Unity Singleton Pattern

Question

Its just a question that bugs me on Unity.

We often use Singleton objects like game managers and so and there are two ways to go for this.

One is to use a Singleton.cs c sharp class as follows:

using System;
using System.Linq;
using UnityEngine;

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
    static T instance;

    DateTime BirthTime;

    public static T Instance
    {
        get
        {
            if (instance == null)
                Initialize();

            return instance;
        }
    }

    private void Awake()
    {
        BirthTime = DateTime.Now;
    }

    public static void Initialize()
    {
        if (instance == null)
            instance = FindObjectOfType<T>();
    }
}

And then derive our GameManager As

GamaManager : Singleton<GameManager>

In popular opinion, this method is CPU consuming, particularly on mobile as Unity has to iterate through hierarchy of so many objects for using the Initialize method mentioned in singleton.

A simpler approach is to create private instance and initialize it in Start or Awake as:

GameManager : MonoBehaviour
{
    public static GameManager Instance { get; private set; }

    void Start()
    {
        Instance = this;
    }
}

But I think, its like writing same code again and again. Can anybody suggest a cleaner approach to this?

Answer 1

I'm not sure what you want exactly, but in singleton pattern I prefer make a main class like GameManager and set it as a singleton class by using this piece of code:

static GameManager _instance;
    public static GameManager instance {
        get {
            if (!_instance) {
                _instance = FindObjectOfType<GameManager>();
            }
            return _instance;
        }
    }

Or the piece of code that you wrote, after that define variables according to other sub managers type and access to them by GameManagersingleton.

For example:

public BulletManager myBulletManager;

and use it like this:

GameManager.instance.myBulletManager.Fire();