Dropping event due to no window focus 窗口失去焦点，如何恢复

在跳转界面的瞬间，切换到桌面，然后重现进入，整个窗口失去焦点，

log如下：
W/ViewRootImpl[PlayActivity]: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=693.0, y[0]=853.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=1729106, downTime=1728988, deviceId=1, source=0xd002 }

W/ViewRootImpl[PlayActivity]: Dropping event due to no window focus: MotionEvent { action=ACTION_DOWN, actionButton=0, id[0]=0, x[0]=808.0, y[0]=716.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=1747499, downTime=1747499, deviceId=1, source=0xd002 }

在我的情况下，类似的问题是由在任何地方使用 onKeyDown()引起的，包括在按键上显示对话框时。使用 onKeyUp() 显示对话框和活动为我解决了这个问题。