super_status_bar.xml是systemUI的一个总的布局文件。
下面是super_status_bar.xml的源码:
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"
android:focusable="true"
android:descendantFocusability="afterDescendants"
android:fitsSystemWindows="true"
android:background="@android:color/transparent"
>
android:layout_width="match_parent"
android:layout_height="@*android:dimen/status_bar_height"
/>
android:id="@+id/panel_holder"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
android:layout="@layout/quick_settings"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
从上面的源码可以知道,systemUI布局大概分为三个部分
第一:status_bar,这部分是状态栏。
第二:status_bar_expanded,这部分是下拉通知栏。
第三:quick_settings_stub,这部分是下拉快捷设置栏。
其中,本文中是重点分析下拉通知栏。
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下面是下拉通知栏的布局文件status_bar_expended.xml:
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"
android:id="@+id/notification_panel"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="@drawable/notification_panel_bg"
android:paddingTop="@dimen/notification_panel_padding_top"
android:layout_marginStart="@dimen/notification_panel_margin_left"
>
android:id="@+id/handle"
android:layout_width="match_parent"
android:layout_height="@dimen/close_handle_height"
android:background="@drawable/status_bar_close"
android:visibility="invisible"
/>
layout="@layout/carrier_label"
android:layout_height="@dimen/carrier_label_height"
android:layout_width="match_parent"
android:layout_marginBottom="@dimen/close_handle_height"
android:layout_gravity="bottom"
/>
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="@dimen/close_handle_underlap"
android:orientation="vertical"
android:animateLayoutChanges="false"
>
android:layout_width="match_parent"
android:layout_height="@dimen/notification_panel_header_height"
/>
android:id="@+id/emergency_calls_only"
android:textAppearance="@style/TextAppearance.StatusBar.Expanded.Network.EmergencyOnly"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:padding="4dp"
android:gravity="center"
android:visibility="gone"
/>
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
android:layout="@layout/flip_settings"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
android:id="@+id/scroll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fadingEdge="none"
android:overScrollMode="ifContentScrolls"
>
android:id="@+id/latestItems"
android:layout_width="match_parent"
android:layout_height="wrap_content"
systemui:rowHeight="@dimen/notification_row_min_height"
/>
其中,代码段: android:layout_width="match_parent"
android:layout_height="@dimen/notification_panel_header_height"
/>
该代码段是下拉通知栏的顶部的布局,包括时间,日期和一个清除通知消息的按钮。
代码段: android:id="@+id/latestItems"
android:layout_width="match_parent"
android:layout_height="wrap_content"
systemui:rowHeight="@dimen/notification_row_min_height"
/>
该代码段是用于存放下拉通知栏里面的各种通知消息。
下面主要分析com.android.systemui.statusbar.phone.NotificationPanelView下拉通知栏的实现类的源码:
public class NotificationPanelView extends PanelView {};由类定义的代码可以知道该类是继承PanelView类,PanelView类则是继承于FrameLayout。
下拉菜单栏的主要实现都是在NotificationPanelView的父类PanelView中实现。
看以下的代码段:
protected void onFinishInflate() {
super.onFinishInflate();
mHandleView = findViewById(R.id.handle);
loadDimens();
if (DEBUG) logf("handle view: " + mHandleView);
if (mHandleView != null) {
mHandleView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
Log.i("Garment30", "onTouch");
int pointerIndex = event.findPointerIndex(mTrackingPointer);
if (pointerIndex < 0) {
pointerIndex = 0;
mTrackingPointer = event.getPointerId(pointerIndex);
}
final float y = event.getY(pointerIndex);
final float rawDelta = event.getRawY() - event.getY();
final float rawY = y + rawDelta;
if (DEBUG) logf("handle.onTouch: a=%s p=[%d,%d] y=%.1f rawY=%.1f off=%.1f",
MotionEvent.actionToString(event.getAction()),
mTrackingPointer, pointerIndex,
y, rawY, mTouchOffset);
PanelView.this.getLocationOnScreen(mAbsPos);
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
Log.i("Garment30", "ACTION_DOWN");
mTracking = true;
mHandleView.setPressed(true);
postInvalidate(); // catch the press state change
mInitialTouchY = y;
mVelocityTracker = FlingTracker.obtain();
trackMovement(event);
mTimeAnimator.cancel(); // end any outstanding animations
mBar.onTrackingStarted(PanelView.this);
mTouchOffset = (rawY - mAbsPos[1]) - mExpandedHeight;
if (mExpandedHeight == 0) {
mJustPeeked = true;
runPeekAnimation();
}
break;
case MotionEvent.ACTION_POINTER_UP:
Log.i("Garment30", "ACTION_POINTER_UP");
