Question

I’m using my own GestureDetector class to detect a left|right onFling event. Everything I see looks good in my code but nothing happens…?

I need the added functionality beyond my toggle button that opens|closes a navigation view in my fragments. The toggle calls on a method in my AnimationLayout class as follows:

public void toggleSidebar()
{
if (mContent.getAnimation() != null)
{
return;
}

if (mOpened)
{
/* opened, make close animation */
mAnimation = new TranslateAnimation(0, -mSidebarWidth, 0, 0);
mAnimation.setAnimationListener(mCloseListener);
} else
{
/* not opened, make open animation */
mAnimation = new TranslateAnimation(0, mSidebarWidth, 0, 0);
mAnimation.setAnimationListener(mOpenListener);
}
mAnimation.setDuration(DURATION);
mAnimation.setFillAfter(true);
mAnimation.setFillEnabled(true);
mContent.startAnimation(mAnimation);
}

and…

public void openSidebar()
    {
    if (!mOpened)
    {
    toggleSidebar();
    }
    }

    public void closeSidebar()
    {
    if (mOpened)
    {
    toggleSidebar();
    }
    }

Within my Main Activity the onFling() calls on the toggle sub:

public static AnimationLayout mLayout;

    // these constants are used for onFling
    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_MAX_OFF_PATH = 250;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;
    private GestureDetector gestureDetector;

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mLayout = (AnimationLayout) findViewById(R.id.animation_layout);
        gestureDetector = new GestureDetector(this.getApplicationContext(), new MyGestureDetector());
        // Set the touch listener for the main view to be our custom gesture
        // listener
        mLayout.setOnTouchListener(new View.OnTouchListener() {
            public boolean onTouch(View v, MotionEvent event) {
                if (gestureDetector.onTouchEvent(event)) {
                    return true;
                }
                return false;
            }
        });
    }
      class MyGestureDetector extends SimpleOnGestureListener {
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {

            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) {
                Toast.makeText(getApplicationContext(), "right_left", Toast.LENGTH_LONG).show();
                Log.i("MyGestureDetector", "R2L!");
                mLayout.closeSidebar();
                // left to right swipe
            } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                Toast.makeText(getApplicationContext(), "left_right", Toast.LENGTH_LONG).show();
                Log.i("MyGestureDetector", "L2R!");
                mLayout.openSidebar();
            }

            return false;
        }

        // Return true from onDown for the onFling event to register
        @Override
        public boolean onDown(MotionEvent e) {
            return true;
        }
    }

This Button works fine:

...
case R.id.navToggleBtn : {
                mLayout.toggleSidebar();
            }
...

Answer 1

I give credit to @Devunwired as he suggested above:

If layout contains children that are also touchable, they may be
stealing the events from their parent (your layout).

So I added:

View swipeView = (View) findViewById(R.id.animation_layout_content);
swipeView .setOnTouchListener(new View.OnTouchListener() {...});

Which works wonderfully now.