
* @param parentHeightMeasureSpec The height requirements for this view
*/
//measureChild(View child, int parentWidthMeasureSpec,int parentHeightMeasureSpec)为子组件添加padding
protected void measureChild(View child, int parentWidthMeasureSpec,
int parentHeightMeasureSpec) {
final LayoutParams lp = child.getLayoutParams();
final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
mPaddingLeft + mPaddingRight, lp.width);
final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec,
mPaddingTop + mPaddingBottom, lp.height);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
/**
* Ask one of the children of this view to measure itself, taking into
* account both the MeasureSpec requirements for this view and its padding
* and margins. The child must have MarginLayoutParams The heavy lifting is
* done in getChildMeasureSpec.
*
* @param child The child to measure
* @param parentWidthMeasureSpec The width requirements for this view
* @param widthUsed Extra space that has been used up by the parent
* horizontally (possibly by other children of the parent)
* @param parentHeightMeasureSpec The height requirements for this view
* @param heightUsed Extra space that has been used up by the parent
* vertically (possibly by other children of the parent)
*/
//measureChildWithMargins(View child,
int parentWidthMeasureSpec, int widthUsed,
int parentHeightMeasureSpec, int heightUsed) 测量指定的子组件，为子组件添加padding和margin
protected void measureChildWithMargins(View child,
int parentWidthMeasureSpec, int widthUsed,
int parentHeightMeasureSpec, int heightUsed) {
final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin
+ widthUsed, lp.width);
final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec,
mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin
+ heightUsed, lp.height);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
/**
* Does the hard part of measureChildren: figuring out the MeasureSpec to
* pass to a particular child. This method figures out the right MeasureSpec
* for one dimension (height or width) of one child view.
*
* The goal is to combine information from our MeasureSpec with the
* LayoutParams of the child to get the best possible results. For example,
* if the this view knows its size (because its MeasureSpec has a mode of
* EXACTLY), and the child has indicated in its LayoutParams that it wants
* to be the same size as the parent, the parent should ask the child to
* layout given an exact size.
*
* @param spec The requirements for this view
* @param padding The padding of this view for the current dimension and
* margins, if applicable
* @param childDimension How big the child wants to be in the current
* dimension
* @return a MeasureSpec integer for the child
*/
public static int getChildMeasureSpec(int spec, int padding, int childDimension) {
int specMode = MeasureSpec.getMode(spec);
int specSize = MeasureSpec.getSize(spec);
int size = Math.max(0, specSize - padding);
int resultSize = 0;
int resultMode = 0;
switch (specMode) {
// Parent has imposed an exact size on us
case MeasureSpec.EXACTLY:
if (childDimension >= 0) {
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size. So be it.
resultSize = size;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent has imposed a maximum size on us
case MeasureSpec.AT_MOST:
if (childDimension >= 0) {
// Child wants a specific size... so be it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size, but our size is not fixed.
// Constrain child to not be bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent asked to see how big we want to be
case MeasureSpec.UNSPECIFIED:
if (childDimension >= 0) {
// Child wants a specific size... let him have it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size... find out how big it should
// be
resultSize = 0;
resultMode = MeasureSpec.UNSPECIFIED;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size.... find out how
// big it should be
resultSize = 0;
resultMode = MeasureSpec.UNSPECIFIED;
}
break;
}
return MeasureSpec.makeMeasureSpec(resultSize, resultMode);
}
/**
* Removes any pending animations for views that have been removed. Call
* this if you don't want animations for exiting views to stack up.
*/
public void clearDisappearingChildren() {
if (mDisappearingChildren != null) {
mDisappearingChildren.clear();
invalidate();
}
}
/**
* Add a view which is removed from mChildren but still needs animation
*
* @param v View to add
*/
private void addDisappearingView(View v) {
ArrayList disappearingChildren = mDisappearingChildren;
if (disappearingChildren == null) {
disappearingChildren = mDisappearingChildren = new ArrayList();
}
disappearingChildren.add(v);
}
/**
* Cleanup a view when its animation is done. This may mean removing it from
* the list of disappearing views.
*
* @param view The view whose animation has finished
* @param animation The animation, cannot be null
*/
void finishAnimatingView(final View view, Animation animation) {
final ArrayList disappearingChildren = mDisappearingChildren;
if (disappearingChildren != null) {
if (disappearingChildren.contains(view)) {
disappearingChildren.remove(view);
if (view.mAttachInfo != null) {
view.dispatchDetachedFromWindow();
}
view.clearAnimation();
mGroupFlags |= FLAG_INVALIDATE_REQUIRED;
}
}
if (animation != null && !animation.getFillAfter()) {
view.clearAnimation();
}
if ((view.mPrivateFlags & PFLAG_ANIMATION_STARTED) == PFLAG_ANIMATION_STARTED) {
view.onAnimationEnd();
// Should be performed by onAnimationEnd() but this avoid an infinite loop,
// so we'd rather be safe than sorry
view.mPrivateFlags &= ~PFLAG_ANIMATION_STARTED;
// Draw one more frame after the animation is done
mGroupFlags |= FLAG_INVALIDATE_REQUIRED;
}
}
/**
* Utility function called by View during invalidation to determine whether a view that
* is invisible or gone should still be invalidated because it is being transitioned (and
* therefore still needs to be drawn).
*/
boolean isViewTransitioning(View view) {
return (mTransitioningViews != null && mTransitioningViews.contains(view));
}
/**
* This method tells the ViewGroup that the given View object, which should have this
* ViewGroup as its parent,
* should be kept around (re-displayed when the ViewGroup draws its children) even if it
* is removed from its parent. This allows animations, such as those used by
* {@link android.app.Fragment} and {@link android.animation.LayoutTransition} to animate
* the removal of views. A call to this method should always be accompanied by a later call
* to {@link #endViewTransition(View)}, such as after an animation on the View has finished,
* so that the View finally gets removed.
*
* @param view The View object to be kept visible even if it gets removed from its parent.
*/
public void startViewTransition(View view) {
if (view.mParent == this) {
if (mTransitioningViews == null) {
mTransitioningViews = new ArrayList();
}
mTransitioningViews.add(view);
}
}
/**
* This method should always be called following an earlier call to
* {@link #startViewTransition(View)}. The given View is finally removed from its parent
* and will no longer be displayed. Note that this method does not perform the functionality
* of removing a view from its parent; it just discontinues the display of a View that
* has previously been removed.
*
* @return view The View object that has been removed but is being kept around in the visible
* hierarchy by an earlier call to {@link #startViewTransition(View)}.
*/
public void endViewTransition(View view) {
if (mTransitioningViews != null) {
mTransitioningViews.remove(view);
final ArrayList disappearingChildren = mDisappearingChildren;
if (disappearingChildren != null && disappearingChildren.contains(view)) {
disappearingChildren.remove(view);
if (mVisibilityChangingChildren != null &&
mVisibilityChangingChildren.contains(view)) {
mVisibilityChangingChildren.remove(view);
} else {
if (view.mAttachInfo != null) {
view.dispatchDetachedFromWindow();
}
if (view.mParent != null) {
view.mParent = null;
}
}
invalidate();
}
}
}
private LayoutTransition.TransitionListener mLayoutTransitionListener =
new LayoutTransition.TransitionListener() {
@Override
public void startTransition(LayoutTransition transition, ViewGroup container,
View view, int transitionType) {
// We only care about disappearing items, since we need special logic to keep
// those items visible after they've been 'removed'
if (transitionType == LayoutTransition.DISAPPEARING) {
startViewTransition(view);
}
}
@Override
public void endTransition(LayoutTransition transition, ViewGroup container,
View view, int transitionType) {
if (mLayoutCalledWhileSuppressed && !transition.isChangingLayout()) {
requestLayout();
mLayoutCalledWhileSuppressed = false;
}
if (transitionType == LayoutTransition.DISAPPEARING && mTransitioningViews != null) {
endViewTransition(view);
}
}
};
/**
* Tells this ViewGroup to suppress all layout() calls until layout
* suppression is disabled with a later call to suppressLayout(false).
