Object reference not set without object? Calling ListMatches and getting this error

Questions & Answers
1

NullReferenceException: Object reference not set to an instance of an object
NetWorkingServer.OnGUI () (at Assets/Scripts/General/Networking/NetWorkingServer.cs:40)

It is a basic lobby/hud setup i am trying and I am getting this error when I press the button to search for games/ListMatches. I should be getting the ‘no matches found messages’ instead i get this error which i am super confused about, probably something simple i am missing here. edit: the public objects have been set in the inspector so its not that.

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Networking;
using UnityEngine.Networking.Match;
using UnityEngine.Networking.Types;
using System.Collections.Generic;

public class NetWorkingServer : MonoBehaviour{

	public GameObject Menu;
	public Text hostList;
	public string gameName;
	public NetworkManager networkManager;

	//Usethisforinitialization
	void Start(){
		gameName = "game1";
		Menu.SetActive (false);
		networkManager = GetComponent<NetworkManager> ();
	}

	//Updateiscalledonceperframe
	void Update(){



	}
	void OnGUI()
	{

		//gameplay related


		//server related
			if(GUI.Button(new Rect(100,100,250,100),"StartServer")){
				HostServer(gameName);
			}
			if(GUI.Button(new Rect(100,250,250,100),"Find Game/Hosts")){
			
			networkManager.matchMaker.ListMatches (0, 10, "game1", true, 0, 0, networkManager.OnMatchList);

			if (networkManager.matches.Count !=0) {
				Debug.Log ("A list of matches was found");
				foreach (MatchInfoSnapshot match in networkManager.matches) {
					hostList.text = match.name.ToString () + System.Environment.NewLine;
				}
			} else {
				hostList.text = "No matches found";
				Debug.Log ("No matches in requested room!");
			}
			}

		
	}

	public void HostServer(string matchName){

		networkManager.StartMatchMaker ();
		networkManager.matchMaker.CreateMatch (matchName, 4, true, "", "", "", 0, 0,networkManager.OnMatchCreate);

	}
2

After Calling this Methode

networkManager.matchMaker.ListMatches (0, 10, “game1”, true, 0, 0, networkManager.OnMatchList);

You probably need to wait for the callback here. And put the following code… In the callback method.

if (networkManager.matches.Count !=0) {
Debug.Log (“A list of matches was found”);
foreach (MatchInfoSnapshot match in networkManager.matches) {
hostList.text = match.name.ToString () + System.Environment.NewLine;
}
} else {
hostList.text = “No matches found”;
Debug.Log (“No matches in requested room!”);
}
}

3

@nasir_41 how would i go about waiting for the callback? i was under the assumption that NetworkManager.OnMatchList would automatically do that.