基于Android 13,Launcher3实现需求：
1. 长按Hotseat的图标显示红色删除角标
2. 点击角标，删除图标并保存到Database
3.点击其他地方，取消编辑hotseat图标模式
实现效果：
实现原理：
图标是由BubbleTextView来是实现的，是一个TextView，要增加角标应该有几种思路：
1.TextView可以设置 left top bottom right 4个drawable，top已经用作实际的icon，这个应该布局不了
2. 修改背景background,在适当的时候修改background？
3.重写TextView的onDraw,适当的时候在原来的基础上画出额外的角标
查看Android13原生的Launcher代码发现 BubbleTextView的onDraw已经有DotRenderer的实现，显示的应该是应用通知，因此模仿这个实现思路即可。
查看源码发现实际使用的是DoubleShadowBubbleTextView.java，调用到的是ondraw调用的是drawWithoutDot
因此在BubbleTextView.java中添加代码即可实现：
protected void drawWithoutDot(Canvas canvas) {super.onDraw(canvas);drawMyDotIfNecessary(canvas);
}protected void drawMyDotIfNecessary(Canvas canvas){if(!mIsDeleteHidden) {Paint paint = new Paint();paint.setColor(Color.RED); // 角标颜色paint.setStyle(Paint.Style.FILL);canvas.drawCircle(getWidth() - 30f, 30f, 30f, paint);}
}
接下来应该需要实现在什么时候显示圆点操作，
比方说长按某一个hotseat里图标，则所有的view都添加这个圆点
长按图标事件可以得到，在什么时候取消呢？点击图标非圆点处取消。
接下来实现，点击圆点事件：把点击事件传到mHotseatController里删除并更新hotseat里的view
step1: 在BubbleTextView.java里实现onDraw画图，捕捉点击圆点事件，实现显示隐藏角标接口
private boolean mIsDeleteHidden = true;//Kevin.Ye added
private boolean mIsDownInDotErea = false;//
private Rect mRectDotBounds = null;//
private OnDotClkListener mOnDotClkListener = null;
//Kevin.Ye added end@Overridepublic boolean onTouchEvent(MotionEvent event) {// ignore events if they happen in padding areaif(cancelDotIfNecessary(event))//added by Kevin.Ye case when Dot is shownreturn true;//endif (event.getAction() == MotionEvent.ACTION_DOWN&& shouldIgnoreTouchDown(event.getX(), event.getY())) {return false;}if (isLongClickable()) {super.onTouchEvent(event);mLongPressHelper.onTouchEvent(event);// Keep receiving the rest of the eventsreturn true;} else {return super.onTouchEvent(event);}}
private boolean cancelDotIfNecessary(MotionEvent event){if(isMyDotHidden())return false;switch (event.getAction()){case MotionEvent.ACTION_DOWN:if(isTouchInDotErea((int)event.getX(),(int)event.getY())) {mIsDownInDotErea = true;return true;}break;case MotionEvent.ACTION_UP:if(mIsDownInDotErea){mIsDownInDotErea = false;if(isTouchInDotErea((int)event.getX(),(int)event.getY())){onClkMyDot();return true;}else{Log.d("dot","touch up elsewhere");}}break;}return false;}private boolean isTouchInDotErea(int x,int y){Log.d("dot","touch x:"+x+" y:"+y);if(mRectDotBounds == null) {mRectDotBounds = new Rect(getWidth() - 60, 0, getWidth(), 60);}return mRectDotBounds.contains(x,y);}private void onClkMyDot(){Log.d("dot","onClkMyDot");if(mOnDotClkListener != null)mOnDotClkListener.onClkIconDot(BubbleTextView.this);}public interface OnDotClkListener{void onClkIconDot(View view);}public void setOnDotClkListener(OnDotClkListener onDotClkListener){mOnDotClkListener = onDotClkListener;}
/**draw my dot for deleting or added icon Kevin.Ye*/private boolean isMyDotHidden(){return mIsDeleteHidden;}public void setDeleteDotHidden(boolean hide){mIsDeleteHidden = hide;invalidate();}protected void drawMyDotIfNecessary(Canvas canvas){if(!mIsDeleteHidden) {Paint paint = new Paint();paint.setColor(Color.RED); // 角标颜色 paint.setStyle(Paint.Style.FILL);canvas.drawCircle(getWidth() - 30f, 30f, 30f, paint);}}