* When layout suppression is disabled, a requestLayout() call is sent
* if layout() was attempted while layout was being suppressed.
*
* @hide
*/
public void suppressLayout(boolean suppress) {
mSuppressLayout = suppress;
if (!suppress) {
if (mLayoutCalledWhileSuppressed) {
requestLayout();
mLayoutCalledWhileSuppressed = false;
}
}
}
/**
* Returns whether layout calls on this container are currently being
* suppressed, due to an earlier call to {@link #suppressLayout(boolean)}.
*
* @return true if layout calls are currently suppressed, false otherwise.
*
* @hide
*/
public boolean isLayoutSuppressed() {
return mSuppressLayout;
}
/**
* {@inheritDoc}
*/
@Override
public boolean gatherTransparentRegion(Region region) {
// If no transparent regions requested, we are always opaque.
final boolean meOpaque = (mPrivateFlags & View.PFLAG_REQUEST_TRANSPARENT_REGIONS) == 0;
if (meOpaque && region == null) {
// The caller doesn't care about the region, so stop now.
return true;
}
super.gatherTransparentRegion(region);
final View[] children = mChildren;
final int count = mChildrenCount;
boolean noneOfTheChildrenAreTransparent = true;
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE || child.getAnimation() != null) {
if (!child.gatherTransparentRegion(region)) {
noneOfTheChildrenAreTransparent = false;
}
}
}
return meOpaque || noneOfTheChildrenAreTransparent;
}
/**
* {@inheritDoc}
*/
public void requestTransparentRegion(View child) {
if (child != null) {
child.mPrivateFlags |= View.PFLAG_REQUEST_TRANSPARENT_REGIONS;
if (mParent != null) {
mParent.requestTransparentRegion(this);
}
}
}
@Override
protected boolean fitSystemWindows(Rect insets) {
boolean done = super.fitSystemWindows(insets);
if (!done) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
done = children[i].fitSystemWindows(insets);
if (done) {
break;
}
}
}
return done;
}
/**
* Returns the animation listener to which layout animation events are
* sent.
*
* @return an {@link android.view.animation.Animation.AnimationListener}
*/
public Animation.AnimationListener getLayoutAnimationListener() {
return mAnimationListener;
}
@Override
protected void drawableStateChanged() {
super.drawableStateChanged();
if ((mGroupFlags & FLAG_NOTIFY_CHILDREN_ON_DRAWABLE_STATE_CHANGE) != 0) {
if ((mGroupFlags & FLAG_ADD_STATES_FROM_CHILDREN) != 0) {
throw new IllegalStateException("addStateFromChildren cannot be enabled if a"
+ " child has duplicateParentState set to true");
}
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
final View child = children[i];
if ((child.mViewFlags & DUPLICATE_PARENT_STATE) != 0) {
child.refreshDrawableState();
}
}
}
}
@Override
public void jumpDrawablesToCurrentState() {
super.jumpDrawablesToCurrentState();
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].jumpDrawablesToCurrentState();
}
}
@Override
protected int[] onCreateDrawableState(int extraSpace) {
if ((mGroupFlags & FLAG_ADD_STATES_FROM_CHILDREN) == 0) {
return super.onCreateDrawableState(extraSpace);
}
int need = 0;
int n = getChildCount();
for (int i = 0; i < n; i++) {
int[] childState = getChildAt(i).getDrawableState();
if (childState != null) {
need += childState.length;
}
}
int[] state = super.onCreateDrawableState(extraSpace + need);
for (int i = 0; i < n; i++) {
int[] childState = getChildAt(i).getDrawableState();
if (childState != null) {
state = mergeDrawableStates(state, childState);
}
}
return state;
}
/**
* Sets whether this ViewGroup's drawable states also include
* its children's drawable states. This is used, for example, to
* make a group appear to be focused when its child EditText or button
* is focused.
*/
public void setAddStatesFromChildren(boolean addsStates) {
if (addsStates) {
mGroupFlags |= FLAG_ADD_STATES_FROM_CHILDREN;
} else {
mGroupFlags &= ~FLAG_ADD_STATES_FROM_CHILDREN;
}
refreshDrawableState();
}
/**
* Returns whether this ViewGroup's drawable states also include
* its children's drawable states. This is used, for example, to
* make a group appear to be focused when its child EditText or button
* is focused.
*/
public boolean addStatesFromChildren() {
return (mGroupFlags & FLAG_ADD_STATES_FROM_CHILDREN) != 0;
}
/**
* If {@link #addStatesFromChildren} is true, refreshes this group's
* drawable state (to include the states from its children).
*/
public void childDrawableStateChanged(View child) {
if ((mGroupFlags & FLAG_ADD_STATES_FROM_CHILDREN) != 0) {
refreshDrawableState();
}
}
/**
* Specifies the animation listener to which layout animation events must
* be sent. Only
* {@link android.view.animation.Animation.AnimationListener#onAnimationStart(Animation)}
* and
* {@link android.view.animation.Animation.AnimationListener#onAnimationEnd(Animation)}
* are invoked.
*
* @param animationListener the layout animation listener
*/
public void setLayoutAnimationListener(Animation.AnimationListener animationListener) {
mAnimationListener = animationListener;
}
/**
* This method is called by LayoutTransition when there are 'changing' animations that need
* to start after the layout/setup phase. The request is forwarded to the ViewAncestor, who
* starts all pending transitions prior to the drawing phase in the current traversal.
*
* @param transition The LayoutTransition to be started on the next traversal.
*
* @hide
*/
public void requestTransitionStart(LayoutTransition transition) {
ViewRootImpl viewAncestor = getViewRootImpl();
if (viewAncestor != null) {
viewAncestor.requestTransitionStart(transition);
}
}
/**
* @hide
*/
@Override
public boolean resolveRtlPropertiesIfNeeded() {
final boolean result = super.resolveRtlPropertiesIfNeeded();
// We dont need to resolve the children RTL properties if nothing has changed for the parent
if (result) {
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resolveRtlPropertiesIfNeeded();
}
}
}
return result;
}
/**
* @hide
*/
@Override
public boolean resolveLayoutDirection() {
final boolean result = super.resolveLayoutDirection();
if (result) {
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resolveLayoutDirection();
}
}
}
return result;
}
/**
* @hide
*/
@Override
public boolean resolveTextDirection() {
final boolean result = super.resolveTextDirection();
if (result) {
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isTextDirectionInherited()) {
child.resolveTextDirection();
}
}
}
return result;
}
/**
* @hide
*/
@Override
public boolean resolveTextAlignment() {
final boolean result = super.resolveTextAlignment();
if (result) {
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isTextAlignmentInherited()) {
child.resolveTextAlignment();
}
}
}
return result;
}
/**
* @hide
*/
@Override
public void resolvePadding() {
super.resolvePadding();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resolvePadding();
}
}
}
/**
* @hide
*/
@Override
protected void resolveDrawables() {
super.resolveDrawables();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resolveDrawables();
}
}
}
/**
* @hide
*/
@Override
public void resolveLayoutParams() {
super.resolveLayoutParams();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
child.resolveLayoutParams();
}
}
/**
* @hide
*/
@Override
public void resetResolvedLayoutDirection() {
super.resetResolvedLayoutDirection();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resetResolvedLayoutDirection();
}
}
}
/**
* @hide
*/
@Override
public void resetResolvedTextDirection() {
super.resetResolvedTextDirection();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isTextDirectionInherited()) {
child.resetResolvedTextDirection();
}
}
}
/**
* @hide
*/
@Override
public void resetResolvedTextAlignment() {
super.resetResolvedTextAlignment();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isTextAlignmentInherited()) {
child.resetResolvedTextAlignment();
}
}
}
/**
* @hide
*/
@Override
public void resetResolvedPadding() {
super.resetResolvedPadding();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resetResolvedPadding();
}
}
}
/**
* @hide
*/
@Override
protected void resetResolvedDrawables() {
super.resetResolvedDrawables();
int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.isLayoutDirectionInherited()) {
child.resetResolvedDrawables();
}
}
}
/**
* Return true if the pressed state should be delayed for children or descendants of this
* ViewGroup. Generally, this should be done for containers that can scroll, such as a List.
