Agfdhyk

In my application I have a VideoView that display a video feed coming from a camera pool. I wish to use gesture recognition to change which camera is being shown.
Scrolling on X axis should change camera type, scrolling on Y axis should switch the side of the camera group.

Source (of the MainActivity object where the VideoView is located):

private GestureDetectorCompat gestureDetector;



@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);



    gestureDetector = new GestureDetectorCompat(this, new CameraGestureListener());



    cameraView = findViewById(R.id.cameraView);



    cameraView.setOnTouchListener(new View.OnTouchListener() {

        @Override

        public boolean onTouch(View view, MotionEvent motionEvent) {

            if (gestureDetector.onTouchEvent(motionEvent))

                return true;



            return MainActivity.super.onTouchEvent(motionEvent);

        }

    });

And finally I defined this class (inside MainActivity):

class CameraGestureListener extends GestureDetector.SimpleOnGestureListener {

    @Override

    public boolean onDown(MotionEvent event) {

        Log.d(getClass().getName(), "onDown: " + event.toString());

        return true;

    }



    @Override

    public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {

        if(Math.abs(velocityY)>Math.abs(velocityX))

        {

            Log.d(getClass().getName(), "change side");

        }

        else if(velocityX>0)

        {

            Log.d(getClass().getName(), "change camera type");

        }

        else if(velocityX<0)

        {

            Log.d(getClass().getName(), "change camera type");

        }



        return true;

    }



    @Override

    public boolean onScroll(MotionEvent event1, MotionEvent event2, float distanceX, float distanceY) {

        if(Math.abs(distanceY)>Math.abs(distanceX))

        {

            Log.d(getClass().getName(), "change side");

        }

        else if(distanceX>0)

        {

            Log.d(getClass().getName(), "change camera type");

        }

        else if(distanceX<0)

        {

            Log.d(getClass().getName(), "change camera type");

        }



        return true;

    }

}

In debug I can clearly see that Scroll events are triggered twice and often distanceX is larger than distanceY even if the gesture is mainly on the physical Y screen axis. Same problems arise with similar behaviours on Fling events.
How can I fix this?

Following pskink suggestion the only needed fix was to remove the unneeded retrigger of the superclass event handler (a cut&paste misprint of my own):

MainActivity.super.onTouchEvent(motionEvent);

The correct code become:

cameraView.setOnTouchListener(new View.OnTouchListener() {

    @Override

    public boolean onTouch(View view, MotionEvent motionEvent) {

        gestureDetector.onTouchEvent(motionEvent);



        return true;

    }

});

The gesture is properly recognized by onFling event handler. Trough onScroll event handlers you still observe two events for each gesture but it's probably a correct behaviour.