Updated README. Added warnings to PoolAsset and RefPooler if prefab is not assigned. Added several sample scenes to showcase Refpool features.

Author: BluePixelDev

Editor/EditorUtil.cs renamed to Editor/EditorItems.cs

@@ -3,15 +3,14 @@
 
 namespace BP.RefPool.Editor
 {
-    public static class EditorUtil
+    internal static class EditorItems
     {
-
         [MenuItem("GameObject/RefPool/Pool", false, 10)]
         public static void CreatePool(MenuCommand menuCommand)
         {
             GameObject go = new("Pool");
             go.AddComponent<RefPooler>();
-            EditorCreeate(menuCommand, go);
+            EditorCreate(menuCommand, go);
         }
 
         [MenuItem("GameObject/RefPool/Group", false, 10)]
@@ -25,18 +24,18 @@ public static void CreateGroup(MenuCommand menuCommand)
                 child.transform.SetParent(root.transform);
                 rootGroup.Add(child.GetComponent<RefPooler>());
             }
-            EditorCreeate(menuCommand, root);
+            EditorCreate(menuCommand, root);
         }
 
 
         [MenuItem("GameObject/RefPool/Spawner", false, 10)]
         public static void CreateSpawner(MenuCommand menuCommand)
         {
             GameObject root = new("Spawner", typeof(RefSpawner));
-            EditorCreeate(menuCommand, root);
+            EditorCreate(menuCommand, root);
         }
 
-        private static void EditorCreeate(MenuCommand menuCommand, params GameObject[] gameobjects)
+        private static void EditorCreate(MenuCommand menuCommand, params GameObject[] gameobjects)
         {
             foreach (var go in gameobjects)
             {

Editor/EditorUtil.cs.meta renamed to Editor/EditorItems.cs.meta

@@ -0,0 +1,31 @@
+using UnityEditor;
+using UnityEditor.UIElements;
+using UnityEngine.UIElements;
+
+namespace BP.RefPool.Editor
+{
+    public static class EditorUtils
+    {
+        public static void TrackVisibilityBasedOnProperty(
+           this VisualElement element,
+           SerializedProperty property,
+           System.Func<SerializedProperty, bool> condition
+        )
+        {
+            element.style.display = condition(property) ? DisplayStyle.Flex : DisplayStyle.None;
+            element.TrackPropertyValue(property, val =>
+                element.style.display = condition(val) ? DisplayStyle.Flex : DisplayStyle.None
+            );
+        }
+
+        public static void PropertyAction(
+            this VisualElement element,
+            SerializedProperty property,
+            System.Action<SerializedProperty> action
+        )
+        {
+            action(property);
+            element.TrackPropertyValue(property, action);
+        }
+    }
+}

Editor/EditorUtils.cs

@@ -13,6 +13,11 @@ public override VisualElement CreateInspectorGUI()
         {
             var root = new VisualElement();
             treeAsset.CloneTree(root);
+
+            var helpBox = root.Q<HelpBox>("help-box");
+            var prefabProp = serializedObject.FindProperty("prefab");
+
+            helpBox.TrackVisibilityBasedOnProperty(prefabProp, (prop) => prop.boxedValue == null);
             return root;
         }
     }

Editor/EditorUtils.cs.meta

@@ -1,8 +1,9 @@
 <ui:UXML xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ui="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements" noNamespaceSchemaLocation="../../../../UIElementsSchema/UIElements.xsd" editor-extension-mode="True">
     <ui:TextField label="Display Name" binding-path="displayName" />
     <uie:ObjectField label="Prefab" type="UnityEngine.GameObject, UnityEngine.CoreModule" binding-path="prefab" />
-    <ui:Toggle label="Reuse Objects" data-source-path="reuseObjects" />
+    <ui:Toggle label="Reuse Objects" data-source-path="reuseObjects" binding-path="reuseObjects" />
     <ui:Label text="Size" style="-unity-text-align: upper-center; -unity-font-style: bold; font-size: 16px; margin-top: 10px;" />
     <ui:IntegerField label="Init Size" value="0" binding-path="initSize" />
     <ui:IntegerField label="Max Size" value="0" binding-path="maxSize" />
+    <ui:HelpBox text="Prefab is not assigned" message-type="Warning" name="help-box" />
 </ui:UXML>

