在unity中有兩種單例型別，一種是普通單例，即普通c#類，另一種是繼承了MonoBehaviour的單例。

普通單例：

public abstract class CSharpSingletion<T> where T : new() {  

    private static T instance;  
    public static T Instance  
    {  
        get  
        {  
            if (instance == null)  
            {  
                instance = new
 
 T();  
            }  
            return instance;  
        }  
    }  

} 

繼承了MonoBehaviour的單例：

using UnityEngine;  
using System.Collections;  

public abstract class MonoSingletion<T> : MonoBehaviour where T : MonoBehaviour {  

    private static string rootName = "MonoSingletionRoot"
 
;  
    private static GameObject monoSingletionRoot;  

    private static T instance;  
    public static T Instance  
    {  
        get  
        {  
            if (monoSingletionRoot == null)  
            {  
                monoSingletionRoot = GameObject.Find(rootName);  
                if
 
 (monoSingletionRoot == null) Debug.Log("please create a gameobject named " + rootName);  
            }  
            if (instance == null)  
            {  
                instance = monoSingletionRoot.GetComponent<T>();  
                if (instance == null) instance = monoSingletionRoot.AddComponent<T>();  
            }  
            return instance;  
        }  
    }  

}  

第二種需要在場景中建立一個名為MonoSingletionRoot的空物體，才能使用。