MonoBehaviour 单例

SingletonMono.cs

using UnityEngine;

/// <summary>
/// extends this class to become singleton class.
/// </summary>
/// <typeparam name="T"> T is a SingletonMono class </typeparam>
public class SingletonMono<T> : MonoBehaviour where T : SingletonMono<T>
{
    private static T _instance;

    public static T Instance
    {
        get
        {
            if (_instance == null)
                _instance = FindObjectOfType<T>();

            if (_instance != null) return _instance;

            var go = new GameObject(typeof(T) + "_Singleton");
            _instance = go.AddComponent<T>();
            DontDestroyOnLoad(go);

            return _instance;
        }
    }

    public static T GetMonoInstance()
    {
        if (_instance == null)
        {
            if (Application.isPlaying)
            {
                var go = new GameObject(typeof(T).Name);
                _instance = go.AddComponent<T>();
                DontDestroyOnLoad(go);
            }
        }

        return _instance;
    }

    protected virtual void Awake()
    {
        if (_instance == null)
            _instance = this as T;
    }

    public virtual void Init()
    {
    }

    public void Free()
    {
        FreeSingleton();
        _instance = null;
        Destroy(gameObject);
    }

    protected virtual void FreeSingleton()
    {
    }
}