Another another **Setting the parent of a transform which resides in a prefab** problem, and OnValidate
The other questions about this error don't seem to be caused by the situation that I will show. I'm on Unity 5.3.4.
I have two prefabs, Parent and Child. Child is an empty GameObject (has just Transform component). Parent has the following script:
using UnityEngine;
public class TestParenting : MonoBehaviour {
public GameObject prefab;
public int dummy;
private void OnValidate() {
Debug.Log("validate testparenting. childs found: " + GetComponentsInChildren<Transform>(true).Length);
UpdateChild();
}
private void UpdateChild() {
// GetComponentsInChildren also returns the Transform in the parent
if (GetComponentsInChildren<Transform>(true).Length < 2)
NewChild();
}
private void NewChild() {
GameObject instance = Instantiate(prefab);
instance.name = "child";
instance.transform.SetParent(transform);
}
}
The expected behaviour is that Parent always have to have a Child, which is an instance of the Child prefab attached to the script in Editor, and checked in OnValidate. OnValidate is executed as a Unity event when any change occurs in the editor for the script, and in deserialization (not precisely sure about the moment in this last case).
I get the error when I hit the play button in Editor and Parent has no Child yet (and in other situations related to prefab modification). When I hit play and I get the error, I also get "Some objects were not cleaned up when closing the scene. (Did you spawn new GameObjects from OnDestroy?)".
I think it is a prefab serialization issue, but can't fix it.
What can I do to get rid of this error?
This also happens when scripts are reloaded. In this case, the second error doesn't happen, and an unparented Child is added to the scene.
Answer by brunoleos · Aug 30, 2016 at 07:15 PM
The workaround (not sure yet if it is a solution) I'm using is:
private void OnValidate() {
if (PrefabUtility.GetPrefabType(this) == PrefabType.PrefabInstance) {
UpdateChild();
}
}
Apparently, OnValidate is also called inside the prefab asset, and not just in the instance. I didn't know that.
Your answer
Follow this Question
Related Questions
How can I detect prefabs edited in the prefab editor in OnValidate? 2 Answers
what does the BUILD_ADDITIONAL-folder stands for ? 0 Answers
Editor script: Variable created on gameObject in editor set to missing on runtime 0 Answers
Instantiated prefab won't access text in scene 0 Answers
Weird behavior of prefabs generated and saved in a folder using C# script 0 Answers