1.keyEvent 分发过程
WindowManagerGlobal.addView()（添加一个view）
root = new ViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
// do this last because it fires off messages to start doing things
try {
root.setView(view, wparams, panelParentView);
} catch (RuntimeException e) {
// BadTokenException or InvalidDisplayException, clean up.
if (index >= 0) {
removeViewLocked(index, true);
}
throw e;
}
}
此处应该是每添加一个view，就会有一个ViewRootImpl
ViewRootImpl.setView()
/**
* We have one child
*/
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
synchronized (this) {
if (mView == null) {
mView = view;
requestLayout();//最终会调用performTraversals,进而执行 performMeasure/performLaout 等方法
.....
try {
mOrigWindowType = mWindowAttributes.type;
mAttachInfo.mRecomputeGlobalAttributes = true;
collectViewAttributes();
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
getHostVisibility(), mDisplay.getDisplayId(), mWinFrame,
mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
mAttachInfo.mOutsets, mAttachInfo.mDisplayCutout, mInputChannel);
} catch (RemoteException e) {
mAdded = false;
mView = null;
mAttachInfo.mRootView = null;
mInputChannel = null;
mFallbackEventHandler.setView(null);
unscheduleTraversals();
setAccessibilityFocus(null, null);
throw new RuntimeException("Adding window failed", e);
} finally {
if (restore) {
attrs.restore();
}
}
//
CharSequence counterSuffix = attrs.getTitle();
mSyntheticInputStage = new SyntheticInputStage();
InputStage viewPostImeStage = new ViewPostImeInputStage(mSyntheticInputStage);//ViewPostImeInputStage KeyEvent 真正处理
InputStage nativePostImeStage = new NativePostImeInputStage(viewPostImeStage,
"aq:native-post-ime:" + counterSuffix);
InputStage earlyPostImeStage = new EarlyPostImeInputStage(nativePostImeStage);
InputStage imeStage = new ImeInputStage(earlyPostImeStage,
"aq:ime:" + counterSuffix);
InputStage viewPreImeStage = new ViewPreImeInputStage(imeStage);
InputStage nativePreImeStage = new NativePreImeInputStage(viewPreImeStage,
"aq:native-pre-ime:" + counterSuffix);
mFirstInputStage = nativePreImeStage;
mFirstPostImeInputStage = earlyPostImeStage;
mPendingInputEventQueueLengthCounterName = "aq:pending:" + counterSuffix;
}
}
}
ViewPostImeInputStage.processKeyEvent
{
......
// 将event 分发给view树。当前view是DecorView
if (mView.dispatchKeyEvent(event)) {
return FINISH_HANDLED;
}
if (shouldDropInputEvent(q)) {
return FINISH_NOT_HANDLED;
}
.........
// Handle automatic focus changes.
if (event.getAction() == KeyEvent.ACTION_DOWN) {
if (groupNavigationDirection != 0) {
if (performKeyboardGroupNavigation(groupNavigationDirection)) {
return FINISH_HANDLED;
}
} else {
if (performFocusNavigation(event)) {//焦点寻找的关键点
return FINISH_HANDLED;
}
}
}
return FORWARD;
}
}
// The view contained within this ViewGroup that has or contains focus. (View mFocused)
ViewGroup的dispatchKeyEvent:
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onKeyEvent(event, 1);
}
if ((mPrivateFlags & (PFLAG_FOCUSED | PFLAG_HAS_BOUNDS))
== (PFLAG_FOCUSED | PFLAG_HAS_BOUNDS)) {
if (super.dispatchKeyEvent(event)) {
return true;
}
} else if (mFocused != null && (mFocused.mPrivateFlags & PFLAG_HAS_BOUNDS)
== PFLAG_HAS_BOUNDS) {
if (mFocused.dispatchKeyEvent(event)) {// 递归方式遍历
return true;
}
}
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onUnhandledEvent(event, 1);
}
return false;
}
View keyEvent 分发过程：
image.png
一旦dispatchKeyEvent 被拦截返回true，那么就不会进行findNextFoucs操作了
2. 进入Activity 获取第一个焦点的过程
performTraversals 方法:
if (mFirst) {
// handle first focus request
if (DEBUG_INPUT_RESIZE) Log.v(TAG, "First: mView.hasFocus()="
+ mView.hasFocus());
if (mView != null) {
if (!mView.hasFocus()) {
mView.requestFocus(View.FOCUS_FORWARD);//请求下一个焦点
mFocusedView = mRealFocusedView = mView.findFocus();//递归层层寻找，得到ocusedView
if (DEBUG_INPUT_RESIZE) Log.v(TAG, "First: requested focused view="
+ mFocusedView);
} else {
mRealFocusedView = mView.findFocus();
if (DEBUG_INPUT_RESIZE) Log.v(TAG, "First: existing focused view="
+ mRealFocusedView);
}
}
if ((relayoutResult & WindowManagerGlobal.RELAYOUT_RES_ANIMATING) != 0) {
// The first time we relayout the window, if the system is
// doing window animations, we want to hold of on any future
// draws until the animation is done.