* This prevents the pressed state from appearing when the user is actually trying to scroll
* the content.
*
* The default implementation returns true for compatibility reasons. Subclasses that do
* not scroll should generally override this method and return false.
*/
public boolean shouldDelayChildPressedState() {
return true;
}
/** @hide */
protected void onSetLayoutParams(View child, LayoutParams layoutParams) {
}
/**
* LayoutParams are used by views to tell their parents how they want to be
* laid out. See
* {@link android.R.styleable#ViewGroup_Layout ViewGroup Layout Attributes}
* for a list of all child view attributes that this class supports.
*
*
* The base LayoutParams class just describes how big the view wants to be
* for both width and height. For each dimension, it can specify one of:
*
*
FILL_PARENT (renamed MATCH_PARENT in API Level 8 and higher), which
* means that the view wants to be as big as its parent (minus padding)
*
WRAP_CONTENT, which means that the view wants to be just big enough
* to enclose its content (plus padding)
*
an exact number
*
* There are subclasses of LayoutParams for different subclasses of
* ViewGroup. For example, AbsoluteLayout has its own subclass of
* LayoutParams which adds an X and Y value.
*
*
*
Developer Guides
*
For more information about creating user interface layouts, read the
* XML Layouts developer
* guide.
*
* @attr ref android.R.styleable#ViewGroup_Layout_layout_height
* @attr ref android.R.styleable#ViewGroup_Layout_layout_width
*/
public static class LayoutParams {
/**
* Special value for the height or width requested by a View.
* FILL_PARENT means that the view wants to be as big as its parent,
* minus the parent's padding, if any. This value is deprecated
* starting in API Level 8 and replaced by {@link #MATCH_PARENT}.
*/
@SuppressWarnings({"UnusedDeclaration"})
@Deprecated
public static final int FILL_PARENT = -1;
/**
* Special value for the height or width requested by a View.
* MATCH_PARENT means that the view wants to be as big as its parent,
* minus the parent's padding, if any. Introduced in API Level 8.
*/
public static final int MATCH_PARENT = -1;
/**
* Special value for the height or width requested by a View.
* WRAP_CONTENT means that the view wants to be just large enough to fit
* its own internal content, taking its own padding into account.
*/
public static final int WRAP_CONTENT = -2;
/**
* Information about how wide the view wants to be. Can be one of the
* constants FILL_PARENT (replaced by MATCH_PARENT ,
* in API Level 8) or WRAP_CONTENT. or an exact size.
*/
@ViewDebug.ExportedProperty(category = "layout", mapping = {
@ViewDebug.IntToString(from = MATCH_PARENT, to = "MATCH_PARENT"),
@ViewDebug.IntToString(from = WRAP_CONTENT, to = "WRAP_CONTENT")
})
public int width;
/**
* Information about how tall the view wants to be. Can be one of the
* constants FILL_PARENT (replaced by MATCH_PARENT ,
* in API Level 8) or WRAP_CONTENT. or an exact size.
*/
@ViewDebug.ExportedProperty(category = "layout", mapping = {
@ViewDebug.IntToString(from = MATCH_PARENT, to = "MATCH_PARENT"),
@ViewDebug.IntToString(from = WRAP_CONTENT, to = "WRAP_CONTENT")
})
public int height;
/**
* Used to animate layouts.
*/
public LayoutAnimationController.AnimationParameters layoutAnimationParameters;
/**
* Creates a new set of layout parameters. The values are extracted from
* the supplied attributes set and context. The XML attributes mapped
* to this set of layout parameters are:
*
*
*
layout_width: the width, either an exact value,
* {@link #WRAP_CONTENT}, or {@link #FILL_PARENT} (replaced by
* {@link #MATCH_PARENT} in API Level 8)
*
layout_height: the height, either an exact value,
* {@link #WRAP_CONTENT}, or {@link #FILL_PARENT} (replaced by
* {@link #MATCH_PARENT} in API Level 8)
*
*
* @param c the application environment
* @param attrs the set of attributes from which to extract the layout
* parameters' values
*/
public LayoutParams(Context c, AttributeSet attrs) {
TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.ViewGroup_Layout);
setBaseAttributes(a,
R.styleable.ViewGroup_Layout_layout_width,
R.styleable.ViewGroup_Layout_layout_height);
a.recycle();
}
/**
* Creates a new set of layout parameters with the specified width
* and height.
*
* @param width the width, either {@link #WRAP_CONTENT},
* {@link #FILL_PARENT} (replaced by {@link #MATCH_PARENT} in
* API Level 8), or a fixed size in pixels
* @param height the height, either {@link #WRAP_CONTENT},
* {@link #FILL_PARENT} (replaced by {@link #MATCH_PARENT} in
* API Level 8), or a fixed size in pixels
*/
public LayoutParams(int width, int height) {
this.width = width;
this.height = height;
}
/**
* Copy constructor. Clones the width and height values of the source.
*
* @param source The layout params to copy from.
*/
public LayoutParams(LayoutParams source) {
this.width = source.width;
this.height = source.height;
}
/**
* Used internally by MarginLayoutParams.
* @hide
*/
LayoutParams() {
}
/**
* Extracts the layout parameters from the supplied attributes.
*
* @param a the style attributes to extract the parameters from
* @param widthAttr the identifier of the width attribute
* @param heightAttr the identifier of the height attribute
*/
protected void setBaseAttributes(TypedArray a, int widthAttr, int heightAttr) {
width = a.getLayoutDimension(widthAttr, "layout_width");
height = a.getLayoutDimension(heightAttr, "layout_height");
}
/**
* Resolve layout parameters depending on the layout direction. Subclasses that care about
* layoutDirection changes should override this method. The default implementation does
* nothing.
*
* @param layoutDirection the direction of the layout
*
* {@link View#LAYOUT_DIRECTION_LTR}
* {@link View#LAYOUT_DIRECTION_RTL}
*/
public void resolveLayoutDirection(int layoutDirection) {
}
/**
* Returns a String representation of this set of layout parameters.
*
* @param output the String to prepend to the internal representation
* @return a String with the following format: output +
* "ViewGroup.LayoutParams={ width=WIDTH, height=HEIGHT }"
*
* @hide
*/
public String debug(String output) {
return output + "ViewGroup.LayoutParams={ width="
+ sizeToString(width) + ", height=" + sizeToString(height) + " }";
}
/**
* Use {@code canvas} to draw suitable debugging annotations for these LayoutParameters.
*
* @param view the view that contains these layout parameters
* @param canvas the canvas on which to draw
*
* @hide
*/
public void onDebugDraw(View view, Canvas canvas, Paint paint) {
}
/**
* Converts the specified size to a readable String.
*
* @param size the size to convert
* @return a String instance representing the supplied size
*
* @hide
*/
protected static String sizeToString(int size) {
if (size == WRAP_CONTENT) {
return "wrap-content";
}
if (size == MATCH_PARENT) {
return "match-parent";
}
return String.valueOf(size);
}
}
/**
* Per-child layout information for layouts that support margins.
* See
* {@link android.R.styleable#ViewGroup_MarginLayout ViewGroup Margin Layout Attributes}
* for a list of all child view attributes that this class supports.
*/
public static class MarginLayoutParams extends ViewGroup.LayoutParams {
/**
* The left margin in pixels of the child.
* Call {@link ViewGroup#setLayoutParams(LayoutParams)} after reassigning a new value
* to this field.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int leftMargin;
/**
* The top margin in pixels of the child.
* Call {@link ViewGroup#setLayoutParams(LayoutParams)} after reassigning a new value
* to this field.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int topMargin;
/**
* The right margin in pixels of the child.
