troubleshooting NullReferenceException

Questions & Answers
1

I’m getting a “nullreferenceexception” error from the following code:

void OnCollisionEnter()
{
	GameObject landingPadLight = GameObject.Find ("landingPadLight");
	print(landingPadLight.light.intensity);
}

the exact error is:

NullReferenceException
givefuel.OnCollisionEnter () (at Assets/givefuel.cs:17)

the script is attached to an object that isn’t hte light, but I want that object to turn the light on when it’s collided with and so far I can’t even access the intensity of it.

2

GameObject.Find() is likely not finding an object. You should be checking the return result before trying to access the object.

if (landingPadLight)
{
    print(landingPadLight.light.intensity);
}
3

OnCollisionEnter never work with me. But the right assignature is void OnCollisionEnter (Collision Target), where the Target is your target of collision. Try assigning like that and if that din’t work try with

void OnTriggerEnter(Collider objectCollider)
    	{
    	    if(objectCollider.tag=="Player")
    		{
    			GameObject landingPadLight = GameObject.Find ("landingPadLight");
    			
    			if(landingPadLight)
        			print(landingPadLight.light.intensity);
    			else
    				Debug.Log ("It didn't work");
    		}
    	}

if you use this you must have a collider (BoxCollider, CapsulCollider, etc) in your object, and there you must say that isTrigger activating that variable.

see #12 Making a character respawn in Unity 3d game engine - YouTube or #25 - Destroying objects in Unity3D - YouTube