NullReferenceException Object reference not set to an instance of an object

Question

i got thios error message in one of my script, and i can't figure out why it shows that error, anybody who can help?

this is the full error message: NullReferenceException: Object reference not set to an instance of an object followPlayer.Update () (at Assets/Scripts/SeaSerpent/followPlayer.js:14)

and here's the code

 var Target : Transform ;
 
 var maxDistance = 1;
 
 var Speed = 7;
 
 var getStart :flyscript3;
 getStart = GetComponent(flyscript3);
 
 function Update () 
 {
     var dist = Vector3.Distance(Target.position, transform.position);

//line 14 if(getStart.start) {

     if(dist > maxDistance)
         {
         transform.LookAt(Target);
         transform.Translate(Vector3.forward * Speed * Time.smoothDeltaTime);
         }
         else
         {
             if(dist < maxDistance)
             {
                 transform.LookAt(Target);
             }
         }
     }
     else
     {
     
     }
 }

Answer 1

Answer by dannyskim · Dec 03, 2011 at 11:20 PM

Don't believe you can initialize the getStart value outside of a method. What you should try doing is removing that GetComponent line from the variable declarations and adding it into either the Start() or Awake() method, and see what happens.

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Answer 2

Answer by jahroy · Dec 03, 2011 at 07:51 PM

You're getting that error because the variable named getStart is null.

You should try to assign that variable in Start() or Awake().

You should also check if it's null (and print an error message) before you try to use it:

function Start () { getStart = gameObject.GetComponent(flyscript3); }

/ do nothing if getStart is null /

function Update ()
{
    / if getStart is null, print error message and bail! /

 if ( ! getStart ) {
     Debug.LogError("getStart is null!");
     return;
 }

 if ( getStart.start ) {
     /* do stuff */
 }

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Raymond 2 · Dec 04, 2011 at 12:48 AM 0

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I still get the same message, could it be something else?

syclamoth · Dec 04, 2011 at 01:41 AM 0

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No, it really couldn't be. Assu$$anonymous$$g that 'getStart.start' is a boolean, boolean values can never be null (only true or false) and so it can't be that. For the checker, you could try the line

 if(getStart == null)

ins$$anonymous$$d- sometimes the other thing doesn't work as expected (but I can't remember the circumstances under which that happens).

jahroy · Dec 04, 2011 at 04:23 AM 1

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You might also get that error if there isn't a flyscript3 script attached to the object your script is attached to, but you still want to call GetComponent from Start or Awake.

NullReferenceException Object reference not set to an instance of an object

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