前言:让生活每天都充满憧憬,而不是日复一日的重复,学会用孩子的眼光看待这个世界。
效果图
现象:
下拉中间的白色的按钮没有反应。正常情况下下拉是可以的。
这个控件的触摸事件没有反应。通过对系统app SystemUI的学习,了解到这个控件叫做DividerView,属于多窗口模式下的一个分割两个Activity的view组件
code在
Z:\frameworks\base\packages\SystemUI\src\com\android\systemui\stackdivider
从布局文件
<com.android.systemui.stackdivider.DividerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent">
<View
style="@style/DockedDividerBackground"
android:id="@+id/docked_divider_background"
android:background="@color/docked_divider_background"/>
<com.android.systemui.stackdivider.MinimizedDockShadow
style="@style/DockedDividerMinimizedShadow"
android:id="@+id/minimized_dock_shadow"
android:alpha="0"/>">
<com.android.systemui.stackdivider.DividerHandleView
style="@style/DockedDividerHandle"
android:id="@+id/docked_divider_handle"
android:contentDescription="@string/accessibility_divider"
android:background="@null"/>
</com.android.systemui.stackdivider.DividerView>
得出这DividerView(分割线的黑色部分)、DividerHandleView(f分割线的白色部分)一个相当于ViewGroup(onTouchEvent、dispatchTouchEvent、onInterceptTouchEvent),一个是View(onTouchEvent、dispatchTouchEvent)。
看一下code
/**
* View for the handle in the docked stack divider.
*/
public class DividerHandleView extends View{
...
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
Log.d("elliotlog","DividerHandleView onTouchEvent");
return super.onTouchEvent(event);
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
Log.d("elliotlog","DividerHandleView dispatchTouchEvent");
return super.dispatchTouchEvent(event);
}
...
}
public class DividerView extends FrameLayout implements OnTouchListener{
...
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
Log.d("elliotlog","DividerView onTouchEvent");
return onTouch(mHandle,event);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
Log.d("elliotlog","DividerView onInterceptTouchEvent");
return super.onInterceptTouchEvent(ev);
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
Log.d("elliotlog","DividerView dispatchTouchEvent");
boolean flag=super.dispatchTouchEvent(ev);
if(flag){Log.d("elliotlog","is DividerView dispatchTouchEvent");}else{Log.d("elliotlog","not DividerView dispatchTouchEvent");}
return flag;
}
//拖拽效果实现会调用的方法
public boolean onTouch(View v, MotionEvent event) {
Log.d("elliotlog","onTouch");
convertToScreenCoordinates(event);
mGestureDetector.onTouchEvent(event);
final int action = event.getAction() & MotionEvent.ACTION_MASK
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.d("elliotlog","MotionEvent.ACTION_DOWN:"+MotionEvent.ACTION_DOWN);
mVelocityTracker = VelocityTracker.obtain();
mVelocityTracker.addMovement(event);
mStartX = (int) event.getX();
mStartY = (int) event.getY();
boolean result = startDragging(true /* animate */, true /* touching */);
if (!result) {
// Weren't able to start dragging successfully, so cancel it again.
stopDragging();
}
mStartPosition = getCurrentPosition();
mMoving = false;
return result;
case MotionEvent.ACTION_MOVE:
Log.d("elliotlog","MotionEvent.ACTION_MOVE:"+MotionEvent.ACTION_MOVE);
mVelocityTracker.addMovement(event);
int x = (int) event.getX();
int y = (int) event.getY();
boolean exceededTouchSlop =
isHorizontalDivision() && Math.abs(y - mStartY) > mTouchSlop
|| (!isHorizontalDivision() && Math.abs(x - mStartX) > mTouchSlop);
if (!mMoving && exceededTouchSlop) {
mStartX = x;
mStartY = y;
mMoving = true;
}
if (mMoving && mDockSide != WindowManager.DOCKED_INVALID) {
SnapTarget snapTarget = mSnapAlgorithm.calculateSnapTarget(
mStartPosition, 0 /* velocity */, false /* hardDismiss */);
resizeStack(calculatePosition(x, y), mStartPosition, snapTarget);
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
Log.d("elliotlog","MotionEvent.ACTION_UP:"+MotionEvent.ACTION_UP);
mVelocityTracker.addMovement(event);
x = (int) event.getRawX();
y = (int) event.getRawY();
mVelocityTracker.computeCurrentVelocity(1000);
int position = calculatePosition(x, y);
stopDragging(position, isHorizontalDivision() ? mVelocityTracker.getYVelocity()
: mVelocityTracker.getXVelocity(), false /* avoidDismissStart */,
true /* log */);
mMoving = false;
break;
}
return true;
}
...
