我关注thedochere在绘图时捕获Pixelbook笔上按下的按钮，但永远不会抛出TOOL_TYPE_ERASER事件。当我尝试打印日志时，我看不出按住和松开按钮有什么区别:onTouchEvent:MotionEvent{action=ACTION_DOWN,actionButton=0,id[0]=0,x[0]=2010.4766,y[0]=778.10156,toolType[0]=TOOL_TYPE_STYLUS,buttonState=0,metaState=0,flags=0x0,edgeFlags=0x0,pointerCount=1,historySize=0,ev