NullReferenceException ?? [SOLVED]

Scripting
1

Okay. I am having little problem. When I call a function that is an RPC but I don’t call it over the network. I call it locally, what it should do is disable one canvas, and enable another. It keeps throwing a nullreferenceexception error although BOTH items are assigned in the editor.

Here is script 1 which calls this function

using UnityEngine;

public class Missile : Photon.MonoBehaviour {

    Vector3 properRotation;

    float speed = 1.1f;
    public GameObject target;
    bool shouldGo;
    void Start()
    {
        shouldGo = true;

        if (PhotonNetwork.player.ID == 1001)
        {
            properRotation = new Vector3(transform.rotation.x, -90, transform.rotation.z);
            transform.eulerAngles = new Vector3(properRotation.x, properRotation.y, properRotation.z);
        }
        else
        {
            properRotation = new Vector3(transform.rotation.x, 90, transform.rotation.z);
            transform.eulerAngles = new Vector3(properRotation.x, properRotation.y, properRotation.z);
        }
    }

    void Update () {
        if (shouldGo)
        {
            transform.position = Vector3.MoveTowards(transform.position, target.transform.position, speed * Time.deltaTime);
        }
    }

    void OnCollisionEnter(Collision col)
    {
        if (col.gameObject == target.gameObject)
        {
            PlayerNetworkController network = new PlayerNetworkController();
            network.winGame(); //HERE IS WHERE IT IS CALLED
            shouldGo = false;
            networkView.RPC("hitPlanet", PhotonTargets.Others, null);
        }
    }
}

And here is where the function is

using UnityEngine;

public class PlayerNetworkController : Photon.MonoBehaviour {
    public Canvas Main;
    public Canvas Win;

    void Start(){
    }

    public void lose()
    {
        photonView.RPC("winGame", PhotonTargets.Others, null);
        LeaveRoom();
    }

    public void LeaveRoom()
    {
        PhotonNetwork.LeaveRoom();
    }

    void OnLeftRoom()
    {
        PhotonNetwork.LoadLevel(Application.loadedLevel);
    }

    [PunRPC]
    public void winGame()
    {
        Main.GetComponent<Canvas>().enabled = false;
        Win.GetComponent<Canvas>().enabled = true;
    }

    [PunRPC]
    void hitPlanet()
    {
        PhotonNetwork.LeaveRoom();
    }
}

Any ideas on why this isn’t working? Thanks!

2

Main & win are canvas, can you try Main.enabled=false ?

3

Yes, I have tried this before. It doesn’t work.

4

Well, Main and Win are null, how do you assign them ?

5

In the editor. Both canvases are the child of the prefab the script is attached to that requires them. I have run multiple tests. They are still correctly assigned through out the entire process.

6

Have you try to assign them at runtime with the Start function ?

7

Using GameObject.Find()?

Hmm. I suppose. I’ll give it a shot and see what happens!
E: Nope, it still throws the same error

8

Can you show us the gameObject in question in the hierarchy at runtime ?

9

This is the canvas when the prefab first spawns in

and this is the script when the prefab first spawns in

1915×454 75.9 KB

Note the second players planet object does not effect the problem.

10

You instanciate a new Object : PlayerNetworkController network =new PlayerNetworkController();

So in the network variable, there is not reference to the canvas.

How the gameObject with the script Missile is instantiated ?

11

Hmm possibly. I will take a look at the missile after its instantiated and see whats going on there.

Here is the script that instantiates the missile

using UnityEngine;
using UnityEngine.UI;

public class LaunchRocket : MonoBehaviour {

    public static bool shouldSelectPlanet;
    public GameObject selectedPlanet;
    public Text missileText;
    int check = 0;

    public GameObject myPlanet;

    void Start()
    {
        myPlanet = GameObject.FindGameObjectWithTag("Player");
        missileText = GameObject.Find("LaunchRocketsText").GetComponent<Text>();
    }

