"Object reference not set to an instance of an object" problem

Questions & Answers
1

Hello. I am fixing my code. I want it to be more optimised and not to be attached to gameObjects.
I am getting an error : “Object reference not set to an instance of an object”. I know what this problem means, but I do not know how to fix it. How can I receive my GameObjects from the place where I store them?

The place where problem occurs:

public void create () 
{
    //The problem***
	Digger = GameObject.Instantiate (Storage._Digger) as GameObject; //***
}

private _Storage          Storage; //See below
private GameObject		Digger;

The _Storage class, where GameObjects are attatched to:

public class _Storage : MonoBehaviour 
{
	public GameObject _Digger;
}

And the Main class, where Start() and Update() functions are done:

public class _Main : MonoBehaviour 
{	
	void Start () 
	{
		MainDigger.start ();
	}

	void Update () 
	{
		MainDigger.update ();
	}

	private DiggerMovement MainDigger = new DiggerMovement();
}

NullReferenceException: Object reference not set to an instance of an object
DiggerMovement.start () (at Assets/Scritps/DiggerMovement.cs:9)
_Main.Start () (at Assets/Scritps/_Main.cs:9)"

Thanks

2

Sorry for double post, but I solved this problem with little help and want to share the result, if someone will have the same issue in the future. I don’t know if anyone will find this helpful, but anyways… sharing is caring. Also, if someone has any advice, it would be appreciated.

My storage class:

public class _Storage : MonoBehaviour 
{
	public GameObject _Digger;
}

My object class (the same where the problem was):

public class DiggerMovement
{

	public void SetStorage(_Storage s)
	{
		Storage = s;
	}

	public void start () 
	{
		Digger = GameObject.Instantiate (Storage._Digger) as GameObject;
	}

	public void update()
	{}

    private _Storage		Storage;
    private GameObject		Digger;									
}

My main class (where all the actions are done):

public class _Main : MonoBehaviour 
{	
	void Start () 
	{
		_Storage s = GameObject.Find ("Storage").GetComponent<_Storage> ();
		MainDigger.SetStorage (s);
		MainDigger.start ();
	}

	void Update () 
	{
		MainDigger.update ();
	}

	private DiggerMovement MainDigger = new DiggerMovement();
}