Update class in editor but not when playing

There can be a time when you want monobehavior (or any class) to receive Update callbacks in editor.
For that you can use [ExecuteInEditMode]

However, sometimes this gets on the way, - you might want to use Start() only during the game, but it's ran after you exit play mode. Other horrible things might happen.

Sometimes things like EditorApplication.isPlayingOrWillChangePlayMode are not always working like you would expect, especially during the serialization.

It can be hard to detect when the editor stopped playing, to re-hook your functions back, etc

Here is code which allows any class (including Monobehavior) to receive update callbacks in the editor specifically when not playing.

Code (CSharp):

1.  
2. //Igor Aherne  www.facebook.com/igor.aherne
3. public class MyClass{        
4. #region update in editor NOT in play mode
5. #if UNITY_EDITOR
6.         [UnityEditor.Callbacks.DidReloadScripts]
7.         public static void OnRecompiledScripts() {
8.             UnityEditor.EditorApplication.playmodeStateChanged -= PlayModeStateChanged;
9.             UnityEditor.EditorApplication.playmodeStateChanged += PlayModeStateChanged;
10.  
11.             PlayModeStateChanged();
12.         }
13.  
14.  
15.  
16.         public static void PlayModeStateChanged() {
17.             Debug.Log("playmodeChanged");
18.             if (UnityEditor.EditorApplication.isPlayingOrWillChangePlaymode) {
19.                 toggle_allEditorUpdateHooks(false);
20.                 return;
21.             }
22.  
23.             //make sure all FSMs are getting updates
24.             toggle_allEditorUpdateHooks(true);
25.         }
26.  
27.  
28.         private static void toggle_allEditorUpdateHooks(bool isTrue) {
29.             MyClass[] myClasses = Component.FindObjectsOfType<MyClass>();
30.             foreach (MyClass myClass in myClasses) {
31.                 myClass.toggle_EditorUpdateHook(isTrue);
32.             }//end foreach
33.         }
34.  
35.  
36.         public void toggle_EditorUpdateHook(bool isOn) {
37.             UnityEditor.EditorApplication.update -= UpdateInEditor;
38.  
39.             if (isOn) {
40.                 UnityEditor.EditorApplication.update += UpdateInEditor;
41.             }
42.         }
43.  
44.  
45.         private void UpdateInEditor() {
46.              Debug.Log("running in editor, every frame, but not while playing the game")
47.         }
48. #endif
49. #endregion
50. }
51.