@Override
    protected synchronized void onDraw(Canvas canvas) {

        final TouchEffectDrawable d = mTouchDrawable;
        if (d != null) {
            d.draw(canvas);
        }

        super.onDraw(canvas);
    }
Update the background color of the circle image view.

@param colorRes Id of a color resource.
caprice/ui/src/main/java/net/qiujuer/genius/ui/widget/FloatActionButton.java