Hey guys, just updated to 5.1 and I’m getting errors such as
and
The latter of the two being a real deal-breaker for singletons. I’ve been using this particular class for over 5 years now and I’d really not like to have to remove it!
Does anyone have a work-around or tips? Maybe I’m just missing something simple?
For good measure, here’s my (now busted) singleton class. It’s a common one with a few tweaks I’ve added over the years…
using UnityEngine;
namespace com.pixelfat.unity.utility
{
/// <summary>
/// Be aware this will not prevent a non singleton constructor
/// such as `T myT = new T();`
/// To prevent that, add `protected T () {}` to your singleton class.
///
/// As a note, this is made as MonoBehaviour because we need Coroutines.
/// </summary>
public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
private static T _instance;
private static object _lock = new object();
protected Singleton () {}
public static T Instance
{
get
{
if (applicationIsQuitting)
{
if(_instance == null)
Debug.LogWarning("[Singleton] Instance '"+ typeof(T) +
"' already destroyed on application quit." +
" Won't create again - returning null.");
return _instance;
}
lock(_lock)
{
if (_instance == null)
{
_instance = (T) FindObjectOfType(typeof(T));
if ( FindObjectsOfType(typeof(T)).Length > 1 )
{
Debug.LogError("[Singleton] Something went really wrong " +
" - there should never be more than 1 singleton!" +
" Reopenning the scene might fix it.");
return _instance;
}
if (_instance == null)
{
GameObject singleton = new GameObject();
_instance = singleton.AddComponent<T>();
singleton.name = "(singleton) "+ typeof(T).ToString();
Singleton<T> _s = _instance as Singleton<T>;
_s.Init();
DontDestroyOnLoad(singleton);
Debug.Log("[Singleton] An instance of " + typeof(T) +
" is needed in the scene, so '" + singleton +
"' was created with DontDestroyOnLoad.");
} else {
Debug.Log("[Singleton] Using instance already created: " +
_instance.gameObject.name);
}
}
return _instance;
}
}
}
private static bool applicationIsQuitting = false;
/// <summary>
/// When Unity quits, it destroys objects in a random order.
/// In principle, a Singleton is only destroyed when application quits.
/// If any script calls Instance after it have been destroyed,
/// it will create a buggy ghost object that will stay on the Editor scene
/// even after stopping playing the Application. Really bad!
/// So, this was made to be sure we're not creating that buggy ghost object.
/// </summary>
public void OnDestroy () {
applicationIsQuitting = true;
}
protected virtual void Init() {;}
}
}