@Override
  public boolean onTouchEvent(MotionEvent event) {
    if (mDraweeHolder.onTouchEvent(event)) {
      return true;
    }
    return super.onTouchEvent(event);
  }
Does the actual work of detaching.

<p>Non-test subclasses should NOT override. Use onDetach for custom code.
drawee/src/main/java/com/facebook/drawee/view/DraweeView.java