mWindowsAnimating = true;
}
} else if (mWindowsAnimating) {
skipDraw = true;
}
最终调用ViewGroup 的
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)) {//第一个view 获取到焦点 就直接返回true
return true;
}
}
}
return false;
}
当找到了占据焦点的View的时候，又会层层回调：mParent.requestChildFocus(this, this);
ps:RecycleView的requestChildFocus
小结：
image.png
3.Button1 占据了焦点，遥控器按下运行逻辑
keyEvent分发完毕之后，进一步调用performFocusNavigation寻找下一个焦点的位置
private boolean performFocusNavigation(KeyEvent event) {
int direction = 0;
switch (event.getKeyCode()) {
case KeyEvent.KEYCODE_DPAD_LEFT:
if (event.hasNoModifiers()) {
direction = View.FOCUS_LEFT;
}
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
if (event.hasNoModifiers()) {
direction = View.FOCUS_RIGHT;
}
break;
case KeyEvent.KEYCODE_DPAD_UP:
if (event.hasNoModifiers()) {
direction = View.FOCUS_UP;
}
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
if (event.hasNoModifiers()) {
direction = View.FOCUS_DOWN;
}
break;
case KeyEvent.KEYCODE_TAB:
if (event.hasNoModifiers()) {
direction = View.FOCUS_FORWARD;
} else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) {
direction = View.FOCUS_BACKWARD;
}
break;
}
if (direction != 0) {
View focused = mView.findFocus();//寻找到当前占据焦点的View递归调用
if (focused != null) {
View v = focused.focusSearch(direction);//重要的focusSearch
if (v != null && v != focused) {
// do the math the get the interesting rect
// of previous focused into the coord system of
// newly focused view
focused.getFocusedRect(mTempRect);
if (mView instanceof ViewGroup) {
((ViewGroup) mView).offsetDescendantRectToMyCoords(
focused, mTempRect);
((ViewGroup) mView).offsetRectIntoDescendantCoords(
v, mTempRect);
}
if (v.requestFocus(direction, mTempRect)) {
playSoundEffect(SoundEffectConstants
.getContantForFocusDirection(direction));
return true;
}
}
// Give the focused view a last chance to handle the dpad key.
if (mView.dispatchUnhandledMove(focused, direction)) {
return true;
}
} else {
if (mView.restoreDefaultFocus()) {
return true;
}
}
}
return false;
}
View的focusSearch：
public View focusSearch(@FocusRealDirection int direction) {
if (mParent != null) {
return mParent.focusSearch(this, direction);
} else {
return null;
}
}
ViewGroup的focusSearch方法
@Override
public View focusSearch(View focused, int direction) {
if (isRootNamespace()) {
Log.d("MyRecycleView","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) {
Log.d("MyRecycleView","mParent != null");
return mParent.focusSearch(focused, direction);
}
return null;
}
FocusFinder 是真正寻找焦点的类。FocusFinder.getInstance().findNextFocus(this, focused, direction);
最终执行到：findNextFocusInAbsoluteDirection
View findNextFocusInAbsoluteDirection(ArrayList focusables, ViewGroup root, View focused,
Rect focusedRect, int direction) {
// initialize the best candidate to something impossible
// (so the first plausible view will become the best choice)
mBestCandidateRect.set(focusedRect);
//初始化mBestCandidateRect
switch(direction) {
case View.FOCUS_LEFT:
mBestCandidateRect.offset(focusedRect.width() + 1, 0);
break;
case View.FOCUS_RIGHT:
mBestCandidateRect.offset(-(focusedRect.width() + 1), 0);
break;
case View.FOCUS_UP:
mBestCandidateRect.offset(0, focusedRect.height() + 1);
break;
case View.FOCUS_DOWN:
mBestCandidateRect.offset(0, -(focusedRect.height() + 1));
}
View closest = null;
int numFocusables = focusables.size();
for (int i = 0; i < numFocusables; i++) {
View focusable = focusables.get(i);
// only interested in other non-root views
if (focusable == focused || focusable == root) continue;
// get focus bounds of other view in same coordinate system
focusable.getFocusedRect(mOtherRect);
root.offsetDescendantRectToMyCoords(focusable, mOtherRect);
if (isBetterCandidate(direction, focusedRect, mOtherRect, mBestCandidateRect)) {
mBestCandidateRect.set(mOtherRect);
closest = focusable;
}
}
return closest;
}
- focusables 当前布局 能获得焦点的view的集合
- 循环遍历focusables，mOtherRect 是每个View的Rect引用
- mBestCandidateRect 最能获取焦点的Rect
每个View都占有一个Rect 在坐标系上可以用（left,top）(right,bott0m)代表位置
isBetterCandidate 判断mOtherRect 能否作为获取焦点的候选人
/**
*
* @param savedInstanceState
* Rect source (当前占据焦点的view), Rect rect1(与rect2 作比较的 view，可能作为值 赋给rect2), Rect rect2（目前找到的下一个焦点位置）
* 寻找焦点:
* 1.