step2： HotseatController.java（注意本类是源码没有的），实现显示角标、取消显示角标、响应删除图标三个接口
private boolean mIsInDeletingMode = false;public boolean isInDeletingMode(){return mIsInDeletingMode;}public void showHotseatDeleteDot(){mIsInDeletingMode = true;Hotseat hs = mLauncher.getHotseat();int gridCount = getGridCount(mLauncher);//ArrayList<View> views = new ArrayList<>();for (int i = 0; i < gridCount; i++) {int cx = hs.getCellXFromOrder(i);int cy = hs.getCellYFromOrder(i);View v = hs.getShortcutsAndWidgets().getChildAt(cx, cy);if (hs.isOccupied(cx, cy)) {if (v != null) {if(v instanceof BubbleTextView){Log.d("dot","v instanceof BubbleTextView!!!");((BubbleTextView)v).setDeleteDotHidden(false);((BubbleTextView)v).setOnDotClkListener(mOnDotClkListener);}}}}}public void cancelDeletingMode(){mIsInDeletingMode = false;Hotseat hs = mLauncher.getHotseat();int gridCount = getGridCount(mLauncher);//ArrayList<View> views = new ArrayList<>();for (int i = 0; i < gridCount; i++) {int cx = hs.getCellXFromOrder(i);int cy = hs.getCellYFromOrder(i);View v = hs.getShortcutsAndWidgets().getChildAt(cx, cy);if (hs.isOccupied(cx, cy)) {if (v != null) {if(v instanceof BubbleTextView){Log.d("dot","v instanceof BubbleTextView!!!");((BubbleTextView)v).setDeleteDotHidden(true);}}}}}BubbleTextView.OnDotClkListener mOnDotClkListener = new BubbleTextView.OnDotClkListener() {@Overridepublic void onClkIconDot(View view) {Log.d("dot","HotseatController onClkMyDot");Hotseat hs = mLauncher.getHotseat();hs.removeView(view);//Log.d("dot","view.getTag() :"+view.getTag().toString());Object tag = view.getTag();WorkspaceItemInfo info = tag instanceof WorkspaceItemInfo ? (WorkspaceItemInfo) tag : null;if(info != null) {mLauncher.getModelWriter().deleteItemFromDatabase(info,null);}}};step3:Launcher.java中增加调用取消编辑hotseat模式（隐藏角标）
private HotseatController mHotseatController = null;//Kevin.YemHotseatController = new HotseatController(this.getApplicationContext(),this);//Kevin.Ye/***Return HotseatController Kevin.Ye added*/
public HotseatController getHotseatController(){return mHotseatController;
}@Overridepublic boolean startActivitySafely(View v, Intent intent, ItemInfo item) {/*Kevin.Ye added for cancel deleting mode*/if(getHotseatController().isInDeletingMode()){getHotseatController().cancelDeletingMode();return true;}}step4:src/com/android/launcher3/Workspace.java 中的接口DragView beginDragShared
实现长按进入Hotseat图标编辑模式（显示删除角标）
if (child.getParent() instanceof ShortcutAndWidgetContainer) {mDragSourceInternal = (ShortcutAndWidgetContainer) child.getParent();}if (child instanceof BubbleTextView && !dragOptions.isAccessibleDrag) {//Kevin.Ye added for showing hotseat edit modeboolean bStartLongPressAction = true;if(child.getParent() instanceof ShortcutAndWidgetContainer)if(child.getParent().getParent() instanceof Hotseat){mLauncher.getHotseatController().showHotseatDeleteDot();bStartLongPressAction = false;}//add endif(bStartLongPressAction)dragOptions.preDragCondition = ((BubbleTextView) child).startLongPressAction();}后续应该用加载drawable的方式来代替drawCircle画图，删除图标后应该重新排布热座上的图标。
