NullReference

Questions & Answers
1

I have gotten a null reference exception on line 10

   using UnityEngine;
    using System.Collections;
    
    public class MainMenu : MonoBehaviour {
    public int ServerPort = 25565;
    public int MaxiPlayers = 27;
    
    void OnGUI(){
    if(GUI.Button(new Rect(Screen.width/2-310,Screen.height/2-175,183,28),"StartServer")){
    NetworkManager2.Instance.StartServer(MaxiPlayers,ServerPort);
    }
    }
  }

And on the script NetworkManager2

using UnityEngine;
using System.Collections;

public class NetworkManager2 : MonoBehaviour {
	public static NetworkManager2 Instance;

	// Use this for initialization
	void Start () {
		Instance = this;
	}
	public void StartServer(int MaxPlayers, int Port){
		Debug.Log ("Good");
	}
}

I don’t know why I get the error! I heard that you can ignore it but then it does not do the void (It does not do what is in StartServer!).

2

you should check that NetworkManager2.Instance isn’t null before you try to do anything with it.

instead of this:

if(GUI.Button(new Rect(Screen.width/2-310,Screen.height/2-175,183,28),"StartServer"))
{
    NetworkManager2.Instance.StartServer(MaxiPlayers,ServerPort);
}

try this

if (NetworkManager2.Instance != null)
{
    if(GUI.Button(new Rect(Screen.width/2-310,Screen.height/2-175,183,28),"StartServer"))
    {
        NetworkManager2.Instance.StartServer(MaxiPlayers,ServerPort);
    }
}

you might also try setting Instance in the Awake() function instead of Start()