* 判断rect1 是否在source的右边，判断条件是
* srcRect.left < destRect.left || srcRect.right <= destRect.left)
* && srcRect.right < destRect.right
*
* 2.rect2 是否在source的右边,不是那么rect1 赋值给rect2 意味着rect1 是当前找到的最合适的下一个焦点的位置
*
*
* 3.rect1 和 rect2 都在 source 右边，比对俩个谁更加合适
* // if rect1 is to the direction of, and rect2 is not, rect1 wins.
* // for example, for direction left, if rect1 is to the left of the source
* // and rect2 is below, then we always prefer the in beam rect1, since rect2
* // could be reached by going down.
*
* 4.比较主轴 次轴距离
*
* long getWeightedDistanceFor(long majorAxisDistance, long minorAxisDistance) {
* return 13 * majorAxisDistance * majorAxisDistance
* + minorAxisDistance * minorAxisDistance;
* }
*
*/
boolean isBetterCandidate(int direction, Rect source, Rect rect1, Rect rect2) {
// to be a better candidate, need to at least be a candidate in the first
// place :)
if (!isCandidate(source, rect1, direction)) {
return false;
}
// we know that rect1 is a candidate.. if rect2 is not a candidate,
// rect1 is better
if (!isCandidate(source, rect2, direction)) {
return true;
}
// if rect1 is better by beam, it wins
if (beamBeats(direction, source, rect1, rect2)) {
return true;
}
// if rect2 is better, then rect1 cant' be :)
if (beamBeats(direction, source, rect2, rect1)) {
return false;
}
// otherwise, do fudge-tastic comparison of the major and minor axis
return (getWeightedDistanceFor(
majorAxisDistance(direction, source, rect1),
minorAxisDistance(direction, source, rect1)) // for循环下一个view的Rect
< getWeightedDistanceFor( 小于 代表最近
majorAxisDistance(direction, source, rect2),
minorAxisDistance(direction, source, rect2)));//当前最佳位置mBestCandidateRect
}
主轴距离的计算：
static int majorAxisDistance(int direction, Rect source, Rect dest) {
return Math.max(0, majorAxisDistanceRaw(direction, source, dest));
}
static int majorAxisDistanceRaw(int direction, Rect source, Rect dest) {
switch (direction) {
case View.FOCUS_LEFT:
return source.left - dest.right;
case View.FOCUS_RIGHT:
return dest.left - source.right;
case View.FOCUS_UP:
return source.top - dest.bottom;
case View.FOCUS_DOWN:
return dest.top - source.bottom;
}
throw new IllegalArgumentException("direction must be one of "
+ "{FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT}.");
}
次轴距离计算：
static int minorAxisDistance(int direction, Rect source, Rect dest) {
switch (direction) {
case View.FOCUS_LEFT:
case View.FOCUS_RIGHT:
// the distance between the center verticals
return Math.abs(
((source.top + source.height() / 2) -
((dest.top + dest.height() / 2))));
case View.FOCUS_UP:
case View.FOCUS_DOWN:
// the distance between the center horizontals
return Math.abs(
((source.left + source.width() / 2) -
((dest.left + dest.width() / 2))));
}
throw new IllegalArgumentException("direction must be one of "
+ "{FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT}.");
}