How to make a "swipe up" function like in many custom launchers?

Question

I'm doing my own custom launcher for Android at the moment. Everything works so far. But there is one point where I need help. I would like to do something like a swipe up on the home screen to display all installed apps. Therefore I do not want to start a new activity, cause of the delay. Maybe it's possible to change the layout file with something like an animation when a gesture is detected? And how would I detect the swipe?

Answer 1

It's really easy to detect motion:

someViewLikeLinearLayout.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    //put finger on screen
                    return true;
                case MotionEvent.ACTION_UP:
                    //release the finger
                    return true;

            }

        }
    });

Just switch event and you can get many actions via MotionEvent Good luck!