}
点击DividerHandleView,并且尝试向下滑动。log打印如下
03-02 04:38:33.973 D/elliotlog( 1403): DividerView dispatchTouchEvent
03-02 04:38:33.973 D/elliotlog( 1403): DividerView onTouchEvent
03-02 04:38:33.973 D/elliotlog( 1403): not DividerView dispatchTouchEvent
03-02 04:38:35.030 D/elliotlog( 1403): DividerView dispatchTouchEvent
03-02 04:38:35.030 D/elliotlog( 1403): DividerView onTouchEvent
03-02 04:38:35.030 D/elliotlog( 1403): not DividerView dispatchTouchEvent
会发现连onInterceptTouchEvent事件都没有执行。而是DividerView分发了之后就直接自己消费掉了onTouchEvent。
这显然不符合我们正常的逻辑,当我们不复现这个bug时,会发现打印的很正常
03-02 06:00:31.919 D/elliotlog( 1397): DividerView dispatchTouchEvent
03-02 06:00:31.919 D/elliotlog( 1397): DividerView onInterceptTouchEvent
03-02 06:00:31.919 D/elliotlog( 1397): DividerHandleView dispatchTouchEvent
03-02 06:00:31.920 D/elliotlog( 1397): onTouch
03-02 06:00:31.920 D/elliotlog( 1397): MotionEvent.ACTION_DOWN:0
03-02 06:00:31.922 D/elliotlog( 1397): is DividerView dispatchTouchEvent
03-02 06:00:32.045 D/elliotlog( 1397): DividerView dispatchTouchEvent
03-02 06:00:32.045 D/elliotlog( 1397): DividerView onInterceptTouchEvent
03-02 06:00:32.045 D/elliotlog( 1397): DividerHandleView dispatchTouchEvent
03-02 06:00:32.045 D/elliotlog( 1397): onTouch
03-02 06:00:32.046 D/elliotlog( 1397): MotionEvent.ACTION_MOVE:2
首先是DividerView dispatchTouchEvent,然后内部会调用onInterceptTouchEvent,于是子View DividerHandleView会分发dispatchTouchEvent,view是没有onInterceptTouchEvent,即不会拦截 ,内部会调用 OnTouchListener的onTouch,上面贴的代码中这个方法返回了ture。消费了,所以子view的onTouchEvent方法不会执行了。
回到原点,我们还是要分析错误的情况。
我们发现,在Divider.java中存在这样的一个监听接口,
class DockDividerVisibilityListener extends IDockedStackListener.Stub {
...
@Override
public void onAdjustedForImeChanged(boolean adjustedForIme, long animDuration)
throws RemoteException {
mView.post(() -> {
if (mAdjustedForIme != adjustedForIme) {
mAdjustedForIme = adjustedForIme;
updateTouchable();
if (!mMinimized) {
if (animDuration > 0) {
mView.setAdjustedForIme(adjustedForIme, animDuration);
} else {
mView.setAdjustedForIme(adjustedForIme);
}
}
}
});
}
...
}
private void updateTouchable() {
mWindowManager.setTouchable(!mMinimized && !mAdjustedForIme);
}
也就说当Divider最小化,或者需要调整(如出现输入法时)会设为不可触摸(由framework层控制),这就出现了刚才的分发机制不符合规矩的做法,从而出现这个bug。
着个监听器是如何注册的
在Divider.java(SystemUI)
SystemServicesProxy ssp = Recents.getSystemServices();
ssp.registerDockedStackListener(mDockDividerVisibilityListener);
在SystemServicesProxy.java中(SystemUI)
public void registerDockedStackListener(IDockedStackListener listener) {
if (mWm == null) return;
try {
WindowManagerGlobal.getWindowManagerService().registerDockedStackListener(listener);
} catch (Exception e) {
e.printStackTrace();
}
}
在WindowManagerService.java(framework)
@Override
public void registerDockedStackListener(IDockedStackListener listener) {
if (!checkCallingPermission(android.Manifest.permission.REGISTER_WINDOW_MANAGER_LISTENERS,
"registerDockedStackListener()")) {
return;
}
// TODO(multi-display): The listener is registered on the default display only.
getDefaultDisplayContentLocked().mDividerControllerLocked.registerDockedStackListener(
listener);
}
在DockedStackDividerController.java
void registerDockedStackListener(IDockedStackListener listener) {
mDockedStackListeners.register(listener);
notifyDockedDividerVisibilityChanged(wasVisible());
notifyDockedStackExistsChanged(
mDisplayContent.mService.mStackIdToStack.get(DOCKED_STACK_ID) != null);
notifyDockedStackMinimizedChanged(mMinimizedDock, 0 /* animDuration */);
notifyAdjustedForImeChanged(mAdjustedForIme, 0 /* animDuration */);
}
notifyAdjustedForImeChanged
void notifyAdjustedForImeChanged(boolean adjustedForIme, long animDuration) {
final int size = mDockedStackListeners.beginBroadcast();
for (int i = 0; i < size; ++i) {
final IDockedStackListener listener = mDockedStackListeners.getBroadcastItem(i);
try {
listener.onAdjustedForImeChanged(adjustedForIme, animDuration);
} catch (RemoteException e) {
Slog.e(TAG_WM, "Error delivering adjusted for ime changed event.", e);
}
}
mDock
这里面完成了注册