[ButtonMethod] not work in list item

[CharlieDreemur]

[ButtonMethod] not work in list item

[NeilJnDa]

I think it might be related to prefabs. I found that, if the game object is not from a prefab, this button method in editor works fine, the value is not lost after playing.
[ButtonMethod] void FindCollider() { m_Collider = GetComponent<Collider>(); }
However, if the gameobject is from a prefab. In editor, the change made by this method is not registered. It will be lost after playing.

I guess RecordPrefabInstancePropertyModifications() or SetDirty() would help. I will try it later when I have time.

[NeilJnDa]

It happened to me recently. In a button method I do something like list.Add() and list.Clear(), but the list is messed up:

1. The list in the prefab is changed, even though I did not change the prefab.
2. Non-null items ref in the list are cleared when clicking Play. Null items are still in the list.
   Hope it can be fixed soon

[Deadcows]

[ButtonMethod] do works in an independent item, but it fail when come to the list item in a list/dictionary

Unfortunately, ButtonMethod is restricted to the root of MonoBehaviour or ScriptableObject. It wouldn't work with serialized custom type, but it will be shown through DisplayInspector Attribute. So, if you will use SO or MB in a list, you can do it like that (elements of the list are child MBs):

I know it's not a universal solution, but it is the only way, currently, to display buttons in a list.
Nowadays I'm using Odin inspector to do this kind of things, it works fine along with MyBox.
Extending this attribute to work with any serialized type is possible, but not in my priority. Would appreciate any contributions to the codebase 😅🙌🏻

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I think it might be related to prefabs. I found that, if the game object is not from a prefab, this button method in editor works fine, the value is not lost after playing. [ButtonMethod] void FindCollider() { m_Collider = GetComponent<Collider>(); } However, if the gameobject is from a prefab. In editor, the change made by this method is not registered. It will be lost after playing.

Yep, you should definitely mark dirty any object, if you change its serialized data in the code during edit-time. Unity doesn't know that you changed the m_Collider field or resized the serialized list, so it won't save changes on the disc and they will be wiped out on domain reload.
The reason why changes weren't lost the first time is probably because you changed something else via inspector (this way the object was marked dirty internally) and all serialized data was successfully saved 🤔.
Something like this as a rule of thumb:

#if UNITY_EDITOR
[ButtonMethod] void FindCollider() { 
    m_Collider = GetComponent<Collider>();
    UnityEditor.EditorUtility.SetDirty(gameObject);
 }
#endif