Can't use DecoratorDrawer with ScriptableObject in Unity

Questions & Answers
1

I asked this on stackoverflow and even though I got a good answer, it’s not ideal and it’s sort of a hack.

I have this game object script:

public class PingPong : MonoBehaviour {
	[Test]
	public int value1 = 10;
	[Test]
	public int value2 = 10;
}

This TestAttribute.cs class

public class TestAttribute : PropertyAttribute {}

And this DecoratorDrawer extension class:

[CustomPropertyDrawer(typeof(TestAttribute))]
public class TestDecorator : DecoratorDrawer {
	public override void OnGUI(Rect position) {
		base.OnGUI(position);
		EditorGUILayout.LabelField("Hi", "hello");
	}
}

This works great!

But if I try to put the exact same thing in a ScriptableObject instance like this:

[CreateAssetMenu(fileName = "Example", menuName = "Example/Settings", order = 1)]
public class SpecialSettings : ScriptableObject {
	[Test]
	public int value1 = 10;
	[Test]
	public int value2 = 10;
}

It won’t do it and gives me this error:

ArgumentException: Getting control 4's position in a group with only 4 controls when doing Repaint
Aborting
UnityEngine.GUILayoutGroup.GetNext () (at C:/buildslave/unity/build/Modules/IMGUI/LayoutGroup.cs:117)
UnityEngine.GUILayoutUtility.DoGetRect (UnityEngine.GUIContent content, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Modules/IMGUI/GUILayoutUtility.cs:444)
UnityEngine.GUILayoutUtility.GetRect (UnityEngine.GUIContent content, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Modules/IMGUI/GUILayoutUtility.cs:404)
UnityEditor.InspectorWindow.CheckDragAndDrop (UnityEditor.Editor[] editors) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:622)
UnityEditor.InspectorWindow.OnGUI () (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:443)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:291)
UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:284)
UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:251)

Can anyone tell me whats wrong?

One thing that is worth pointing out is that the label can be multi line. I basically want a [Tooltip] that is just there, no mouseover to see it.

2

PropertyDrawers as well sa DecoratorDrawers can’t use GUILayout functions. You have to use the GUI / EditorGUI methods. Your OnGUI callback gets a Rect parameter which you have to use to draw your stuff. If you need more space you also need to override the GetHeight method and return the size you need.