项目中的单例如何管理

在项目中，我们往往会使用到单例，当想清理一下单例了，该怎么做呢？本篇文章提供一个单例管理思路。

将项目中的单例分为两大类，一类是可以被清理的，一类是不可以被清理。定义两个单例的基类，项目中用到的单例，根据需求从这两个基类中选择性的派生。再另外定义一个类，类中定义两个字典，分别存放两种单例的所有实例，当需要实例的时候，分别从对应的字典中去取。对于可被清理的单例，通过 event 链去清理，这样看着要比遍历容器去清理要清爽的多。下面直接上代码。

不可被清理的单例基类:

 1 public class ManagerSingleton<T> where T : class, new()
 2 {
 3     private static T _instance;
 4 
 5     public static T Instance
 6     {
 7         get
 8         {
 9             if (null == _instance)
10             {
11                 _instance = ApplicationManager.GetSingleton(typeof(T).FullName) as T;
12             }
13             return _instance;
14         }
15     }
16 }

可被清理的单例基类:

 1 public class ReleaseSingleton<T> where T : class, new()
 2 {
 3     private static T _instance;
 4 
 5     public static T Instance
 6     {
 7         get
 8         {
 9             if (null == _instance)
10             {
11                 _instance = ApplicationManager.GetReleaseSingleton(typeof(T).FullName) as T;
12                 ApplicationManager.eventReleaseSingleton -= Release;
13                 ApplicationManager.eventReleaseSingleton += Release;
14             }
15             return _instance;
16         }
17     }
18 
19     static void Release()
20     {
21         _instance = null;
22     }
23 }

单例管理类:

 1 using System;
 2 using System.Collections.Generic;
 3 using UnityEngine;
 4 
 5 public class ApplicationManager
 6 {
 7     static private Dictionary<string, object> dictSingleton = new Dictionary<string, object>();         //存放所有 不可被 清理的单例
 8     static private Dictionary<string, object> dictSingletonRelease = new Dictionary<string, object>();  //存放所有 可以被 清理的单例
 9 
10     #region 不可被清理单例
11     public static object GetSingleton(string singletonType)
12     {
13         object singleton;
14 
15         if (!dictSingleton.TryGetValue(singletonType, out singleton))
16         {
17             singleton = Activator.CreateInstance(Type.GetType(singletonType));
18             dictSingleton.Add(singletonType, singleton);
19         }
20 
21         return singleton;
22     }
23 
24     public static void RemoveSingleton(string singletonType)
25     {
26         if (dictSingleton.ContainsKey(singletonType))
27         {
28             dictSingleton.Remove(singletonType);
29         }
30     }
31     #endregion
32 
33     #region 可以被清理单例
34     public static object GetReleaseSingleton(string singletonType)
35     {
36         Debug.Log(singletonType);
37         object singleton;
38         if (!dictSingletonRelease.TryGetValue(singletonType, out singleton))
39         {
40             singleton = Activator.CreateInstance(Type.GetType(singletonType));
41             dictSingletonRelease.Add(singletonType, singleton);
42         }
43 
44         return singleton;
45     }
46 
47     public static void RemoveReleaseSingleton(string singletonType)
48     {
49         if (dictSingletonRelease.ContainsKey(singletonType))
50         {
51             dictSingletonRelease.Remove(singletonType);
52         }
53     }
54     #endregion
55 
56     #region 单例清理
57 
58     public delegate void DeleReleaseSingleton();
59     public static event DeleReleaseSingleton eventReleaseSingleton;
60 
61     public static void ReleaseAllSingleton()
62     {
63         if (null != eventReleaseSingleton)
64         {
65             eventReleaseSingleton();
66             eventReleaseSingleton = null;
67         }
68         dictSingletonRelease.Clear();
69 
70         GC.Collect();
71         GC.WaitForPendingFinalizers(); //挂起当前线程，直到处理终结器队列的线程清空该队列为止。
72     }
73 
74     #endregion
75 }

当需要清理的时候，调用管理类中的方法即可。