@Override
    public void draw(Canvas canvas) {
        // In this, we check the animation state before call draw
        if (isRealRunning)
            super.draw(canvas);
    }
Called from the drawable's draw() method after the canvas has been set to
draw the shape at (0,0). Subclasses can override for special effects such
as multiple layers, stroking, etc.
caprice/ui/src/main/java/net/qiujuer/genius/ui/drawable/TouchEffectDrawable.java