Add type picker when creating abstract class or interface

Source/Editor/CustomEditors/Editors/GenericEditor.cs

@@ -711,21 +711,44 @@ namespace FlaxEditor.CustomEditors.Editors
                 {
                     // Check if it's an object type that can be created in editor
                     var type = Values.Type;
-                    if (type != ScriptMemberInfo.Null && type.CanCreateInstance)
+                    if (type != ScriptMemberInfo.Null)
                     {
-                        layout = layout.Space(20);
-
-                        const float ButtonSize = 14.0f;
-                        var button = new Button
+                        ScriptType[] types = null;
+                        if (type.IsAbstract || type.IsInterface)
                         {
-                            Text = "+",
-                            TooltipText = "Create a new instance of the object",
-                            Size = new Float2(ButtonSize, ButtonSize),
-                            AnchorPreset = AnchorPresets.MiddleRight,
-                            Parent = layout.ContainerControl,
-                            Location = new Float2(layout.ContainerControl.Width - ButtonSize - 4, (layout.ContainerControl.Height - ButtonSize) * 0.5f),
-                        };
-                        button.Clicked += () => SetValue(Values.Type.CreateInstance());
+                            // Show picker with all types that implement specific class/interface but are not abstract
+                            types = Editor.Instance.CodeEditing.All.Get().Where(x => !x.IsAbstract && x.CanCreateInstance && type.IsAssignableFrom(x)).ToArray();
+                        }
+                        else if (type.CanCreateInstance)
+                        {
+                            types = [type];
+                        }
+
+                        if (types != null && types.Length != 0)
+                        {
+                            layout = layout.Space(20);
+
+                            const float ButtonSize = 14.0f;
+                            var button = new Button
+                            {
+                                Text = "+",
+                                TooltipText = "Create a new instance of the object",
+                                Size = new Float2(ButtonSize, ButtonSize),
+                                AnchorPreset = AnchorPresets.MiddleRight,
+                                Parent = layout.ContainerControl,
+                                Location = new Float2(layout.ContainerControl.Width - ButtonSize - 4, (layout.ContainerControl.Height - ButtonSize) * 0.5f),
+                            };
+                            if (types.Length == 1)
+                            {
+                                // Single type
+                                button.Clicked += () => SetValue(Values.Type.CreateInstance());
+                            }
+                            else
+                            {
+                                // Picker
+                                button.Clicked += () => FlaxEditor.GUI.TypeSearchPopup.Show(button, new Float2(0, button.Height), types, scriptType => { SetValue(scriptType.CreateInstance()); });
+                            }
+                        }
                     }
 
                     layout.Label("<null>");

Source/Editor/GUI/Popups/TypeSearchPopup.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
 using System;
+using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
 using FlaxEditor.History;
@@ -131,6 +132,18 @@ namespace FlaxEditor.GUI
             SortItems();
         }
 
+        private TypeSearchPopup(IEnumerable<ScriptType> items, Action<ScriptType> selected)
+        {
+            _isValid = null;
+            _selected = selected;
+
+            ItemClicked += OnItemClicked;
+
+            foreach (var item in items)
+                AddItem(new TypeItemView(item));
+            SortItems();
+        }
+
         private bool IsHideAttributes(object[] attributes)
         {
             return attributes.FirstOrDefault(IsHideAttribute) == null;
@@ -162,6 +175,21 @@ namespace FlaxEditor.GUI
             return popup;
         }
 
+        /// <summary>
+        /// Shows the popup.
+        /// </summary>
+        /// <param name="showTarget">The show target.</param>
+        /// <param name="showTargetLocation">The show target location.</param>
+        /// <param name="items">Collection of types to display available to pick.</param>
+        /// <param name="selected">Event called on asset item pick.</param>
+        /// <returns>The dialog.</returns>
+        public static TypeSearchPopup Show(Control showTarget, Float2 showTargetLocation, IEnumerable<ScriptType> items, Action<ScriptType> selected)
+        {
+            var popup = new TypeSearchPopup(items, selected);
+            popup.Show(showTarget, showTargetLocation);
+            return popup;
+        }
+
         /// <inheritdoc />
         public override void OnDestroy()
         {