Added ability to customize generic object field drawer

Author: SolidAlloy

.GenericUnityInternals/GenericUnityEditorInternals/EditorGUIHelper.cs

@@ -14,7 +14,7 @@ public static class EditorGUIHelper
         [PublicAPI]
         public static Object GenericObjectField(Rect position, GUIContent label, Object currentTarget, Type objType, bool allowSceneObjects)
         {
-            return ObjectFieldInternal(position, label, currentTarget, allowSceneObjects, new ObjectFieldHelper(currentTarget, objType));
+            return GenericObjectField(position, label, currentTarget, allowSceneObjects, new ObjectFieldHelper(currentTarget, objType));
         }
 
         /// <summary>
@@ -25,24 +25,20 @@ public static void GenericObjectField(Rect position, SerializedProperty property
         {
             GUIContent propertyLabel = EditorGUI.BeginProperty(position, label, property);
 
-            ObjectFieldInternal(position, property, label == null ? null : propertyLabel);
-
-            EditorGUI.EndProperty();
-        }
-
-        private static void ObjectFieldInternal(Rect position, SerializedProperty property, [CanBeNull] GUIContent label)
-        {
             Object objectBeingEdited = property.serializedObject.targetObject;
 
             // Allow scene objects if the object being edited is NOT persistent
             bool allowSceneObjects = ! (objectBeingEdited == null || EditorUtility.IsPersistent(objectBeingEdited));
 
-            property.objectReferenceValue = ObjectFieldInternal(position, label, property.objectReferenceValue,
+            property.objectReferenceValue = GenericObjectField(position, label == null ? null : propertyLabel, property.objectReferenceValue,
                 allowSceneObjects, new ObjectFieldHelper(property));
+
+            EditorGUI.EndProperty();
         }
 
-        private static Object ObjectFieldInternal(Rect position, [CanBeNull] GUIContent label, Object currentTarget,
-            bool allowSceneObjects, ObjectFieldHelper helper)
+        [PublicAPI]
+        public static Object GenericObjectField(Rect position, [CanBeNull] GUIContent label, Object currentTarget,
+            bool allowSceneObjects, in ObjectFieldHelper helper)
         {
             const EditorGUI.ObjectFieldVisualType visualType = EditorGUI.ObjectFieldVisualType.IconAndText;
 

.GenericUnityInternals/GenericUnityEditorInternals/ObjectFieldHelper.cs

@@ -10,7 +10,7 @@
     /// When drawing ObjectField, there are things that need to be done differently for <see cref="Type"/> and <see cref="SerializedProperty"/>.
     /// This helper encapsulates such parts of the code so that the main method contains the same logic for Type and SerializedProperty.
     /// </summary>
-    internal readonly struct ObjectFieldHelper
+    public readonly struct ObjectFieldHelper
     {
         public readonly Type ObjType;
         public readonly Object CurrentTarget;
@@ -19,21 +19,25 @@ internal readonly struct ObjectFieldHelper
 
         private readonly SerializedProperty _property;
 
+        private readonly Func<Object, bool> _validateObjectCustom;
+
         public ObjectFieldHelper(Object currentTarget, Type type)
         {
             ObjType = type;
             CurrentTarget = currentTarget;
             _property = null;
+            _validateObjectCustom = null;
         }
 
-        public ObjectFieldHelper(SerializedProperty property)
+        public ObjectFieldHelper(SerializedProperty property, Func<Object, bool> validateObjectCustom = null)
         {
             _property = property;
             ObjType = GenericTypeHelper.GetGenericType(property);
             CurrentTarget = property.objectReferenceValue;
+            _validateObjectCustom = validateObjectCustom;
         }
 
-        public Object ValidateObjectFieldAssignment(Object[] references, EditorGUI.ObjectFieldValidatorOptions options)
+        internal Object ValidateObjectFieldAssignment(Object[] references, EditorGUI.ObjectFieldValidatorOptions options)
         {
             if (references.Length == 0)
                 return null;
@@ -113,9 +117,20 @@ private Object ValidateAssignmentForType(Object[] references)
 
         private Object ValidateAssignmentForProperty(Object[] references, EditorGUI.ObjectFieldValidatorOptions options)
         {
-            if (references[0] == null || ! EditorGUI.ValidateObjectReferenceValue(_property, references[0], options))
+            if (references[0] == null)
                 return null;
 
+            if (options == EditorGUI.ObjectFieldValidatorOptions.None && _validateObjectCustom != null)
+            {
+                if ( ! _validateObjectCustom(references[0]))
+                    return null;
+            }
+            else
+            {
+                if ( ! EditorGUI.ValidateObjectReferenceValue(_property, references[0], options))
+                    return null;
+            }
+
             if (EditorSceneManager.preventCrossSceneReferences &&
                 EditorGUI.CheckForCrossSceneReferencing(references[0], _property.serializedObject.targetObject))
             {

