unity ScriptableObject 多态 Arrays 序列化

Question

The main issue is, I'm trying to use a polymorphic list in a ScriptableObject but its contents are lost when restarting Unity; code below.

---

So I've got a base class:

[Serializable]
public class BaseAction : ScriptableObject
{
    public virtual void OnGUI()
    {
    }

    public virtual void ExecuteAction()
    {
    }
}

And an inheriting class with a simple string attribute:

[Serializable]
public class DebugLogAction : BaseAction
{
    [SerializeField]
    private string debugText = default;

    public override void OnGUI()
    {
        debugText = EditorGUILayout.TextField(debugText);
    }

    public override void ExecuteAction()
    {
        Debug.Log(debugText);
    }
}

They all reunite in a ScriptableObject that contains a list of BaseActions:

[Serializable]
[CreateAssetMenu(fileName = "NewActionContainer", menuName = "ScriptableObjects/Action Container")]
public class ActionContainer : ScriptableObject
{
    [SerializeField]
    private List<BaseAction> actions = default;

    public void OnEnable()
    {
        if (actions == null)
        {
            actions = new List<BaseAction>();
        }
    }

    public void OnInspectorGUI()
    {
        foreach (var action in actions)
        {
            action.OnGUI();
        }

        if (GUILayout.Button("Add Debug Log Action"))
        {
            actions.Add(CreateInstance<DebugLogAction>());
        }
    }
}

I've written up a custom editor for the ActionContainer ScriptableObject which works fine, displaying the button for adding multiple actions which adds editable input fields:

[CustomEditor(typeof(ActionContainer)), CanEditMultipleObjects]
public class CustomActionContainerInspector : Editor
{
    private ActionContainer actionContainer;

    public void OnEnable()
    {
        actionContainer = (ActionContainer)target;
    }

    public override void OnInspectorGUI()
    {
        actionContainer.OnInspectorGUI();
    }
}

---

However, on restart of Unity, the content of the ScriptableObject is gone (assembly rebuilding is fine, playing/stopping the game keeps the data as well).

I've tried adding a field to BaseAction to check if the values are just sheared off the inheriting class, but no; the entire list of actions from the ActionContainer empties.

I believe there's an issue either with serializing or deserializing the elements from the list itself, since it's polymorphic, but I've got no idea how to debug or solve the issue; internet searches didn't get me to a solution either.

Answer 1

First of all in general you should not call your method OnGUI as this is also a built-in message in MonoBehaviour and might lead to confusion.

Your main pitfall I think is the dirty state.

If you don't mark objects dirty after changing them then your changes don't get saved correctly.

I think a quick fix for this would be to use EditorUtility.SetDirty

public override void OnGUI()
{
    EditorGUI.BeginChangeCheck();
    debugText = EditorGUILayout.TextField(debugText);
    if(EditorGUI.EndChangeCheck())
    {
        EditorUtility.SetDirty(this);
    }
}

or if you wan to properly support undo/redo then rather usingUndo.RecordObject

public override void OnGUI()
{
    EditorGUI.BeginChangeCheck();
    var newDebugText = EditorGUILayout.TextField(debugText);
    if(EditorGUI.EndChangeCheck())
    {
        Undo.RecordObject(this, "changed debug text");
        debugText = newDebugText;
    }
}

See also

• EditorGUI.BeginChangeCheck / EditorGUI.EndChangeCheck