Question

im trying to detect when a user make a left or right swing in the activity.
Currently I’m using a OnGestureListener and the method onFling() and my problem is that I don’t achieve a nice way of detecting it.

I’d like a behaviour similar to the others applications and the “native” Android swing detection but with the code (appended below) I have a lot of wrong swing detections. If someone have already solved that I’d like a tip =)

Thats the code I’m using

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,float velocityY) {
    //Get Position
    float ev1X = e1.getX();
    float ev2X = e2.getX();

    //Get distance of X (e1) to X (e2)
    final float xdistance = Math.abs(ev1X - ev2X);
    //Get velocity of cursor
    final float xvelocity = Math.abs(velocityX);

    if( (xvelocity > SWIPE_MIN_VELOCITY) && (xdistance > SWIPE_MIN_DISTANCE) )
    {
        if(ev1X > ev2X)//Switch Left
        {
            if (Manager.debug) Log.d(Manager.appname,"SWING_LEFT_EVENT");
            moveToRight();
        }
        else//Switch Right
        {
            if (Manager.debug) Log.d(Manager.appname,"SWING_RIGHT_EVENT");
            moveToLeft();
        }
    }

    return false;
}

Answer 1

I am not sure how far this is useful, but this is how I do it.

private static final int SWIPE_MIN_DISTANCE = 120;
private static final int SWIPE_MAX_OFF_PATH = 250;
private static final int SWIPE_THRESHOLD_VELOCITY = 100;
@Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        Log.d("---onFling---", e1.toString() + e2.toString() + "");

        try {
            if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                return false;
            // right to left swipe
            if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
                    && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                //do your code

            } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
                    && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                //left to right flip
                }
            }
        } catch (Exception e) {
            // nothing
        }
        return false;
    }