仿照别的应用（360Root）的特效做的，从一个圆圈周围，向外扩散水波纹。可以设置扩散的速度，可以设置水波纹的颜色等等。 用来学习自定义的小Demo。
odelled on other applications (360Root) special effects, from a circle around the outward diffusion of water. You can set the speed of diffusion, you can set the color of water, and so on. Small Demo to learn to customize.
