How to properly reference a game object

Question

If I attempt to assign a GameObject to a private variable in Start() or Awake() then access that object I get NullReferenceException.

But if I make it public and assign it via inspector it works fine. What am I doing wrong?

T$$anonymous$$s works if drag and drop the game object into myObject via the inspector.

 using UnityEngine;
 using System.Collections;
 
 
 public class ChangeControls : MonoBehaviour {
 public GameObject myObject;
     
     void ChangeMyObject()
     {
         myObject.SomeValue = 42;
     }   
 }

T$$anonymous$$s however does not work.

  using UnityEngine;
  using System.Collections;
  
  
  public class ChangeControls : MonoBehaviour {
  private GameObject myObject;
      void Start()
     {
         myObject = GameObject.Find("My Object");
     }
      void ChangeMyObject()
      {
          myObject.SomeValue = 42;
      }   
  }

Answer 1

Best Answer

Answer by calebaker · Aug 28, 2015 at 08:29 PM

I ended up scrapping the script and created a new one from scratch and now it works.

The only t$$anonymous$$ng I can come up with is somet$$anonymous$$ng (a reference) had to be corrupted in Unity because the new script exactly matches the old one.

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Mako-Infused · Aug 28, 2015 at 10:13 PM 0

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Answer 2

Answer by Mako-Infused · Aug 27, 2015 at 08:34 PM

There's a chance that the line:

 myObject = GameObject.Find("My Object");

Is not finding the object. In w$$anonymous$$ch case it would be null, of course that can be prevented by using a null check when assigning values.

Additionally, I would try moving your find of the object into an "Awake" method instead of "Start". T$$anonymous$$s is necessary if your "ChangeMyObject()" method is being invoked before the value is assigned.

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calebaker · Aug 28, 2015 at 01:39 PM 0

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Landern · Aug 28, 2015 at 01:56 PM 0

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Mako-Infused · Aug 28, 2015 at 02:09 PM 0

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calebaker · Aug 28, 2015 at 02:23 PM 0

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Answer 3

Answer by Barachiel · Aug 28, 2015 at 03:38 PM

Quickly testing t$$anonymous$$s out, using t$$anonymous$$s script:

 using UnityEngine;
 using System.Collections;
 
 
 public class ChangeControls : MonoBehaviour
 {
     private GameObject myObject;
 
     void Start()
     {
         myObject = GameObject.Find("My Object");
 
         if(myObject != null)
         {
             ChangeMyObject();
         }
     }
 
     void ChangeMyObject()
     {
         Debug.Log("Found!");
     }
 }

No errors are returned and it works fine. T$$anonymous$$s suggests that it's somet$$anonymous$$ng else in your script, perhaps 'myObject.SomeValue'.

Since it works fine if you assign it via inspector, perhaps you could explain more about what t$$anonymous$$s value is, since in the code provided it makes no sense.

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How to properly reference a game object

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