* Call {@link ViewGroup#setLayoutParams(LayoutParams)} after reassigning a new value
* to this field.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int rightMargin;
/**
* The bottom margin in pixels of the child.
* Call {@link ViewGroup#setLayoutParams(LayoutParams)} after reassigning a new value
* to this field.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int bottomMargin;
/**
* The start margin in pixels of the child.
* Call {@link ViewGroup#setLayoutParams(LayoutParams)} after reassigning a new value
* to this field.
*/
@ViewDebug.ExportedProperty(category = "layout")
private int startMargin = DEFAULT_MARGIN_RELATIVE;
/**
* The end margin in pixels of the child.
* Call {@link ViewGroup#setLayoutParams(LayoutParams)} after reassigning a new value
* to this field.
*/
@ViewDebug.ExportedProperty(category = "layout")
private int endMargin = DEFAULT_MARGIN_RELATIVE;
/**
* The default start and end margin.
* @hide
*/
public static final int DEFAULT_MARGIN_RELATIVE = Integer.MIN_VALUE;
/**
* Bit 0: layout direction
* Bit 1: layout direction
* Bit 2: left margin undefined
* Bit 3: right margin undefined
* Bit 4: is RTL compatibility mode
* Bit 5: need resolution
*
* Bit 6 to 7 not used
*
* @hide
*/
@ViewDebug.ExportedProperty(category = "layout", flagMapping = {
@ViewDebug.FlagToString(mask = LAYOUT_DIRECTION_MASK,
equals = LAYOUT_DIRECTION_MASK, name = "LAYOUT_DIRECTION"),
@ViewDebug.FlagToString(mask = LEFT_MARGIN_UNDEFINED_MASK,
equals = LEFT_MARGIN_UNDEFINED_MASK, name = "LEFT_MARGIN_UNDEFINED_MASK"),
@ViewDebug.FlagToString(mask = RIGHT_MARGIN_UNDEFINED_MASK,
equals = RIGHT_MARGIN_UNDEFINED_MASK, name = "RIGHT_MARGIN_UNDEFINED_MASK"),
@ViewDebug.FlagToString(mask = RTL_COMPATIBILITY_MODE_MASK,
equals = RTL_COMPATIBILITY_MODE_MASK, name = "RTL_COMPATIBILITY_MODE_MASK"),
@ViewDebug.FlagToString(mask = NEED_RESOLUTION_MASK,
equals = NEED_RESOLUTION_MASK, name = "NEED_RESOLUTION_MASK")
})
byte mMarginFlags;
private static final int LAYOUT_DIRECTION_MASK = 0x00000003;
private static final int LEFT_MARGIN_UNDEFINED_MASK = 0x00000004;
private static final int RIGHT_MARGIN_UNDEFINED_MASK = 0x00000008;
private static final int RTL_COMPATIBILITY_MODE_MASK = 0x00000010;
private static final int NEED_RESOLUTION_MASK = 0x00000020;
private static final int DEFAULT_MARGIN_RESOLVED = 0;
private static final int UNDEFINED_MARGIN = DEFAULT_MARGIN_RELATIVE;
/**
* Creates a new set of layout parameters. The values are extracted from
* the supplied attributes set and context.
*
* @param c the application environment
* @param attrs the set of attributes from which to extract the layout
* parameters' values
*/
public MarginLayoutParams(Context c, AttributeSet attrs) {
super();
TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.ViewGroup_MarginLayout);
setBaseAttributes(a,
R.styleable.ViewGroup_MarginLayout_layout_width,
R.styleable.ViewGroup_MarginLayout_layout_height);
int margin = a.getDimensionPixelSize(
com.android.internal.R.styleable.ViewGroup_MarginLayout_layout_margin, -1);
if (margin >= 0) {
leftMargin = margin;
topMargin = margin;
rightMargin= margin;
bottomMargin = margin;
} else {
leftMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginLeft,
UNDEFINED_MARGIN);
if (leftMargin == UNDEFINED_MARGIN) {
mMarginFlags |= LEFT_MARGIN_UNDEFINED_MASK;
leftMargin = DEFAULT_MARGIN_RESOLVED;
}
rightMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginRight,
UNDEFINED_MARGIN);
if (rightMargin == UNDEFINED_MARGIN) {
mMarginFlags |= RIGHT_MARGIN_UNDEFINED_MASK;
rightMargin = DEFAULT_MARGIN_RESOLVED;
}
topMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginTop,
DEFAULT_MARGIN_RESOLVED);
bottomMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginBottom,
DEFAULT_MARGIN_RESOLVED);
startMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginStart,
DEFAULT_MARGIN_RELATIVE);
endMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginEnd,
DEFAULT_MARGIN_RELATIVE);
if (isMarginRelative()) {
mMarginFlags |= NEED_RESOLUTION_MASK;
}
}
final boolean hasRtlSupport = c.getApplicationInfo().hasRtlSupport();
final int targetSdkVersion = c.getApplicationInfo().targetSdkVersion;
if (targetSdkVersion < JELLY_BEAN_MR1 || !hasRtlSupport) {
mMarginFlags |= RTL_COMPATIBILITY_MODE_MASK;
}
// Layout direction is LTR by default
mMarginFlags |= LAYOUT_DIRECTION_LTR;
a.recycle();
}
/**
* {@inheritDoc}
*/
public MarginLayoutParams(int width, int height) {
super(width, height);
mMarginFlags |= LEFT_MARGIN_UNDEFINED_MASK;
mMarginFlags |= RIGHT_MARGIN_UNDEFINED_MASK;
mMarginFlags &= ~NEED_RESOLUTION_MASK;
mMarginFlags &= ~RTL_COMPATIBILITY_MODE_MASK;
}
/**
* Copy constructor. Clones the width, height and margin values of the source.
*
* @param source The layout params to copy from.
*/
public MarginLayoutParams(MarginLayoutParams source) {
this.width = source.width;
this.height = source.height;
this.leftMargin = source.leftMargin;
this.topMargin = source.topMargin;
this.rightMargin = source.rightMargin;
this.bottomMargin = source.bottomMargin;
this.startMargin = source.startMargin;
this.endMargin = source.endMargin;
this.mMarginFlags = source.mMarginFlags;
}
/**
* {@inheritDoc}
*/
public MarginLayoutParams(LayoutParams source) {
super(source);
mMarginFlags |= LEFT_MARGIN_UNDEFINED_MASK;
mMarginFlags |= RIGHT_MARGIN_UNDEFINED_MASK;
mMarginFlags &= ~NEED_RESOLUTION_MASK;
mMarginFlags &= ~RTL_COMPATIBILITY_MODE_MASK;
}
/**
* Sets the margins, in pixels. A call to {@link android.view.View#requestLayout()} needs
* to be done so that the new margins are taken into account. Left and right margins may be
* overriden by {@link android.view.View#requestLayout()} depending on layout direction.
*
* @param left the left margin size
* @param top the top margin size
* @param right the right margin size
* @param bottom the bottom margin size
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginLeft
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginTop
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginRight
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginBottom
*/
public void setMargins(int left, int top, int right, int bottom) {
leftMargin = left;
topMargin = top;
rightMargin = right;
bottomMargin = bottom;
mMarginFlags &= ~LEFT_MARGIN_UNDEFINED_MASK;
mMarginFlags &= ~RIGHT_MARGIN_UNDEFINED_MASK;
if (isMarginRelative()) {
mMarginFlags |= NEED_RESOLUTION_MASK;
} else {
mMarginFlags &= ~NEED_RESOLUTION_MASK;
}
}
/**
* Sets the relative margins, in pixels. A call to {@link android.view.View#requestLayout()}
* needs to be done so that the new relative margins are taken into account. Left and right
* margins may be overriden by {@link android.view.View#requestLayout()} depending on layout
* direction.
