通过一个WifiAdmin类的实例来说明如何操作Wifi，这是我自己写的一个类，用于对Wifi的操作进行一次封装，里面的方法很多，我们本次Demo只用到了其中几种-Explains how to operate Wifi, which is a class that I wrote it myself, for instance a WifiAdmin class Wifi operation once the package inside the Demo only used a few of