移动层加层排序（自己看了很多相似的代码，经过反复的修改和精简总结出来的代码，DVI层可以任意移动，点击不同的层带层切换功能。而且扩展性好。）-Read a lot like their own code, after repeated changes and streamline summed up the code, DVI layer can move, click on the different layers with layer switching. And good scalability.