*
* @param start the start margin size
* @param top the top margin size
* @param end the right margin size
* @param bottom the bottom margin size
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginStart
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginTop
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginEnd
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginBottom
*
* @hide
*/
public void setMarginsRelative(int start, int top, int end, int bottom) {
startMargin = start;
topMargin = top;
endMargin = end;
bottomMargin = bottom;
mMarginFlags |= NEED_RESOLUTION_MASK;
}
/**
* Sets the relative start margin.
*
* @param start the start margin size
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginStart
*/
public void setMarginStart(int start) {
startMargin = start;
mMarginFlags |= NEED_RESOLUTION_MASK;
}
/**
* Returns the start margin in pixels.
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginStart
*
* @return the start margin in pixels.
*/
public int getMarginStart() {
if (startMargin != DEFAULT_MARGIN_RELATIVE) return startMargin;
if ((mMarginFlags & NEED_RESOLUTION_MASK) == NEED_RESOLUTION_MASK) {
doResolveMargins();
}
switch(mMarginFlags & LAYOUT_DIRECTION_MASK) {
case View.LAYOUT_DIRECTION_RTL:
return rightMargin;
case View.LAYOUT_DIRECTION_LTR:
default:
return leftMargin;
}
}
/**
* Sets the relative end margin.
*
* @param end the end margin size
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginEnd
*/
public void setMarginEnd(int end) {
endMargin = end;
mMarginFlags |= NEED_RESOLUTION_MASK;
}
/**
* Returns the end margin in pixels.
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginEnd
*
* @return the end margin in pixels.
*/
public int getMarginEnd() {
if (endMargin != DEFAULT_MARGIN_RELATIVE) return endMargin;
if ((mMarginFlags & NEED_RESOLUTION_MASK) == NEED_RESOLUTION_MASK) {
doResolveMargins();
}
switch(mMarginFlags & LAYOUT_DIRECTION_MASK) {
case View.LAYOUT_DIRECTION_RTL:
return leftMargin;
case View.LAYOUT_DIRECTION_LTR:
default:
return rightMargin;
}
}
/**
* Check if margins are relative.
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginStart
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginEnd
*
* @return true if either marginStart or marginEnd has been set.
*/
public boolean isMarginRelative() {
return (startMargin != DEFAULT_MARGIN_RELATIVE || endMargin != DEFAULT_MARGIN_RELATIVE);
}
/**
* Set the layout direction
* @param layoutDirection the layout direction.
* Should be either {@link View#LAYOUT_DIRECTION_LTR}
* or {@link View#LAYOUT_DIRECTION_RTL}.
*/
public void setLayoutDirection(int layoutDirection) {
if (layoutDirection != View.LAYOUT_DIRECTION_LTR &&
layoutDirection != View.LAYOUT_DIRECTION_RTL) return;
if (layoutDirection != (mMarginFlags & LAYOUT_DIRECTION_MASK)) {
mMarginFlags &= ~LAYOUT_DIRECTION_MASK;
mMarginFlags |= (layoutDirection & LAYOUT_DIRECTION_MASK);
if (isMarginRelative()) {
mMarginFlags |= NEED_RESOLUTION_MASK;
} else {
mMarginFlags &= ~NEED_RESOLUTION_MASK;
}
}
}
/**
* Retuns the layout direction. Can be either {@link View#LAYOUT_DIRECTION_LTR} or
* {@link View#LAYOUT_DIRECTION_RTL}.
*
* @return the layout direction.
*/
public int getLayoutDirection() {
return (mMarginFlags & LAYOUT_DIRECTION_MASK);
}
/**
* This will be called by {@link android.view.View#requestLayout()}. Left and Right margins
* may be overridden depending on layout direction.
*/
@Override
public void resolveLayoutDirection(int layoutDirection) {
setLayoutDirection(layoutDirection);
// No relative margin or pre JB-MR1 case or no need to resolve, just dont do anything
// Will use the left and right margins if no relative margin is defined.
if (!isMarginRelative() ||
(mMarginFlags & NEED_RESOLUTION_MASK) != NEED_RESOLUTION_MASK) return;
// Proceed with resolution
doResolveMargins();
}
private void doResolveMargins() {
if ((mMarginFlags & RTL_COMPATIBILITY_MODE_MASK) == RTL_COMPATIBILITY_MODE_MASK) {
// if left or right margins are not defined and if we have some start or end margin
// defined then use those start and end margins.
if ((mMarginFlags & LEFT_MARGIN_UNDEFINED_MASK) == LEFT_MARGIN_UNDEFINED_MASK
&& startMargin > DEFAULT_MARGIN_RELATIVE) {
leftMargin = startMargin;
}
if ((mMarginFlags & RIGHT_MARGIN_UNDEFINED_MASK) == RIGHT_MARGIN_UNDEFINED_MASK
&& endMargin > DEFAULT_MARGIN_RELATIVE) {
rightMargin = endMargin;
}
} else {
// We have some relative margins (either the start one or the end one or both). So use
// them and override what has been defined for left and right margins. If either start
// or end margin is not defined, just set it to default "0".
switch(mMarginFlags & LAYOUT_DIRECTION_MASK) {
case View.LAYOUT_DIRECTION_RTL:
leftMargin = (endMargin > DEFAULT_MARGIN_RELATIVE) ?
endMargin : DEFAULT_MARGIN_RESOLVED;
rightMargin = (startMargin > DEFAULT_MARGIN_RELATIVE) ?
startMargin : DEFAULT_MARGIN_RESOLVED;
break;
case View.LAYOUT_DIRECTION_LTR:
default:
leftMargin = (startMargin > DEFAULT_MARGIN_RELATIVE) ?
startMargin : DEFAULT_MARGIN_RESOLVED;
rightMargin = (endMargin > DEFAULT_MARGIN_RELATIVE) ?
endMargin : DEFAULT_MARGIN_RESOLVED;
break;
}
}
mMarginFlags &= ~NEED_RESOLUTION_MASK;
}
/**
* @hide
*/
public boolean isLayoutRtl() {
return ((mMarginFlags & LAYOUT_DIRECTION_MASK) == View.LAYOUT_DIRECTION_RTL);
}
/**
* @hide
*/
@Override
public void onDebugDraw(View view, Canvas canvas, Paint paint) {
Insets oi = isLayoutModeOptical(view.mParent) ? view.getOpticalInsets() : Insets.NONE;
fillDifference(canvas,
view.getLeft() + oi.left,
view.getTop() + oi.top,
view.getRight() - oi.right,
view.getBottom() - oi.bottom,
leftMargin,
topMargin,
rightMargin,
bottomMargin,
paint);
}
}
/* Describes a touched view and the ids of the pointers that it has captured.
*
* This code assumes that pointer ids are always in the range 0..31 such that
* it can use a bitfield to track which pointer ids are present.
* As it happens, the lower layers of the input dispatch pipeline also use the
* same trick so the assumption should be safe here...
*/
private static final class TouchTarget {
private static final int MAX_RECYCLED = 32;
private static final Object sRecycleLock = new Object[0];
private static TouchTarget sRecycleBin;
private static int sRecycledCount;
public static final int ALL_POINTER_IDS = -1; // all ones
// The touched child view.
public View child;
// The combined bit mask of pointer ids for all pointers captured by the target.
public int pointerIdBits;
// The next target in the target list.
public TouchTarget next;
private TouchTarget() {
}
public static TouchTarget obtain(View child, int pointerIdBits) {
final TouchTarget target;
synchronized (sRecycleLock) {
if (sRecycleBin == null) {
target = new TouchTarget();
} else {
target = sRecycleBin;
sRecycleBin = target.next;
sRecycledCount--;
target.next = null;
}
}
target.child = child;
target.pointerIdBits = pointerIdBits;
return target;
}
public void recycle() {
synchronized (sRecycleLock) {
if (sRecycledCount < MAX_RECYCLED) {
next = sRecycleBin;
sRecycleBin = this;
sRecycledCount += 1;
} else {
next = null;
}
child = null;
}
}
}
/* Describes a hovered view. */
private static final class HoverTarget {
private static final int MAX_RECYCLED = 32;
private static final Object sRecycleLock = new Object[0];
private static HoverTarget sRecycleBin;
private static int sRecycledCount;
// The hovered child view.
public View child;
// The next target in the target list.
public HoverTarget next;
private HoverTarget() {
}
public static HoverTarget obtain(View child) {
final HoverTarget target;
synchronized (sRecycleLock) {
if (sRecycleBin == null) {
target = new HoverTarget();
} else {
target = sRecycleBin;
sRecycleBin = target.next;
sRecycledCount--;
target.next = null;
}
}
target.child = child;
return target;
}
public void recycle() {
synchronized (sRecycleLock) {
if (sRecycledCount < MAX_RECYCLED) {
next = sRecycleBin;
sRecycleBin = this;
sRecycledCount += 1;
} else {
next = null;
}
child = null;
}
}
}
/**
* Pooled class that orderes the children of a ViewGroup from start
* to end based on how they are laid out and the layout direction.
