Fling/Swipe Gestures not detected

Question

I am implementing Gesture detection for swipe/fling movements using a inner class SimpleOnGestureListener. However no gestures are detected.

The xml layout has a parent ScrollView so I a wondering if this is a potential cause.

In onCreate I initialise the GestureListener:

public class ViewSelectedDive extends Activity implements OnClickListener,
        OnRatingBarChangeListener {...

public GestureDetectorCompat gestureDetectorObject;

protected void onCreate(Bundle savedInstanceState) {..
// instantiate gesture detector
        gestureDetectorObject = new GestureDetectorCompat(this, new GestureListener());

Override the onTouchEvent method to ensure that the gesture listener is used when a touch events is detected.

@Override
    public boolean onTouchEvent(MotionEvent event) {
        // tell teh activity tto use gerture listener when touch event is detected

        gestureDetectorObject.onTouchEvent(event);

        Log.d(TAG, "312 ON TOUCH EVENT");
        return super.onTouchEvent(event);
    }

// inner class to handle guerter detection

    public class GestureListener extends GestureDetector.SimpleOnGestureListener{

        private float flingMin=100;
        private float velocityMin = 100;



        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                float velocityY) {
            // TODO Auto-generated method stub


            Log.d(TAG, "ON FLING INNER CLASS 951");
            // user move to next dive in db
            boolean moveToNextDive=false;
            boolean moveToPreviousDive=false;

            // caulate the change in x pos within fling ges
            float horizontalDiff = e2.getX()-e1.getX();
            float verticalDiff = e2.getY() - e1.getY();

            // calulate the abs values
            float absHDiff = Math.abs(horizontalDiff);
            float absVDiff = Math.abs(verticalDiff);
            float absVelocityX = Math.abs(velocityX);
            float absVelocityY = Math.abs(velocityY);

                    // now of hor distance > vertival distance , move back or forward
                    if(absHDiff>absVDiff && absHDiff>flingMin && absVelocityX> velocityMin){

                        // swiping forwad
                        if(horizontalDiff>0) {
                            moveToPreviousDive=true;

                            Toast.makeText(getApplicationContext(), "BACKWARD GESTURE DETECTED", Toast.LENGTH_LONG).show();
                            Log.d(TAG, "SWIPE HORIZONTAL DETECTED BACKWARD");

                        }else{
                            moveToNextDive=true;
                                Toast.makeText(getApplicationContext(), "FORWARD GESTURE DETECTED", Toast.LENGTH_LONG).show();
                                Log.d(TAG, "SWIPE HORIZONTAL FORWAD DETECTED BACKWARD");
                        }

                    }// outer ifelse if(absVDiff>flingMin && absVelocityY>velocityMin){

                    else if(absVDiff>flingMin && absVelocityY>velocityMin){

                        // vertical swipe detected

                          if(verticalDiff>0) {
                              moveToPreviousDive=true;

                              Toast.makeText(getApplicationContext(), "VERTICAL BACKWARD GESTURE DETECTED", Toast.LENGTH_LONG).show();
                              Log.d(TAG, "SWIPE VERTICAL DETECTED BACKWARD");
                          }


                          else{
                              moveToNextDive=true;

                              Log.d(TAG, "SWIPE VERTICAL FORWARD DETECTED BACKWARD");
                              Toast.makeText(getApplicationContext(), "VERTICAL FORWARD GESTURE DETECTED", Toast.LENGTH_LONG).show();
                          }
                        }

            return true;
        }

        @Override
        public boolean onDown(MotionEvent e) {

//          Returning true tells the operating system that your code
//          is interested in the remaining gesture events. 
            Log.d(TAG, "ON DOWN INNER CLASS 1010");
            return true;
        }

dancingbush dancingbush · Accepted Answer · 2014-10-08T13:26:23

Got it, the scrollview will register all touch events so you need to dispatch them to Gesture detector object by overriding activities disptachTouchEvent... hope this helps anyone in same situation..

@Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        // must use this to pass event on to Gesture object from scrollvoew n xml

        super.dispatchTouchEvent(ev);

        return this.gestureDetectorObject.onTouchEvent(ev);
    }

Fling/Swipe Gestures not detected

1 Answers