final int upPointer = event.getPointerId(event.getActionIndex());
if (mTrackingPointer == upPointer) {
// gesture is ongoing, find a new pointer to track
final int newIndex = event.getPointerId(0) != upPointer ? 0 : 1;
final float newY = event.getY(newIndex);
final float newRawY = newY + rawDelta;
mTrackingPointer = event.getPointerId(newIndex);
mTouchOffset = (newRawY - mAbsPos[1]) - mExpandedHeight;
mInitialTouchY = newY;
}
break;
case MotionEvent.ACTION_MOVE:
Log.i("Garment30", "ACTION_MOVE");
Log.i("Garment28", "PanelView---ACTION_MOVE");
final float h = rawY - mAbsPos[1] - mTouchOffset;
if (h > mPeekHeight) {
Log.i("Garment28", "PanelView---h > mPeekHeight");
if (mPeekAnimator != null && mPeekAnimator.isStarted()) {
mPeekAnimator.cancel();
}
mJustPeeked = false;
}
if (!mJustPeeked) {
Log.i("Garment28", "PanelView---!mJustPeeked--h:"+h);
//下面两段代码需要同时使用
PanelView.this.setExpandedHeightInternal(h);//屏蔽了这段代码,下拉菜单无法随手的移动一起下拉,松手后菜单移动到默认的长度
mBar.panelExpansionChanged(PanelView.this, mExpandedFraction);//屏蔽了这段代码,下拉通知栏显示为透明,松手后才正常
}
trackMovement(event);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
Log.i("Garment30", "ACTION_CANCEL");
mFinalTouchY = y;
mTracking = false;
mTrackingPointer = -1;
mHandleView.setPressed(false);
postInvalidate(); // catch the press state change
mBar.onTrackingStopped(PanelView.this);
trackMovement(event);
float vel = 0, yVel = 0, xVel = 0;
boolean negative = false;
if (mVelocityTracker != null) {
// the velocitytracker might be null if we got a bad input stream
mVelocityTracker.computeCurrentVelocity(1000);
yVel = mVelocityTracker.getYVelocity();
negative = yVel < 0;
xVel = mVelocityTracker.getXVelocity();
if (xVel < 0) {
xVel = -xVel;
}
if (xVel > mFlingGestureMaxXVelocityPx) {
xVel = mFlingGestureMaxXVelocityPx; // limit how much we care about the x axis
}
vel = (float)Math.hypot(yVel, xVel);
if (vel > mFlingGestureMaxOutputVelocityPx) {
vel = mFlingGestureMaxOutputVelocityPx;
}
mVelocityTracker.recycle();
mVelocityTracker = null;
}
// if you've barely moved your finger, we treat the velocity as 0
// preventing spurious flings due to touch screen jitter
final float deltaY = Math.abs(mFinalTouchY - mInitialTouchY);
if (deltaY < mFlingGestureMinDistPx
|| vel < mFlingExpandMinVelocityPx
) {
vel = 0;
}
if (negative) {
vel = -vel;
}
if (DEBUG) logf("gesture: dy=%f vel=(%f,%f) vlinear=%f",
deltaY,
xVel, yVel,
vel);
fling(vel, true); //松手后下拉通知栏回弹的动画
break;
}
return true;
}});
}
}
其中,mHandleView = findViewById(R.id.handle);代码用于初始化下拉通知栏最下面的那一条直线,可以知道该view的触摸事件用于控制下拉通知栏的拉动时的高度的变化。
在MotionEvent.ACTION_MOVE事件中PanelView.this.setExpandedHeightInternal(h);这段代码实现了拉动过程在中下拉通知栏的大小的改变,传入的h变量就是下拉通知栏的高度。看该方法的实现:
public void setExpandedHeightInternal(float h) {
if (Float.isNaN(h)) {
// If a NaN gets in here, it will freeze the Animators.
if (DEBUG_NAN) {
Log.v(TAG, "setExpandedHeightInternal: warning: h=NaN, using 0 instead",
new Throwable());
}
h = 0;
}
float fh = getFullHeight();
if (fh == 0) {
// Hmm, full height hasn't been computed yet
}
if (h < 0) h = 0;
if (!(mRubberbandingEnabled && (mTracking || mRubberbanding)) && h > fh) h = fh;
mExpandedHeight = h; //更新最新的通知栏的长度,屏蔽了这段代码,通知栏无法拉出
if (DEBUG) logf("setExpansion: height=%.1f fh=%.1f tracking=%s rubber=%s", h, fh, mTracking?"T":"f", mRubberbanding?"T":"f");
Log.i("Garment30", "PanelView---setExpandedHeightInternal--h:"+h);
requestLayout(); //触发OnMeasure()和onLayout()进行View的重绘, 屏蔽这段代码,下拉通知栏无法显示,初始时h=0,默认状态时,h=729,最大为1919
// FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) getLayoutParams();
// lp.height = (int) mExpandedHeight;
// setLayoutParams(lp);
mExpandedFraction = Math.min(1f, (fh == 0) ? 0 : h / fh);
}
在setExpandedHeightInternal()函数中,mExpandedHeight = h;这段代码用于更新需要重画的最新的下拉菜单栏的高度。
requestLayout();该函数触发了OnMeasure()和onLayout()函数,对该View进行重新测量并重新布局。
当手松开的时候,通知栏会有一个回弹的动作,看到fling(vel, true);这段代码:
public void fling(float vel, boolean always) {
if (DEBUG) logf("fling: vel=%.3f, this=%s", vel, this);
mVel = vel;
if (always||mVel != 0) {
animationTick(0); // begin the animation 开始执行回弹的动画
}
}
其中animationTick(0);是回弹动画的实现方法:
private void animationTick(long dtms) {
if (!mTimeAnimator.isStarted()) {
// XXX HAX to work around bug in TimeAnimator.end() not resetting its last time
mTimeAnimator = new TimeAnimator();
mTimeAnimator.setTimeListener(mAnimationCallback);
if (mPeekAnimator != null) mPeekAnimator.cancel();
mTimeAnimator.start();
mRubberbanding = mRubberbandingEnabled // is it enabled at all?