*/
static class ChildListForAccessibility {
private static final int MAX_POOL_SIZE = 32;
private static final SynchronizedPool sPool =
new SynchronizedPool(MAX_POOL_SIZE);
private final ArrayList mChildren = new ArrayList();
private final ArrayList mHolders = new ArrayList();
public static ChildListForAccessibility obtain(ViewGroup parent, boolean sort) {
ChildListForAccessibility list = sPool.acquire();
if (list == null) {
list = new ChildListForAccessibility();
}
list.init(parent, sort);
return list;
}
public void recycle() {
clear();
sPool.release(this);
}
public int getChildCount() {
return mChildren.size();
}
public View getChildAt(int index) {
return mChildren.get(index);
}
public int getChildIndex(View child) {
return mChildren.indexOf(child);
}
private void init(ViewGroup parent, boolean sort) {
ArrayList children = mChildren;
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
children.add(child);
}
if (sort) {
ArrayList holders = mHolders;
for (int i = 0; i < childCount; i++) {
View child = children.get(i);
ViewLocationHolder holder = ViewLocationHolder.obtain(parent, child);
holders.add(holder);
}
Collections.sort(holders);
for (int i = 0; i < childCount; i++) {
ViewLocationHolder holder = holders.get(i);
children.set(i, holder.mView);
holder.recycle();
}
holders.clear();
}
}
private void clear() {
mChildren.clear();
}
}
/**
* Pooled class that holds a View and its location with respect to
* a specified root. This enables sorting of views based on their
* coordinates without recomputing the position relative to the root
* on every comparison.
*/
static class ViewLocationHolder implements Comparable {
private static final int MAX_POOL_SIZE = 32;
private static final SynchronizedPool sPool =
new SynchronizedPool(MAX_POOL_SIZE);
private final Rect mLocation = new Rect();
public View mView;
private int mLayoutDirection;
public static ViewLocationHolder obtain(ViewGroup root, View view) {
ViewLocationHolder holder = sPool.acquire();
if (holder == null) {
holder = new ViewLocationHolder();
}
holder.init(root, view);
return holder;
}
public void recycle() {
clear();
sPool.release(this);
}
@Override
public int compareTo(ViewLocationHolder another) {
// This instance is greater than an invalid argument.
if (another == null) {
return 1;
}
if (getClass() != another.getClass()) {
return 1;
}
// First is above second.
if (mLocation.bottom - another.mLocation.top <= 0) {
return -1;
}
// First is below second.
if (mLocation.top - another.mLocation.bottom >= 0) {
return 1;
}
// LTR
if (mLayoutDirection == LAYOUT_DIRECTION_LTR) {
final int leftDifference = mLocation.left - another.mLocation.left;
// First more to the left than second.
if (leftDifference != 0) {
return leftDifference;
}
} else { // RTL
final int rightDifference = mLocation.right - another.mLocation.right;
// First more to the right than second.
if (rightDifference != 0) {
return -rightDifference;
}
}
// Break tie by top.
final int topDiference = mLocation.top - another.mLocation.top;
if (topDiference != 0) {
return topDiference;
}
// Break tie by height.
final int heightDiference = mLocation.height() - another.mLocation.height();
if (heightDiference != 0) {
return -heightDiference;
}
// Break tie by width.
final int widthDiference = mLocation.width() - another.mLocation.width();
if (widthDiference != 0) {
return -widthDiference;
}
// Just break the tie somehow. The accessibliity ids are unique
// and stable, hence this is deterministic tie breaking.
return mView.getAccessibilityViewId() - another.mView.getAccessibilityViewId();
}
private void init(ViewGroup root, View view) {
Rect viewLocation = mLocation;
view.getDrawingRect(viewLocation);
root.offsetDescendantRectToMyCoords(view, viewLocation);
mView = view;
mLayoutDirection = root.getLayoutDirection();
}
private void clear() {
mView = null;
mLocation.set(0, 0, 0, 0);
}
}
private static Paint getDebugPaint() {
if (sDebugPaint == null) {
sDebugPaint = new Paint();
sDebugPaint.setAntiAlias(false);
}
return sDebugPaint;
}
private static void drawRect(Canvas canvas, Paint paint, int x1, int y1, int x2, int y2) {
if (sDebugLines== null) {
// TODO: This won't work with multiple UI threads in a single process
sDebugLines = new float[16];
}
sDebugLines[0] = x1;
sDebugLines[1] = y1;
sDebugLines[2] = x2;
sDebugLines[3] = y1;
sDebugLines[4] = x2;
sDebugLines[5] = y1;
sDebugLines[6] = x2;
sDebugLines[7] = y2;
sDebugLines[8] = x2;
sDebugLines[9] = y2;
sDebugLines[10] = x1;
sDebugLines[11] = y2;
sDebugLines[12] = x1;
sDebugLines[13] = y2;
sDebugLines[14] = x1;
sDebugLines[15] = y1;
canvas.drawLines(sDebugLines, paint);
}
}
语言表达能力一般，请见谅。
View.java:
/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.view;
import android.content.ClipData;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Insets;
import android.graphics.Interpolator;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Point;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Region;
import android.graphics.Shader;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.hardware.display.DisplayManagerGlobal;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Parcel;
import android.os.Parcelable;
import android.os.RemoteException;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.FloatProperty;
import android.util.LayoutDirection;
import android.util.Log;
import android.util.LongSparseLongArray;
import android.util.Pools.SynchronizedPool;
import android.util.Property;
import android.util.SparseArray;
import android.util.SuperNotCalledException;
import android.util.TypedValue;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.AccessibilityIterators.TextSegmentIterator;
import android.view.AccessibilityIterators.CharacterTextSegmentIterator;
import android.view.AccessibilityIterators.WordTextSegmentIterator;
import android.view.AccessibilityIterators.ParagraphTextSegmentIterator;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityEventSource;
import android.view.accessibility.AccessibilityManager;
import android.view.accessibility.AccessibilityNodeInfo;
import android.view.accessibility.AccessibilityNodeProvider;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.Transformation;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.view.inputmethod.InputMethodManager;
import android.widget.ScrollBarDrawable;
import static android.os.Build.VERSION_CODES.*;
import static java.lang.Math.max;
import com.android.internal.R;
import com.android.internal.util.Predicate;
import com.android.internal.view.menu.MenuBuilder;
import com.google.android.collect.Lists;
import com.google.android.collect.Maps;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Locale;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicInteger;
/**
*
* This class represents the basic building block for user interface components. A View
* occupies a rectangular area on the screen and is responsible for drawing and
* event handling. View is the base class for widgets, which are
* used to create interactive UI components (buttons, text fields, etc.). The
* {@link android.view.ViewGroup} subclass is the base class for layouts, which
* are invisible containers that hold other Views (or other ViewGroups) and define
* their layout properties.
*
*
*
*
Developer Guides
*
For information about using this class to develop your application's user interface,
* read the User Interface developer guide.
