NullReferenceException after build

Questions & Answers
1

I’m having problems after build. In preview everything works fine but after build there are errors.
After build I’m having the exception ‘NullReferenceException: Object reference not set to an instance of an object’ here:

void hideTreeOfObjects(GameObject ob){
	for (int i = 0; i < ob.transform.childCount; i++) {
	
		//for some reason child = null in build, but child != null in preview
		GameObject child = ob.transform.GetChild(i).gameObject; /*line 229*/
		
		try{
			child.GetComponent<MeshRenderer> ().enabled = false;
		}catch(MissingComponentException){}
		try{
			if (child.tag != "lostdetector" && !VRmode){
				child.GetComponent<Collider> ().enabled = false;
			}
		}catch(MissingComponentException){}
		try{
			child.GetComponent<LineRenderer> ().enabled = false;
		}catch(MissingComponentException){}
		hideTreeOfObjects (child);
	}
}

This function disables some components for every GameObject in a hierarchy tree. It’s called by this functions in the same script (UIManager.cs):

//[...]

public GameObject Indicators;

//[...]

void hideIndicators(){
	hideTreeOfObjects (Indicators);
}

public void OnClickRepository(){
	setMode (3);
	PathItem.hideAllPathPoints ();
	hideIndicators ();
	selectedObject = null;
	selectedObjectToCreate = null;
	refreshUI ();
}

void Start () {
	OnClickRepository ();
	refreshUI ();
	loadRepositoryUI ();0
}

This is the GameObject Indicators. It has only the transform component:

110681-tree.png

The GameObject Indicators is assigned properly in the inspector of the GameObject which uses the UIManager component:

110682-manager.png
110682-manager.png512×643 84.3 KB

Why is this happening?

2

I’ve solved it by catching the NullReferenceException. The problem was that Unity throws diferent exceptions in preview and in build. In preview I was getting the MissingComponentException when I was using a function of an inexistent component, but not the NullReferenceException.

So at the end all component function calls like

try{
    child.GetComponent<MeshRenderer> ().enabled = false;
}catch(MissingComponentException){}

have turned into this

try{
    try{
        child.GetComponent<MeshRenderer> ().enabled = false;
    }catch(NullReferenceException){}
}catch(MissingComponentException){}

But there are better solutions to enable/disable components for all the descendants of a specified object, like this one

public void Test2(GameObject ob)   
{
        MeshRenderer[] list = ob.GetComponentsInChildren<MeshRenderer>();
        Debug.Log("Found: " + list.Length);
        foreach (MeshRenderer rend in list)
        {
            Debug.Log("Disabling: " + rend.name);
            rend.enabled = false;
         }
 }