I'm making some progress on using the GestureDetector to start scrolls
and flings for a custom view.
I am using View.scrollBy(x,y) and Scroller.fling in response to
Gestures.
I have a hopefully simple question, though, how do I know when the
scroll/fling is over?
I want to take some action at this point, start recreating the views
buffer and then rest the scroll to (0,0).
But I am uncertain when to do that. GestureDetector doesn't give me
the UP event. I could capture that separately even while most motion
events are consumed by the detector.
This is evidence enough that a scroll is finished, but a fling may
still be in progress. Sure I can check Scroller.isFinished() here,
but if isn't done, how will I get an event when it is?
@Override
public boolean onTouchEvent(MotionEvent event) {
//let the touch event be handled by the GestureDetector
boolean handled= this.detector.onTouchEvent(event);
if(event.getAction()==MotionEvent.ACTION_UP)
{
//be done with scrolling or flinging
//recreate view buffer
//reset scroll
}
if(!handled)
return super.onTouchEvent(event);
else
return true;
}
Here's the Gesture Listener code.
/*
* (non-Javadoc)
* @see android.view.GestureDetector.OnGestureListener#onDown
(android.view.MotionEvent)
*/
@Override
public boolean onDown(MotionEvent arg0) {
// TODO Auto-generated method stub
return true;
}
/*
* (non-Javadoc)
* @see android.view.GestureDetector.OnGestureListener#onFling
(android.view.MotionEvent, android.view.MotionEvent, float, float)
*/
@Override
public boolean onFling(MotionEvent arg0, MotionEvent arg1, float
velocityX,
float velocityY) {
mScroller.fling(getScrollX(), getScrollY(), (int)(-2*velocityX),
(int)(-2*velocityY), -10000, 10000, -10000, 10000);
return false;
}
/*
* (non-Javadoc)
* @see android.view.GestureDetector.OnGestureListener#onLongPress
(android.view.MotionEvent)
*/
@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
/*
* (non-Javadoc)
* @see android.view.GestureDetector.OnGestureListener#onScroll
(android.view.MotionEvent, android.view.MotionEvent, float, float)
*/
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float
distanceX,
float distanceY) {
this.scrollBy((int)distanceX, (int)distanceY);
return true;
}
/*
* (non-Javadoc)
* @see android.view.GestureDetector.OnGestureListener#onShowPress
(android.view.MotionEvent)
*/
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
/*
* (non-Javadoc)
* @see android.view.GestureDetector.OnGestureListener#onSingleTapUp
(android.view.MotionEvent)
*/
@Override
public boolean onSingleTapUp(MotionEvent e) {
// Auto-generated method stub
return false;
}
This method does get a call during a scroll, but not during a fling,
and it's while the scroll is in progress, not finished.
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
}
Thanks for any advice. I have checked the archives on this question
and didn't find a solution.
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