Android-dispatchTouchEvent 没有捕捉到 ACTION_CANCEL

Question

I am overriding dispatchTouchEvent() method to detect each and every touch in an activity.

 @Override
public boolean dispatchTouchEvent(MotionEvent event) {
    System.out.println("android test "+event.toString());
    return super.dispatchTouchEvent(event);
}

But this method is catching only ACTION_UP,ACTION_DOWN and ACTION_MOVE events,not ACTION_CANCEL event. What may be the reason for this ?

Answer 1

@pskink's answer is correct. ie ACTION_CANCEL is a system event.

"ACTION_CANCEL occurs when the parent takes possession of the motion, for example when the user has dragged enough across a list view that it will start scrolling instead of letting you press the buttons inside of i.

http://developer.android.com/reference/android/view/ViewGroup.html#onInterceptTouchEvent%28android.view.MotionEvent%29