*
*
*
*
Using Views
*
* All of the views in a window are arranged in a single tree. You can add views
* either from code or by specifying a tree of views in one or more XML layout
* files. There are many specialized subclasses of views that act as controls or
* are capable of displaying text, images, or other content.
*
*
* Once you have created a tree of views, there are typically a few types of
* common operations you may wish to perform:
*
*
Set properties: for example setting the text of a
* {@link android.widget.TextView}. The available properties and the methods
* that set them will vary among the different subclasses of views. Note that
* properties that are known at build time can be set in the XML layout
* files.
*
Set focus: The framework will handled moving focus in
* response to user input. To force focus to a specific view, call
* {@link #requestFocus}.
*
Set up listeners: Views allow clients to set listeners
* that will be notified when something interesting happens to the view. For
* example, all views will let you set a listener to be notified when the view
* gains or loses focus. You can register such a listener using
* {@link #setOnFocusChangeListener(android.view.View.OnFocusChangeListener)}.
* Other view subclasses offer more specialized listeners. For example, a Button
* exposes a listener to notify clients when the button is clicked.
*
Set visibility: You can hide or show views using
* {@link #setVisibility(int)}.
*
*
*
* Note: The Android framework is responsible for measuring, laying out and
* drawing views. You should not call methods that perform these actions on
* views yourself unless you are actually implementing a
* {@link android.view.ViewGroup}.
*
*
*
*
Implementing a Custom View
*
*
* To implement a custom view, you will usually begin by providing overrides for
* some of the standard methods that the framework calls on all views. You do
* not need to override all of these methods. In fact, you can start by just
* overriding {@link #onDraw(android.graphics.Canvas)}.
*
*
*
Category
Methods
Description
*
*
*
*
*
Creation
*
Constructors
*
There is a form of the constructor that are called when the view
* is created from code and a form that is called when the view is
* inflated from a layout file. The second form should parse and apply
* any attributes defined in the layout file.
*
*
*
*
{@link #onFinishInflate()}
*
Called after a view and all of its children has been inflated
* from XML.
*
*
*
*
Layout
*
{@link #onMeasure(int, int)}
*
Called to determine the size requirements for this view and all
* of its children.
*
*
*
*
{@link #onLayout(boolean, int, int, int, int)}
*
Called when this view should assign a size and position to all
* of its children.
*
Called when the window containing the view gains or loses focus.
*
*
*
*
*
Attaching
*
{@link #onAttachedToWindow()}
*
Called when the view is attached to a window.
*
*
*
*
*
{@link #onDetachedFromWindow}
*
Called when the view is detached from its window.
*
*
*
*
*
{@link #onWindowVisibilityChanged(int)}
*
Called when the visibility of the window containing the view
* has changed.
*
*
*
*
*
*
*
*
*
IDs
* Views may have an integer id associated with them. These ids are typically
* assigned in the layout XML files, and are used to find specific views within
* the view tree. A common pattern is to:
*
*
Define a Button in the layout file and assign it a unique ID.
*
*
*
*
From the onCreate method of an Activity, find the Button
*
* View IDs need not be unique throughout the tree, but it is good practice to
* ensure that they are at least unique within the part of the tree you are
* searching.
*
*
*
*
Position
*
* The geometry of a view is that of a rectangle. A view has a location,
* expressed as a pair of left and top coordinates, and
* two dimensions, expressed as a width and a height. The unit for location
* and dimensions is the pixel.
*
*
*
* It is possible to retrieve the location of a view by invoking the methods
* {@link #getLeft()} and {@link #getTop()}. The former returns the left, or X,
* coordinate of the rectangle representing the view. The latter returns the
* top, or Y, coordinate of the rectangle representing the view. These methods
* both return the location of the view relative to its parent. For instance,
* when getLeft() returns 20, that means the view is located 20 pixels to the
* right of the left edge of its direct parent.
*
*
*
* In addition, several convenience methods are offered to avoid unnecessary
* computations, namely {@link #getRight()} and {@link #getBottom()}.
* These methods return the coordinates of the right and bottom edges of the
* rectangle representing the view. For instance, calling {@link #getRight()}
* is similar to the following computation: getLeft() + getWidth()
* (see Size for more information about the width.)
*
*
*
*
Size, padding and margins
*
* The size of a view is expressed with a width and a height. A view actually
* possess two pairs of width and height values.
*
*
*
* The first pair is known as measured width and
* measured height. These dimensions define how big a view wants to be
* within its parent (see Layout for more details.) The
* measured dimensions can be obtained by calling {@link #getMeasuredWidth()}
* and {@link #getMeasuredHeight()}.
*
*
*
* The second pair is simply known as width and height, or
* sometimes drawing width and drawing height. These
* dimensions define the actual size of the view on screen, at drawing time and
* after layout. These values may, but do not have to, be different from the
* measured width and height. The width and height can be obtained by calling
* {@link #getWidth()} and {@link #getHeight()}.
*
*
*
* To measure its dimensions, a view takes into account its padding. The padding
* is expressed in pixels for the left, top, right and bottom parts of the view.
* Padding can be used to offset the content of the view by a specific amount of
* pixels. For instance, a left padding of 2 will push the view's content by
* 2 pixels to the right of the left edge. Padding can be set using the
* {@link #setPadding(int, int, int, int)} or {@link #setPaddingRelative(int, int, int, int)}
* method and queried by calling {@link #getPaddingLeft()}, {@link #getPaddingTop()},
* {@link #getPaddingRight()}, {@link #getPaddingBottom()}, {@link #getPaddingStart()},
* {@link #getPaddingEnd()}.
*
*
*
* Even though a view can define a padding, it does not provide any support for
* margins. However, view groups provide such a support. Refer to
* {@link android.view.ViewGroup} and
* {@link android.view.ViewGroup.MarginLayoutParams} for further information.
*
*
*
*
Layout
*
* Layout is a two pass process: a measure pass and a layout pass. The measuring
* pass is implemented in {@link #measure(int, int)} and is a top-down traversal
* of the view tree. Each view pushes dimension specifications down the tree
* during the recursion. At the end of the measure pass, every view has stored
* its measurements. The second pass happens in
* {@link #layout(int,int,int,int)} and is also top-down. During
* this pass each parent is responsible for positioning all of its children
* using the sizes computed in the measure pass.
*
*
*
* When a view's measure() method returns, its {@link #getMeasuredWidth()} and
* {@link #getMeasuredHeight()} values must be set, along with those for all of
* that view's descendants. A view's measured width and measured height values
* must respect the constraints imposed by the view's parents. This guarantees
* that at the end of the measure pass, all parents accept all of their
* children's measurements. A parent view may call measure() more than once on
* its children. For example, the parent may measure each child once with
* unspecified dimensions to find out how big they want to be, then call
* measure() on them again with actual numbers if the sum of all the children's
* unconstrained sizes is too big or too small.
*
*
*
* The measure pass uses two classes to communicate dimensions. The
* {@link MeasureSpec} class is used by views to tell their parents how they
* want to be measured and positioned. The base LayoutParams class just
* describes how big the view wants to be for both width and height. For each
* dimension, it can specify one of:
*
*
an exact number
*
MATCH_PARENT, which means the view wants to be as big as its parent
* (minus padding)
*
WRAP_CONTENT, which means that the view wants to be just big enough to
* enclose its content (plus padding).
*
* There are subclasses of LayoutParams for different subclasses of ViewGroup.
* For example, AbsoluteLayout has its own subclass of LayoutParams which adds
* an X and Y value.
*
*
*
* MeasureSpecs are used to push requirements down the tree from parent to
* child. A MeasureSpec can be in one of three modes:
*
*
UNSPECIFIED: This is used by a parent to determine the desired dimension
* of a child view. For example, a LinearLayout may call measure() on its child
* with the height set to UNSPECIFIED and a width of EXACTLY 240 to find out how
* tall the child view wants to be given a width of 240 pixels.
