NullReferenceException on GetComponent of Prefab Instance

Questions & Answers
1

I’m running into a problem with trying to access variables on a script attached to an instanced prefab. My code is such (Boo):

def Update ():
	newZombie as GameObject = Instantiate(zombiePrefabObj, Vector3(0, 0, 0), Quaternion.identity)
...
	enemies = GameObject.FindGameObjectsWithTag("zombie")
	currentZombie = enemies[0].GetComponent("zombieScript") as zombieScript
...
	for zombieObj in enemies:
		zombie = zombieObj.GetComponent("zombieScript") as zombieScript
		if Vector2.Distance(zombie.spriteRect.center, player.spriteRect.center) <
		Vector2.Distance(currentZombie.spriteRect.center, player.spriteRect.center):
			currentZombie = zombie
...
	if currentZombie.health == 0:
		Destroy(currentZombie)
		player.score += 100

...

def OnGUI ():
	enemies = GameObject.FindGameObjectsWithTag("zombie")
	for obj as GameObject in enemies:
		zombie = obj.GetComponent("zombieScript") as zombieScript
		if zombie.visible == true:
			zombie.Draw()

For some reason, when an enemy is destroyed, in (I think) the very same frame I run into a NullReferenceException (“Object reference not set to an instance of an object”) in the OnGUI function, specifically in the “if visible==true” line. I’ve confirmed via debug output that obj is not null, yet for some reason obj.GetComponent(“zombieScript”) returns null. What am I doing wrong here?

I’m wondering if maybe it’s a race, but Destroy() should be finished by the time OnGUI() runs as I understand it so I’m not sure why finding the GOs in OnGUI would return an object that was destroyed in Update.

2

Destroy(currentZombie)

It removes the component, but the object remains. If you want to destroy the whole object, use:

Destroy(currentZombie.gameObject)