Editor/PoolAsset/PoolAssetEditor.cs

@@ -1,6 +1,5 @@
 <ui:UXML xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ui="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements" noNamespaceSchemaLocation="../../../../UIElementsSchema/UIElements.xsd" editor-extension-mode="True">
     <ui:TextField label="Display Name" binding-path="displayName" />
     <ui:EnumField label="Pick Mode" value="Random" type="BP.RefPool.PoolPickMode, BP.RefPool" binding-path="pickMode" />
-    <ui:Label text="Pools" style="margin-top: 10px; font-size: 16px; -unity-font-style: bold; -unity-text-align: upper-center;" />
     <ui:ListView binding-path="pools" reorderable="true" show-bound-collection-size="false" show-add-remove-footer="true" reorder-mode="Animated" show-border="true" virtualization-method="DynamicHeight" />
 </ui:UXML>

Editor/PoolAsset/UXML_PoolAsset.uxml

@@ -2,5 +2,5 @@
     <ui:GroupBox>
         <ui:Label text="&lt;b&gt;RefItem&lt;/b&gt; acts as handle for pooled items.&lt;br&gt;&lt;b&gt;&lt;i&gt;&lt;color=red&gt;Removal during runtime can result in unexpected behaviour." style="white-space: normal; -unity-text-align: upper-center;" />
     </ui:GroupBox>
-    <uie:PropertyField binding-path="onReset" label="On Reset" />
+    <uie:PropertyField binding-path="onUse" label="OnUse" />
 </ui:UXML>

Editor/PoolGroup/UXML_PoolGroup.uxml

@@ -1,5 +1,4 @@
 using UnityEditor;
-using UnityEditor.UIElements;
 using UnityEngine;
 using UnityEngine.UIElements;
 
@@ -25,18 +24,21 @@ public override VisualElement CreateInspectorGUI()
             treeAsset.CloneTree(root);
 
             var initSizeSlider = root.Q<SliderInt>("init-size");
+            var helpBox = root.Q<HelpBox>("help-box");
+            runtimeStats = root.Q("runtime-stats");
+            usageProgressBar = runtimeStats.Q<ProgressBar>("usage-progress");
+            capacityProgressBar = runtimeStats.Q<ProgressBar>("capacity-progress");
+
             var maxSizeProp = serializedObject.FindProperty("maxSize");
             var initSizeProp = serializedObject.FindProperty("initSize");
+            var prefabProp = serializedObject.FindProperty("prefab");
 
-            initSizeSlider.highValue = maxSizeProp.intValue;
-            initSizeSlider.TrackPropertyValue(maxSizeProp, (prop) =>
+            initSizeSlider.PropertyAction(initSizeProp, (prop) =>
             {
-                initSizeSlider.highValue = maxSizeProp.intValue;
+                initSizeSlider.highValue = prop.intValue;
             });
 
-            runtimeStats = root.Q("runtime-stats");
-            usageProgressBar = runtimeStats.Q<ProgressBar>("usage-progress");
-            capacityProgressBar = runtimeStats.Q<ProgressBar>("capacity-progress");
+            helpBox.TrackVisibilityBasedOnProperty(prefabProp, (prop) => prop.boxedValue == null);
 
             UpdateStatsVisibility(Application.isPlaying);
             EditorApplication.playModeStateChanged -= PlayModeChanged;

Editor/RefItem/UXML_RefItem.uxml

@@ -4,7 +4,7 @@
     <ui:IntegerField label="Max Size" value="0" binding-path="maxSize" />
     <ui:SliderInt label="Init Size" value="42" high-value="10" fill="false" show-input-field="true" binding-path="initSize" name="init-size" />
     <ui:Toggle label="Reuse Objects" binding-path="reuseObjects" />
-    <ui:VisualElement name="runtime-stats" style="flex-grow: 1;">
+    <ui:VisualElement name="runtime-stats" style="flex-grow: 0;">
         <ui:GroupBox>
             <ui:Label text="Runtime Stats" style="-unity-font-style: bold;" />
             <ui:VisualElement style="flex-grow: 0; flex-direction: row;">
@@ -17,4 +17,5 @@
             </ui:VisualElement>
         </ui:GroupBox>
     </ui:VisualElement>
+    <ui:HelpBox message-type="Warning" text="Prefab is not assigned" name="help-box" />
 </ui:UXML>