Editor/Drawers/CreatableObjectDrawer.cs

@@ -40,15 +40,15 @@ static CreatableObjectDrawer()
 
         public override void OnGUI(Rect rect, SerializedProperty property, GUIContent label)
         {
-            (_, Type type) = property.GetFieldInfoAndType();
+            Type propertyType = property.GetObjectType();
 
-            if (!type.InheritsFrom(typeof(ScriptableObject)) && !type.InheritsFrom(typeof(MonoBehaviour)))
+            if (!propertyType.InheritsFrom(typeof(ScriptableObject)) && !propertyType.InheritsFrom(typeof(MonoBehaviour)))
             {
                 EditorGUILayoutHelper.DrawErrorMessage("Creatable attribute can only be used on ScriptableObjects and MonoBehaviours.");
                 return;
             }
 
-            if (type.IsAbstract)
+            if (propertyType.IsAbstract)
             {
                 EditorGUILayoutHelper.DrawErrorMessage("Creatable attribute can only be used on fields of non-abstract type.");
                 return;
@@ -65,32 +65,37 @@ public override void OnGUI(Rect rect, SerializedProperty property, GUIContent la
             (var objectRect, var buttonRect) = rect.CutVertically(buttonWidth, true);
             objectRect.width -= paddingBetween;
 
-            GenericObjectDrawer.ObjectField(objectRect, property, label);
+            DrawObjectField(objectRect, property, label);
 
             if ( ! GUI.Button(buttonRect, "+"))
                 return;
 
             // this is for scriptable objects
-            if (type.InheritsFrom(typeof(ScriptableObject)))
+            if (propertyType.InheritsFrom(typeof(ScriptableObject)))
             {
-                CreateScriptableObject(property, type);
+                CreateScriptableObject(property, propertyType);
             }
             else
             {
-                CreateMonoBehaviour(property, type);
+                CreateMonoBehaviour(property, propertyType);
             }
         }
 
+        protected virtual void DrawObjectField(Rect objectRect, SerializedProperty property, GUIContent label)
+        {
+            GenericObjectDrawer.ObjectField(objectRect, property, label);
+        }
+
         #region Create Scriptable Object
 
-        private void CreateScriptableObject(SerializedProperty property, Type type)
+        private static void CreateScriptableObject(SerializedProperty property, Type type)
         {
             var asset = CreateAsset(property, type);
             property.objectReferenceValue = asset;
             EditorGUIUtility.PingObject(asset);
         }
 
-        private ScriptableObject CreateAsset(SerializedProperty property, Type type)
+        private static ScriptableObject CreateAsset(SerializedProperty property, Type type)
         {
             var folderPath = ProjectWindowUtilProxy.GetActiveFolderPath();
 
@@ -121,12 +126,12 @@ private ScriptableObject CreateAsset(SerializedProperty property, Type type)
             return asset;
         }
 
-        private bool IsValidPath(string path)
+        private static bool IsValidPath(string path)
         {
             return ! string.IsNullOrEmpty(path) && IsInProject(path) && HasCorrectExtension(path);
         }
 
-        private bool IsInProject(string path)
+        private static bool IsInProject(string path)
         {
             if (PathHelper.IsSubPathOf(path, _assetsPath) || PathHelper.IsSubPathOf(path, _packagesPath))
                 return true;
@@ -135,7 +140,7 @@ private bool IsInProject(string path)
             return false;
         }
 
-        private bool HasCorrectExtension(string path)
+        private static bool HasCorrectExtension(string path)
         {
             if (path.EndsWith(".asset"))
                 return true;
@@ -152,7 +157,7 @@ private bool HasCorrectExtension(string path)
         private const string PropertyPathKey = "CreatableObjectDrawer_PropertyPath";
         private const string AddedComponentTypeKey = "CreatableObjectDrawer_AddedComponent";
 
-        private void CreateMonoBehaviour(SerializedProperty property, Type type)
+        public static void CreateMonoBehaviour(SerializedProperty property, Type type, Action<Component, bool> onComponentAdded = null)
         {
             var parentComponent = property.serializedObject.targetObject as MonoBehaviour;
 
@@ -163,6 +168,8 @@ private void CreateMonoBehaviour(SerializedProperty property, Type type)
 
             var component = AddComponentHelper.AddComponent(gameObject, type, out bool reloadRequired);
 
+            onComponentAdded?.Invoke(component, reloadRequired);
+
             if (reloadRequired)
             {
                 PersistentStorage.SaveData(TargetComponentKey, property.serializedObject.targetObject);