GestureDetectorCompact not working?

Question

My code

 public class TestActivity extends AppCompatActivity implements GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);

        GestureDetectorCompat gestureDetectorCompat=new GestureDetectorCompat(this,this);
        gestureDetectorCompat.setOnDoubleTapListener(this);
    }

    @Override
    public boolean onDown(MotionEvent e) {
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {

    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {

    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        return false;
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onDoubleTap(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent e) {
        return false;
    }
}

I'm debugging every method, but none get's called. Where i'm wrong?

Answer 1

The GestureDetectorCompat is not called automatically. You have to override onTouchEvent(MotionEvent event) in your Activity, and pass the event to the gesture detector. E.g.

public boolean onTouchEvent(MotionEvent event) {
    return gestureDetectorCompat.onTouchEvent(event);
}

You can find the documentation here. Please refer to it, for the meaning of the returning value.