Question

How to make a button which when pressed turns green, and after key again to red.

Answer 1

@Override
    public boolean onTouch(final View view, MotionEvent event) {

    final int action = event.getAction();

        if(view.getId()==R.id.yourButton){
            if(action == MotionEvent.ACTION_DOWN)
                  yourButton.setBackgroundResource(R.drawable.ic_button_green);
            if(action == MotionEvent.ACTION_UP)
                  yourButton.setBackgroundResource(R.drawable.ic_button_red);
        }

 }