&& mExpandedHeight > getFullHeight() // are we past the end?
&& mVel >= -mFlingGestureMinDistPx; // was this not possibly a "close" gesture?
if (mRubberbanding) {
mClosing = true;
} else if (mVel == 0) {
// if the panel is less than halfway open, close it
mClosing = (mFinalTouchY / getFullHeight()) < 0.5f;
} else {
mClosing = mExpandedHeight > 0 && mVel < 0;
}
} else if (dtms > 0) {
final float dt = dtms * 0.001f; // ms -> s
if (DEBUG) logf("tick: v=%.2fpx/s dt=%.4fs", mVel, dt);
if (DEBUG) logf("tick: before: h=%d", (int) mExpandedHeight);
final float fh = getFullHeight();
boolean braking = false;
if (BRAKES) {
if (mClosing) {
braking = mExpandedHeight <= mCollapseBrakingDistancePx;
mAccel = braking ? 10*mCollapseAccelPx : -mCollapseAccelPx;
} else {
braking = mExpandedHeight >= (fh-mExpandBrakingDistancePx);
mAccel = braking ? 10*-mExpandAccelPx : mExpandAccelPx;
}
} else {
mAccel = mClosing ? -mCollapseAccelPx : mExpandAccelPx;
}
mVel += mAccel * dt;
if (braking) {
if (mClosing && mVel > -mBrakingSpeedPx) {
mVel = -mBrakingSpeedPx;
} else if (!mClosing && mVel < mBrakingSpeedPx) {
mVel = mBrakingSpeedPx;
}
} else {
if (mClosing && mVel > -mFlingCollapseMinVelocityPx) {
mVel = -mFlingCollapseMinVelocityPx;
} else if (!mClosing && mVel > mFlingGestureMaxOutputVelocityPx) {
mVel = mFlingGestureMaxOutputVelocityPx;
}
}
float h = mExpandedHeight + mVel * dt;
if (mRubberbanding && h < fh) {
h = fh;
}
if (DEBUG) logf("tick: new h=%d closing=%s", (int) h, mClosing?"true":"false");
Log.i("Garment30", "PanelView---animationTick--h:"+h); //end at 729
setExpandedHeightInternal(h);
mBar.panelExpansionChanged(PanelView.this, mExpandedFraction);
if (mVel == 0
|| (mClosing && mExpandedHeight == 0)
|| ((mRubberbanding || !mClosing) && mExpandedHeight == fh)) {
post(mStopAnimator); //回弹动画停止
}
} else {
Log.v(TAG, "animationTick called with dtms=" + dtms + "; nothing to do (h="
+ mExpandedHeight + " v=" + mVel + ")");
}
}
可以看到,setExpandedHeightInternal(h); mBar.panelExpansionChanged(PanelView.this, mExpandedFraction);该方法中有调用这两个方法对下拉菜单栏的长度进行更新的操作。mTimeAnimator = new TimeAnimator();mTimeAnimator.setTimeListener(mAnimationCallback);也初始化了一个TimeAnimator对象,并设置了监听器。
private final TimeListener mAnimationCallback = new TimeListener() {
@Override
public void onTimeUpdate(TimeAnimator animation, long totalTime, long deltaTime) {
animationTick(deltaTime);
}
};
该监听器中的回调函数调用了animationTick(deltaTime)下拉通知栏的回弹动画的方法,所以我们松开手后通知栏会有一个回弹的动作。
当满足一定条件时,回弹动画停止。
if (mVel == 0|| (mClosing && mExpandedHeight == 0)|| ((mRubberbanding || !mClosing) && mExpandedHeight == fh)) {
post(mStopAnimator); //回弹动画停止
}
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注意:下拉快捷设置栏的实现和下拉通知栏的实现是差不多,只是装载的内容不同。所以也可以通过类似的方法来分析下拉快速设置栏。