68 lines
2.0 KiB
C#
68 lines
2.0 KiB
C#
using UnityEngine;
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public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
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{
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private static T _instance;
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private static object _lock = new object();
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public static T Instance
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{
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get
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{
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if (applicationIsQuitting) {
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Debug.LogWarning("[Singleton] Instance '"+ typeof(T) +
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"' already destroyed on application quit." +
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" Won't create again - returning null.");
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return null;
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}
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lock(_lock)
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{
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if (_instance == null)
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{
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_instance = Object.FindFirstObjectByType<T>();
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if ( Object.FindObjectsByType<T>(FindObjectsInactive.Exclude, FindObjectsSortMode.None).Length > 1 )
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{
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Debug.LogError("[Singleton] Something went really wrong " +
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" - there should never be more than 1 singleton!" +
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" Reopenning the scene might fix it.");
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return _instance;
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}
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if (_instance == null)
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{
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GameObject singleton = new GameObject();
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_instance = singleton.AddComponent<T>();
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singleton.name = typeof(T).ToString() + " (Singleton)";
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DontDestroyOnLoad(singleton);
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Debug.Log("[Singleton] An instance of " + typeof(T) +
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" is needed in the scene, so '" + singleton +
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"' was created with DontDestroyOnLoad.");
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} else {
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Debug.Log("[Singleton] Using instance already created: " +
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_instance.gameObject.name);
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}
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}
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return _instance;
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}
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}
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}
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private static bool applicationIsQuitting = false;
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/// <summary>
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/// When Unity quits, it destroys objects in a random order.
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/// In principle, a Singleton is only destroyed when application quits.
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/// If any script calls Instance after it have been destroyed,
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/// it will create a buggy ghost object that will stay on the Editor scene
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/// even after stopping playing the Application. Really bad!
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/// So, this was made to be sure we're not creating that buggy ghost object.
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/// </summary>
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public void OnDestroy () {
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applicationIsQuitting = true;
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}
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} |