Tint / dim drawable on touch

Question

The app I\'m currently working on uses a lot of ImageViews as buttons. The graphics on these buttons use the alpha channel to fade out the edges of the button and make them look

Answer 1

I think this solution is simple enough:

    final Drawable drawable = ... ;
    final int darkenValue = 0x3C000000;
    mButton.setOnTouchListener(new OnTouchListener() {
        Rect rect;
        boolean hasColorFilter = false;

        @Override
        public boolean onTouch(final View v, final MotionEvent motionEvent) {
            switch (motionEvent.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    rect = new Rect(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());
                    drawable.setColorFilter(darkenValue, Mode.DARKEN);
                    hasColorFilter = true;
                    break;
                case MotionEvent.ACTION_MOVE:
                    if (rect.contains(v.getLeft() + (int) motionEvent.getX(), v.getTop()
                            + (int) motionEvent.getY())) {
                        if (!hasColorFilter)
                            drawable.setColorFilter(darkenValue, Mode.DARKEN);
                        hasColorFilter = true;
                    } else {
                        drawable.setColorFilter(null);
                        hasColorFilter = false;
                    }
                    break;
                case MotionEvent.ACTION_UP:
                case MotionEvent.ACTION_CANCEL:
                    drawable.setColorFilter(null);
                    hasColorFilter = false;
                    break;
            }
            return false;
        }
    });