Singleton<T>

gistfile1.txt

using System;

namespace com.qingyi
{
    public class Singleton<T>
    where T : class, new()
    {
        private static T mUniqueInstance;

        public static bool Exists
        {
            get
            {
                return Singleton<T>.mUniqueInstance != null;
            }
        }

        public static T Instance
        {
            get
            {
                if (Singleton<T>.mUniqueInstance == null)
                {
                    Singleton<T>.mUniqueInstance = Activator.CreateInstance<T>();
                }
                return Singleton<T>.mUniqueInstance;
            }
            set
            {
                Singleton<T>.mUniqueInstance = value;
            }
        }

        static Singleton()
        {
        }

        public Singleton()
        {
            if (Singleton<T>.mUniqueInstance != null)
            {
                throw new InvalidOperationException(string.Concat("Singleton [", typeof(T), "] cannot be manually instantiated."));
            }
        }

        public static T Instances()
        {
            if (Singleton<T>.mUniqueInstance == null)
            {
                Singleton<T>.mUniqueInstance = Activator.CreateInstance<T>();
                if (Singleton<T>.mUniqueInstance == null)
                {
                }
            }
            return Singleton<T>.mUniqueInstance;
        }

        public static void Release()
        {
            if (Singleton<T>.Instance != null)
            {
                Singleton<T>.Instance = default(T);
            }
        }
    }
    
    
     public class SingletonMonoBehaviour<T> : MonoBehaviour
    where T : SingletonMonoBehaviour<T>
    {
        private static SingletonMonoBehaviour<T> uniqueInstance;

        public static bool Exists
        {
            get;
            private set;
        }

        public static T Instance
        {
            get
            {
                return (T)SingletonMonoBehaviour<T>.uniqueInstance;
            }
        }

        public SingletonMonoBehaviour()
        {
        }

        protected virtual void Awake()
        {
            if (SingletonMonoBehaviour<T>.uniqueInstance == null)
            {
                SingletonMonoBehaviour<T>.uniqueInstance = this;
                SingletonMonoBehaviour<T>.Exists = true;
            }
            else if (SingletonMonoBehaviour<T>.uniqueInstance != this)
            {
                throw new InvalidOperationException(string.Concat("Cannot have two instances of a SingletonMonoBehaviour : ", typeof(T).ToString(), "."));
            }
        }

        protected virtual void OnDestroy()
        {
            if (SingletonMonoBehaviour<T>.uniqueInstance == this)
            {
                SingletonMonoBehaviour<T>.Exists = false;
                SingletonMonoBehaviour<T>.uniqueInstance = null;
            }
        }
    }
}