Fixes for pooling Unity UI, and automatic pool creation.

Assets/ObjectPool/Scripts/ObjectPool.cs

@@ -15,10 +15,10 @@ public class StartupPool
 
 	static ObjectPool _instance;
 	static List<GameObject> tempList = new List<GameObject>();
-	
+
 	Dictionary<GameObject, List<GameObject>> pooledObjects = new Dictionary<GameObject, List<GameObject>>();
 	Dictionary<GameObject, GameObject> spawnedObjects = new Dictionary<GameObject, GameObject>();
-	
+
 	public StartupPoolMode startupPoolMode;
 	public StartupPool[] startupPools;
 
@@ -64,18 +64,17 @@ public static void CreatePool(GameObject prefab, int initialPoolSize)
 			{
 				bool active = prefab.activeSelf;
 				prefab.SetActive(false);
-				Transform parent = instance.transform;
 				while (list.Count < initialPoolSize)
 				{
 					var obj = (GameObject)Object.Instantiate(prefab);
-					obj.transform.parent = parent;
+					obj.transform.SetParent(instance.transform, false); // worldPositionStays=false to keep UI objects spawning consistently
 					list.Add(obj);
 				}
 				prefab.SetActive(active);
 			}
 		}
 	}
-	
+
 	public static T Spawn<T>(T prefab, Transform parent, Vector3 position, Quaternion rotation) where T : Component
 	{
 		return Spawn(prefab.gameObject, parent, position, rotation).GetComponent<T>();
@@ -104,7 +103,8 @@ public static GameObject Spawn(GameObject prefab, Transform parent, Vector3 posi
 	{
 		List<GameObject> list;
 		Transform trans;
-		GameObject obj;
+		GameObject obj = null;
+		CreatePool(prefab.gameObject, 0); // will create pool if none exists
 		if (instance.pooledObjects.TryGetValue(prefab, out list))
 		{
 			obj = null;
@@ -118,7 +118,10 @@ public static GameObject Spawn(GameObject prefab, Transform parent, Vector3 posi
 				if (obj != null)
 				{
 					trans = obj.transform;
-					trans.parent = parent;
+					if (parent != null)
+					{
+						trans.SetParent(parent, false); // worldPositionStays=false to keep UI objects spawning consistently
+					}
 					trans.localPosition = position;
 					trans.localRotation = rotation;
 					obj.SetActive(true);
@@ -128,21 +131,15 @@ public static GameObject Spawn(GameObject prefab, Transform parent, Vector3 posi
 			}
 			obj = (GameObject)Object.Instantiate(prefab);
 			trans = obj.transform;
-			trans.parent = parent;
+			if (parent != null)
+			{
+				trans.SetParent(parent, false); // worldPositionStays=false to keep UI objects spawning consistently
+			}
 			trans.localPosition = position;
 			trans.localRotation = rotation;
 			instance.spawnedObjects.Add(obj, prefab);
-			return obj;
-		}
-		else
-		{
-			obj = (GameObject)Object.Instantiate(prefab);
-			trans = obj.GetComponent<Transform>();
-			trans.parent = parent;
-			trans.localPosition = position;
-			trans.localRotation = rotation;
-			return obj;
 		}
+		return obj;
 	}
 	public static GameObject Spawn(GameObject prefab, Transform parent, Vector3 position)
 	{
@@ -173,15 +170,20 @@ public static void Recycle(GameObject obj)
 	{
 		GameObject prefab;
 		if (instance.spawnedObjects.TryGetValue(obj, out prefab))
+		{
 			Recycle(obj, prefab);
+		}
 		else
+		{
+			Debug.LogWarning(obj.name + "can not be recycled because it was never pooled. It will be destroyed instead.");
 			Object.Destroy(obj);
+		}
 	}
 	static void Recycle(GameObject obj, GameObject prefab)
 	{
 		instance.pooledObjects[prefab].Add(obj);
 		instance.spawnedObjects.Remove(obj);
-		obj.transform.parent = instance.transform;
+		obj.transform.SetParent(instance.transform, false); // worldPositionStays=false to keep UI objects spawning consistently
 		obj.SetActive(false);
 	}
 
@@ -205,7 +207,7 @@ public static void RecycleAll()
 			Recycle(tempList[i]);
 		tempList.Clear();
 	}
-	
+
 	public static bool IsSpawned(GameObject obj)
 	{
 		return instance.spawnedObjects.ContainsKey(obj);
@@ -356,7 +358,7 @@ public static void CreatePool(this GameObject prefab, int initialPoolSize)
 	{
 		ObjectPool.CreatePool(prefab, initialPoolSize);
 	}
-	
+
 	public static T Spawn<T>(this T prefab, Transform parent, Vector3 position, Quaternion rotation) where T : Component
 	{
 		return ObjectPool.Spawn(prefab, parent, position, rotation);
@@ -405,7 +407,7 @@ public static GameObject Spawn(this GameObject prefab)
 	{
 		return ObjectPool.Spawn(prefab, null, Vector3.zero, Quaternion.identity);
 	}
-	
+
 	public static void Recycle<T>(this T obj) where T : Component
 	{
 		ObjectPool.Recycle(obj);
@@ -509,4 +511,4 @@ public static void DestroyAll<T>(this T prefab) where T : Component
 	{
 		ObjectPool.DestroyAll(prefab.gameObject);
 	}
-}
+}

ObjectPool.userprefs

@@ -1,10 +1,6 @@
-<Properties>
-  <MonoDevelop.Ide.Workspace ActiveConfiguration="Debug" PreferredExecutionTarget="MonoDevelop.Default" />
-  <MonoDevelop.Ide.Workbench ActiveDocument="Assets/ObjectPool/Scripts/ObjectPool.cs">
-    <Files>
-      <File FileName="Assets/ObjectPool/Scripts/ObjectPool.cs" Line="4" Column="1" />
-    </Files>
-  </MonoDevelop.Ide.Workbench>
+<Properties StartupItem="Assembly-CSharp.csproj">
+  <MonoDevelop.Ide.Workspace ActiveConfiguration="Debug" PreferredExecutionTarget="Unity.Instance.Unity Editor" />
+  <MonoDevelop.Ide.Workbench />
   <MonoDevelop.Ide.DebuggingService.Breakpoints>
     <BreakpointStore />
   </MonoDevelop.Ide.DebuggingService.Breakpoints>

ProjectSettings/ProjectVersion.txt

@@ -0,0 +1,2 @@
+m_EditorVersion: 5.3.5f1
+m_StandardAssetsVersion: 0