Unity3D-启动unity事件，切换平台监听

1，启动unity监听，针对unity启动监听，可以做些版本检测，以及平台切换监听，可以做些自己想做的操作

[InitializeOnLoad]，添加这个标示，标示在unity启动的时候会执行这个脚本

unity官方给的解释是：

Running Editor Script Code on Launch

    Sometimes it is useful to be able to run some editor script code in a project as soon as Unity launches without requiring action from the user.
You can do this by applying the InitializeOnLoad attribute to a class which has a static constructor. 
A static constructor is a function with the same name as the class, 
declared static and without a return type or parameters (see here for more information)

using UnityEngine;
using UnityEditor;

[InitializeOnLoad]
public class Startup {
    static Startup()
    {
        Debug.Log("Up and running");
    }
}

2,代码切换平台方法  EditorUserBuildSettings.SwitchActiveBuildTarget(BuildTarget.Android)

监听平台切换后方法 

EditorUserBuildSettings . activeBuildTargetChanged = delegate ( ) {

if ( EditorUserBuildSettings . activeBuildTarget == BuildTarget . Iphone ) {

Debug . Log ( "do you want to do" ) ;

}

} ;