unity3d Singletons in Unity Implementation using RuntimeInitializeOnLoadMethodAttribute
Example
Since Unity 5.2.5 it's possible to use RuntimeInitializeOnLoadMethodAttribute to execute initialization logic bypassing MonoBehaviour order of execution. It provides a way to create more clean and robust implementation:
using UnityEngine;
sealed class GameDirector : MonoBehaviour
{
// Because of using RuntimeInitializeOnLoadMethod attribute to find/create and
// initialize the instance, this property is accessible and
// usable even in Awake() methods.
public static GameDirector Instance
{
get; private set;
}
// Thanks to the attribute, this method is executed before any other MonoBehaviour
// logic in the game.
[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
static void OnRuntimeMethodLoad()
{
var instance = FindObjectOfType<GameDirector>();
if (instance == null)
instance = new GameObject("Game Director").AddComponent<GameDirector>();
DontDestroyOnLoad(instance);
Instance = instance;
}
// This Awake() will be called immediately after AddComponent() execution
// in the OnRuntimeMethodLoad(). In other words, before any other MonoBehaviour's
// in the scene will begin to initialize.
private void Awake()
{
// Initialize non-MonoBehaviour logic, etc.
Debug.Log("GameDirector.Awake()", this);
}
}
The resulting order of execution:
GameDirector.OnRuntimeMethodLoad()started...GameDirector.Awake()GameDirector.OnRuntimeMethodLoad()completed.OtherMonoBehaviour1.Awake()OtherMonoBehaviour2.Awake(), etc.
