GestureDetector not recognizing gestures

Question

For some reason my gesture detector is not working. I have looked at the multiple other answers that say to implement on down. and I have but it still doesnt work. Can anybody help? Here is my code that fails to work. As you can see I iplemented onDown

public class HomeActivity extends FragmentActivity implements 
GestureDetector.OnGestureListener,
GestureDetector.OnDoubleTapListener{
    private static final String DEBUG_TAG = "Gestures";
    GestureDetectorCompat mDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        View contentView = findViewById(R.id.container);
        System.out.println("hi");
        if (savedInstanceState == null) {

            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
        SystemBarTintManager tintManager = new SystemBarTintManager(this);
        tintManager.setStatusBarTintEnabled(true);
        tintManager.setStatusBarTintColor(Color.parseColor("#33000000"));
        mDetector = new GestureDetectorCompat(this,this);
        // Set the gesture detector as the double tap
        // listener.
        mDetector.setOnDoubleTapListener(this);
    }


    @Override
    public boolean onDown(MotionEvent event) { 
        Log.d(DEBUG_TAG,"onDown: " + event.toString()); 
        Toast.makeText(this,"hi", Toast.LENGTH_LONG).show();
        System.out.println("ondown");
        return true;
    }

    @Override
    public boolean onFling(MotionEvent event1, MotionEvent event2, 
            float velocityX, float velocityY) {
        Log.d(DEBUG_TAG, "onFling: " + event1.toString()+event2.toString());
        return true;
    }

    @Override
    public void onLongPress(MotionEvent event) {
        Log.d(DEBUG_TAG, "onLongPress: " + event.toString()); 
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
            float distanceY) {
        Log.d(DEBUG_TAG, "onScroll: " + e1.toString()+e2.toString());
        return true;
    }

    @Override
    public void onShowPress(MotionEvent event) {
        Log.d(DEBUG_TAG, "onShowPress: " + event.toString());
    }

    @Override
    public boolean onSingleTapUp(MotionEvent event) {
        Log.d(DEBUG_TAG, "onSingleTapUp: " + event.toString());
        return true;
    }

    @Override
    public boolean onDoubleTap(MotionEvent event) {
        Log.d(DEBUG_TAG, "onDoubleTap: " + event.toString());
        return true;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent event) {
        Log.d(DEBUG_TAG, "onDoubleTapEvent: " + event.toString());
        return true;
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent event) {
        Log.d(DEBUG_TAG, "onSingleTapConfirmed: " + event.toString());
        return true;
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,
                    false);
            return rootView;
        }
    }


    @Override
    public boolean onTouchEvent(MotionEvent event){ 

        int action = MotionEventCompat.getActionMasked(event);
        switch(action) {
            case (MotionEvent.ACTION_SCROLL) :
            return true;
            default : 
                return super.onTouchEvent(event);
        }   

    }

Answer 1

Put the event handlers inside an extension of the SimpleOnGestureListener. Take a look at the last example here: https://developer.android.com/training/gestures/detector.html

In your code:

mDetector = new GestureDetectorCompat(this,new MyGestureListener());

Where you have MyGestureListener extend the SimpleOnGesture Listener:

class MyGestureListener extends GestureDetector.SimpleOnGestureListener {
        private static final String DEBUG_TAG = "Gestures"; 

        @Override
        public boolean onDown(MotionEvent event) { 
            Log.d(DEBUG_TAG,"onDown: " + event.toString()); 
            return true;
        }

        @Override
        public boolean onFling(MotionEvent event1, MotionEvent event2, 
                float velocityX, float velocityY) {
            Log.d(DEBUG_TAG, "onFling: " + event1.toString()+event2.toString());
            return true;
        }
    }