Cannot access class variable in member function

Question

In Unity C# script I have a singleton game controller object in which the game variables are stored but I am getting odd behaviour when accessing them in a member function. It prints the initialized value, not the current one. In the update function however it prints the correct value each frame. I summarized the class below. The controller class has a static reference to itself. If you need to know additional details you can ask. I am new to C# and Unity so I might be lacking some obvious answer.

Thanks

public class controller : MonoBehaviour {

    public int[] star = new int[64];

    void Start(){ /* calls another function to set 0 for each star index */ }

    void Update(){  // during gameplay star[0] gets a value of 1
        print(star[0]);  // prints correct value which is 1
    }

    public void checkValue(){
        print(star[0]); // prints 0 incorrectly which should be 1     
    }


}

Answer 1

I've set up a little example. I created a button and an empty gameobject GameController. I added this code to the GameController:

using UnityEngine;
using System.Collections;

public class GameController : MonoBehaviour {

    public static GameController instance;

    [System.NonSerialized] public int[] star = new int[64];

    private void Awake()
    {
        if(instance == null)
            instance = this;
        else if(instance != this)
            Destroy(gameObject);

        DontDestroyOnLoad(gameObject);
    }

    private void Start()
    {
        StartCoroutine(SetAllTo(1));
    }

    // for simulating some changes during the game
    private IEnumerator SetAllTo(int value)
    {
        yield return new WaitForSeconds(2.0f);

        for(int i = 0; i < star.Length; i++)
            star[i] = value;

        Debug.Log("Setting done");
    }

    public void PrintFirst()
    {
        Debug.Log(star[0]);
    }
}

Now I added an OnClick event to the button, dragged the GameController gameobject into the slot and picked PrintFirst.

I start the game and click the button once before the Coroutine log and once after and the console gives the following:

0
Setting Done
1

Edit:
The gameobject for the OnClick event must be in the scene, it can't be a prefab in the assets folder.

Answer 2

It seems that's the call to the start function may also occurs in your external calls before the call for ckeckValue

Try debugging by putting breakpoint in each of these functions and you can understand what is going on.

Answer 3

The start function runs once in the beginning of the game and not again.

For that you have pattern - Singleton

The second thing why to call external function to initialize class member? do it in your default contractor.

- C# default constractor already initialize 0 in int[].

if you still what to run Start from other scope in your code make it public (c# makes variable/methods as private by default)