NullReferenceException, can't figure out why...

Questions & Answers
1

I have script where instance of class created. This class call function from different class. Well here is code:
Script A:

var antWorker:AntWorker; 
function Start(){
antWorker = new AntWorker(gameObject);
}
function Update() {
antWorker.patrolMove(movePoints*);*

}
class AntWorker:
class AntWorker{

var currentObject:GameObject;
var patrolSpeed:int = 20;
var gravity:int = 20;
var botAction:botActions;

*public function AntWorker(currentObject:GameObject){ *
this.currentObject = currentObject;
botAction = new botActions();
}

  • function patrolMove(target:Vector3){*
  •  botAction.simMove(currentObject,target,patrolSpeed,gravity);*
  • }*

}
Class botActions:
class botActions{
function simMove(currentObject:GameObject,mytarget:Vector3,speed:int,gravity:int){

  • var currentSpeed:int = speed;*

  • var currentGravity:int = gravity;*

  • var currentPos = currentObject.transform.position;*

  • var currentRot = currentObject.transform.rotation;*

  • var controller : CharacterController = currentObject.GetComponent(CharacterController);*

  • if (controller.isGrounded) {*

  •  moveDirection = mytarget-currentPos;*

  •  moveDirection.y = 0; // ignore vertical distance before normalization*

_ moveDirection = moveDirection.normalized * currentSpeed;_

  • }*

_ moveDirection.y -= currentGravity * Time.deltaTime;_
_ controller.Move(moveDirection * Time.deltaTime);_

  • currentObject.transform.rotation = getTerrainRot(mytarget,currentPos,currentRot);*
    }
    }
    But, if I call function of botActions in Script A not through class AntWorkerm, everything works fine.I suspect that something wrong with constructor (( but can’t find where.
    Exception:
    NullReferenceException: Object reference not set to an instance of an object
    Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.String cacheKeyName, System.Type[] cacheKeyTypes, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
    Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.Object[] args, System.String cacheKeyName, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
    Boo.Lang.Runtime.RuntimeServices.Invoke (System.Object target, System.String name, System.Object[] args)
    antWorker1.Update () (at Assets/gScripts/classes/Animal/Insect/antWorker1.js:53)
    Thanks
2

“Object reference not set to an instance of an object” means that you are trying to use a variable that is null (empty) instead a variable pointing to an active object.

What you need is to assign the variable correct.

From your constructor, I think you make the error when you have the same variable name for both parameter to the constructor + using it as class variable. Perhaps this version will do it?:

class AntWorker

class AntWorker
{

    var goParent:GameObject;
    var patrolSpeed:int = 20;
    var gravity:int = 20;
    var botAction:botActions;

    public function AntWorker(goCaller:GameObject)
    {   
          goParent = goCaller;
          botAction = new botActions();
    }

    function patrolMove(target:Vector3)
    {
          botAction.simMove(currentObject,target,patrolSpeed,gravity);
    }

}

If thats not the problem, then try using Debug.Log(variablename) to see if it writes Object or Null in the Console when it hits the line.

usually I write them like this:

Debug.Log("Gameobject Enemy: " + goEnemy)

Once I find a line that says “null” instead of the object, I know where it goes wrong.