MonoBehaviour单例的另外一种省事的写法

 using UnityEngine;

 public class CommSystem: SingletonGeneric<CommSystem>
 {
     public static string version = "v1.0";
     private static CommSystemStub stub = (new GameObject("CommSystemStub")).AddComponent<CommSystemStub>();
 }

 public sealed class CommSystemStub : MonoBehaviour
 {
     private void Awake()
     {
         DontDestroyOnLoad(gameObject);
     }

     private void Start()
     {

     }

     private void Update()
     {

     }

     private void OnDestroy()
     {

     }
 }

CommSystem是普通的Class

 public class SingletonGeneric<T> where T: class, new()
 {
     static private T _instance;
     static private readonly object th_safe = new object();
     static public T Instance
     {
         get
         {
             if (_instance == null)
             {
                 lock (th_safe)
                 {
                     if (_instance == null)
                         _instance = new T();
                 }
             }
             return _instance;
         }
     }
 }

下面的改写让泛型单例支持使用Private的构造函数，这样做更严谨:

 using System;

 public class SingletonGeneric<T> where T: class
 {
     static private T _instance;
     static private readonly object th_safe = new object();
     static public T Instance
     {
         get
         {
             if (_instance == null)
             {
                 lock (th_safe)
                 {
                     if (_instance == null)
                         //_instance = new T();
                         _instance = (T) Activator.CreateInstance(typeof(T), true);
                 }
             }
             return _instance;
         }
     }
 }