Ignore null reference?

Unity Engine
1

Is there a way around my problem? I’m using this script to draw out an arrow to where the player is aiming and I get an error that says “NullReferenceException: Object reference not set to an instance of an object”, “GetPlayerPos.Update () (at Assets/Scripts/GetPlayerPos.cs:13)”.
Basically, when one of the players is dead the script can’t find “PlayerOne” because the gameobject is destroyed.

using UnityEngine;
using System.Collections;

public class GetPlayerPos : MonoBehaviour
{
    public string Whatplayer;
    Vector3 PlayerPos = Vector3.zero;
   
    // Update is called once per frame
    void Update ()
    {
        GameObject thePlayer = GameObject.Find(Whatplayer);
        Movement playerScript = thePlayer.GetComponent<Movement>();
        if (!playerScript.dead)
        {
            PlayerPos.x = playerScript.transform.position.x + playerScript.chargeX / 10;
            PlayerPos.y = playerScript.transform.position.y + playerScript.chargeY / 10;
            PlayerPos.z = playerScript.transform.position.z;    

            transform.position = PlayerPos;
        }
    }
}
2

Don’t ignore errors. Handle them.

simplest technical fix to do that would be to add

if(thePlayer)
{

between lines 12 and 13 (with closing } somewhere below obviously).

Or you can address your game logic such that it doesn’t try to find the position of something that is destroyed…

3

Oh hey, you tried to help me last time :stuck_out_tongue:
What you suggested didn’t work for me, I’m probably doing it wrong. I’ve tried so many things and nothing seems to do the trick for me

4

I did this:

void Update ()
    {
        GameObject thePlayer = GameObject.Find(Whatplayer);
        Movement playerScript = thePlayer.GetComponent<Movement> ();

        if (playerScript == null)
        {
            Debug.Log ("Its dead");
        }
        else
        {
            PlayerPos.x = playerScript.transform.position.x + playerScript.chargeX / 10;
            PlayerPos.y = playerScript.transform.position.y + playerScript.chargeY / 10;
            PlayerPos.z = playerScript.transform.position.z;    
            transform.position = PlayerPos;
        }
    }

I’m not getting errors anymore, it just spams my console with “Its dead”

5

The Movement script you are looking for does not exist on thePlayer, hence playerScript is null. Have you forgotten to add it? Have you previously destroyed it? Or are you looking in the wrong place?

1 Like
6

doh, tracked across to the wrong line from the line number… principle still holds. If you “find” or “getcomponent” you can check if it returned something or null before attempting to use it.

Alternatively you can use “requireComponent” attribute to force it to be on the gameobect
http://docs.unity3d.com/ScriptReference/RequireComponent.html

yeah I try… on a good day sometimes I succeed :slight_smile:
(today is apparently not a good day :frowning: :eyes: )

7

The movement script is on the player but when that player dies the player gets destroyed thats why. I want to “kill” the player without it being a problem for the script.

8

Then you either have to reassign the new player when you spawn it to the GetPlayerPos, or look for a new one.
I’d suggest looking for tags rather than looking for gameobject names.

using UnityEngine;
using System.Collections;

public class GetPlayerPos : MonoBehaviour
{
    public string whatplayer;
    Vector3 playerPos = Vector3.zero;
   
    private Movement playerScript;

    void Update ()
    {
        // Make sure playerScript exists.
        if (playerScript)
        {
            if (!playerScript.dead)
            {
                playerPos.x = playerScript.transform.position.x + playerScript.chargeX / 10f;
                playerPos.y = playerScript.transform.position.y + playerScript.chargeY / 10f;
                playerPos.z = playerScript.transform.position.z;    
     
                transform.position = playerPos;
            }
        }
        else
        {
            // No playerScript, look for another.
            GameObject thePlayer = GameObject.Find(whatplayer); // Should probably replace with FindWithTag
            if (thePlayer) // We found the player we're looking for, can we find its Movement component?
            {
                playerScript = thePlayer.GetComponent<Movement>();            
            }
        }
    }
}