*
EXACTLY: This is used by the parent to impose an exact size on the
* child. The child must use this size, and guarantee that all of its
* descendants will fit within this size.
*
AT_MOST: This is used by the parent to impose a maximum size on the
* child. The child must gurantee that it and all of its descendants will fit
* within this size.
*
*
*
*
* To intiate a layout, call {@link #requestLayout}. This method is typically
* called by a view on itself when it believes that is can no longer fit within
* its current bounds.
*
*
*
*
Drawing
*
* Drawing is handled by walking the tree and rendering each view that
* intersects the invalid region. Because the tree is traversed in-order,
* this means that parents will draw before (i.e., behind) their children, with
* siblings drawn in the order they appear in the tree.
* If you set a background drawable for a View, then the View will draw it for you
* before calling back to its onDraw() method.
*
*
*
* Note that the framework will not draw views that are not in the invalid region.
*
*
*
* To force a view to draw, call {@link #invalidate()}.
*
*
*
*
Event Handling and Threading
*
* The basic cycle of a view is as follows:
*
*
An event comes in and is dispatched to the appropriate view. The view
* handles the event and notifies any listeners.
*
If in the course of processing the event, the view's bounds may need
* to be changed, the view will call {@link #requestLayout()}.
*
Similarly, if in the course of processing the event the view's appearance
* may need to be changed, the view will call {@link #invalidate()}.
*
If either {@link #requestLayout()} or {@link #invalidate()} were called,
* the framework will take care of measuring, laying out, and drawing the tree
* as appropriate.
*
*
*
*
Note: The entire view tree is single threaded. You must always be on
* the UI thread when calling any method on any view.
* If you are doing work on other threads and want to update the state of a view
* from that thread, you should use a {@link Handler}.
*
*
*
*
Focus Handling
*
* The framework will handle routine focus movement in response to user input.
* This includes changing the focus as views are removed or hidden, or as new
* views become available. Views indicate their willingness to take focus
* through the {@link #isFocusable} method. To change whether a view can take
* focus, call {@link #setFocusable(boolean)}. When in touch mode (see notes below)
* views indicate whether they still would like focus via {@link #isFocusableInTouchMode}
* and can change this via {@link #setFocusableInTouchMode(boolean)}.
*
*
* Focus movement is based on an algorithm which finds the nearest neighbor in a
* given direction. In rare cases, the default algorithm may not match the
* intended behavior of the developer. In these situations, you can provide
* explicit overrides by using these XML attributes in the layout file:
*
* To get a particular view to take focus, call {@link #requestFocus()}.
*
*
*
*
Touch Mode
*
* When a user is navigating a user interface via directional keys such as a D-pad, it is
* necessary to give focus to actionable items such as buttons so the user can see
* what will take input. If the device has touch capabilities, however, and the user
* begins interacting with the interface by touching it, it is no longer necessary to
* always highlight, or give focus to, a particular view. This motivates a mode
* for interaction named 'touch mode'.
*
*
* For a touch capable device, once the user touches the screen, the device
* will enter touch mode. From this point onward, only views for which
* {@link #isFocusableInTouchMode} is true will be focusable, such as text editing widgets.
* Other views that are touchable, like buttons, will not take focus when touched; they will
* only fire the on click listeners.
*
*
* Any time a user hits a directional key, such as a D-pad direction, the view device will
* exit touch mode, and find a view to take focus, so that the user may resume interacting
* with the user interface without touching the screen again.
*
*
* The touch mode state is maintained across {@link android.app.Activity}s. Call
* {@link #isInTouchMode} to see whether the device is currently in touch mode.
*
*
*
*
Scrolling
*
* The framework provides basic support for views that wish to internally
* scroll their content. This includes keeping track of the X and Y scroll
* offset as well as mechanisms for drawing scrollbars. See
* {@link #scrollBy(int, int)}, {@link #scrollTo(int, int)}, and
* {@link #awakenScrollBars()} for more details.
*
*
*
*
Tags
*
* Unlike IDs, tags are not used to identify views. Tags are essentially an
* extra piece of information that can be associated with a view. They are most
* often used as a convenience to store data related to views in the views
* themselves rather than by putting them in a separate structure.
*
*
*
*
Properties
*
* The View class exposes an {@link #ALPHA} property, as well as several transform-related
* properties, such as {@link #TRANSLATION_X} and {@link #TRANSLATION_Y}. These properties are
* available both in the {@link Property} form as well as in similarly-named setter/getter
* methods (such as {@link #setAlpha(float)} for {@link #ALPHA}). These properties can
* be used to set persistent state associated with these rendering-related properties on the view.
* The properties and methods can also be used in conjunction with
* {@link android.animation.Animator Animator}-based animations, described more in the
* Animation section.
*
*
*
*
Animation
*
* Starting with Android 3.0, the preferred way of animating views is to use the
* {@link android.animation} package APIs. These {@link android.animation.Animator Animator}-based
* classes change actual properties of the View object, such as {@link #setAlpha(float) alpha} and
* {@link #setTranslationX(float) translationX}. This behavior is contrasted to that of the pre-3.0
* {@link android.view.animation.Animation Animation}-based classes, which instead animate only
* how the view is drawn on the display. In particular, the {@link ViewPropertyAnimator} class
* makes animating these View properties particularly easy and efficient.
*
*
* Alternatively, you can use the pre-3.0 animation classes to animate how Views are rendered.
* You can attach an {@link Animation} object to a view using
* {@link #setAnimation(Animation)} or
* {@link #startAnimation(Animation)}. The animation can alter the scale,
* rotation, translation and alpha of a view over time. If the animation is
* attached to a view that has children, the animation will affect the entire
* subtree rooted by that node. When an animation is started, the framework will
* take care of redrawing the appropriate views until the animation completes.
*
*
*
*
Security
*
* Sometimes it is essential that an application be able to verify that an action
* is being performed with the full knowledge and consent of the user, such as
* granting a permission request, making a purchase or clicking on an advertisement.
* Unfortunately, a malicious application could try to spoof the user into
* performing these actions, unaware, by concealing the intended purpose of the view.
* As a remedy, the framework offers a touch filtering mechanism that can be used to
* improve the security of views that provide access to sensitive functionality.
*
* To enable touch filtering, call {@link #setFilterTouchesWhenObscured(boolean)} or set the
* android:filterTouchesWhenObscured layout attribute to true. When enabled, the framework
* will discard touches that are received whenever the view's window is obscured by
* another visible window. As a result, the view will not receive touches whenever a
* toast, dialog or other window appears above the view's window.
*
* For more fine-grained control over security, consider overriding the
* {@link #onFilterTouchEventForSecurity(MotionEvent)} method to implement your own
* security policy. See also {@link MotionEvent#FLAG_WINDOW_IS_OBSCURED}.
*
1、网络上现成的资料
格式: sed -i "s/查找字段/替换字段/g" `grep 查找字段 -rl 路径`
linux sed 批量替换多个文件中的字符串
sed -i "s/oldstring/newstring/g" `grep oldstring -rl yourdir`
例如：替换/home下所有文件中的www.admi
对于AJAX应用（使用XMLHttpRequests）来说，向服务器发起请求的传统方式是：获取一个XMLHttpRequest对象的引用、发起请求、读取响应、检查状态码，最后处理服务端的响应。整个过程示例如下：
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange
Hive中的排序语法 2014.06.22 ORDER BY
hive中的ORDER BY语句和关系数据库中的sql语法相似。他会对查询结果做全局排序，这意味着所有的数据会传送到一个Reduce任务上，这样会导致在大数量的情况下，花费大量时间。
与数据库中 ORDER BY 的区别在于在hive.mapred.mode = strict模式下，必须指定 limit 否则执行会报错。
post-commit hook failed (exit code 1) with output:
svn: E155004: Working copy 'D:\xx\xxx' locked
svn: E200031: sqlite: attempt to write a readonly database
svn: E200031: sqlite: attempt to write a