    void Update()
    {
        if (myPlanet.GetComponent<PlayerUnits>().missiles >= 1)
        {
            missileText.text = "Launch Rocket - " + myPlanet.GetComponent<PlayerUnits>().missiles.ToString();
            missileText.GetComponentInParent<Button>().interactable = true;
        }
        else
        {
            if (MissileFactory.canCreateRockets)
            {
                missileText.GetComponentInParent<Button>().interactable = true;
                missileText.GetComponent<Text>().text = "Create a rocket";
            }
            else
            {
                missileText.GetComponentInParent<Button>().interactable = false;
                missileText.GetComponent<Text>().text = "Create a missile launch bay!";
            }
        }

      
        if (shouldSelectPlanet == true && Input.GetMouseButtonDown(0))
        {
            Ray ray = Camera.main.GetComponent<Camera>().ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
            if (Physics.Raycast(ray, out hit, Mathf.Infinity))
            {
                if (check == 0)
                {
                    switch (hit.transform.tag)
                    {
                        case "Player":
                            GameManager.news = "You can not destroy your own planet!";
                            break;
                        case "Enemy":
                            selectedPlanet = hit.transform.gameObject;
                            GameManager.news = "Click this planet again to verify you wish to destroy it!";
                            check++;
                            break;
                        default:
                            GameManager.news = "Please select a planet to destroy!";
                            break;
                    }
                }
                else if (check == 1 && hit.transform == selectedPlanet.transform)
                {
                    LaunchRocketAtPlanet();
                    check = 0;
                    shouldSelectPlanet = false;
                }
                else
                {
                    check = 0;
                    GameManager.news = "Please select a planet to destroy!";
                }
            }
        }
      
    }

    public void LaunchRocketAtPlanet()
    {
        GameObject missile = PhotonNetwork.Instantiate("Missile", transform.position, Quaternion.identity, 0) as GameObject; //MISSILE IS CREATED HERE
        missile.GetComponent<Missile>().target = selectedPlanet;
        myPlanet.GetComponent<PlayerUnits>().missiles -= 1;
        GameManager.isLaunchingMissile = false;
    }

    public static void CreateMissile()
    {
        GameObject myPlanet;
        myPlanet = GameObject.FindGameObjectWithTag("Player");
        if (myPlanet.GetComponent<PlanetController>().metal >= 1500 &&
            myPlanet.GetComponent<PlanetController>().water >= 800 &&
            myPlanet.GetComponent<PlanetController>().lightPoints >= 10 &&
            myPlanet.GetComponent<PlayerUnits>().C_missile == 1)
        {
            myPlanet.GetComponent<PlayerUnits>().missiles++;

            myPlanet.GetComponent<PlanetController>().lightPoints -= 10;
            myPlanet.GetComponent<PlanetController>().water -= 800;
            myPlanet.GetComponent<PlanetController>().metal -= 1500;
        }
    }
}
12

You can add a Property to your Missile class :

public class Missile : Photon.MonoBehaviour {
[LIST=1]
    Vector3 properRotation;

   GameObject player;

    float speed = 1.1f;
    public GameObject target;
    bool shouldGo;

[/LIST]
Then when you instanciate your Missile you can add the player who lunch it :

  public void LaunchRocketAtPlanet()
    {
        GameObject missile = PhotonNetwork.Instantiate("Missile", transform.position, Quaternion.identity, 0) as GameObject; //MISSILE IS CREATED HERE
        missile.GetComponent<Missile>().target = selectedPlanet;
      
missile.GetComponent<Missile>().player = myPlanet;
myPlanet.GetComponent<PlayerUnits>().missiles -= 1;
        GameManager.isLaunchingMissile = false;
    }

Then

 void OnCollisionEnter(Collision col)
    {
        if (col.gameObject == target.gameObject)
        {
            PlayerNetworkController network = this.player.GetComponent<PlayerNetworkController>();
            network.winGame(); //HERE IS WHERE IT IS CALLED
            shouldGo = false;
            networkView.RPC("hitPlanet", PhotonTargets.Others, null);
        }
    }
13

Yep, this is exactly what I did after reading your last post saying it creates a new script of that type therefore leaving both canvases un referenced.

thank you very much :slight_smile:

14

You are welcome !