Unity 修改Prefab实例将Transform变为RectTransform

引用：Is there a way to destroy/replace a GameObject that is inside or part of a Prefab instance?
Changing Transform on a Prefab instance (jiantou) is not allowed.
这里用到的需求是做ui特效时将3Dmesh 渲染到ui层，用的ugui，ugui依赖于RectTransform，所以就有这个问题

将Prefab应用的Model对象的Transform修改为RectTransform

默认Model对象导入Transform组件，但是在ui中有些组件需要RectTransform组件，所以就需要强制将Transform变为RectTransform，这里通过调整Hierarchy面板内的prefab实例并且应用到prefab中，来完成修改，当然还有一个简单方法就是直接修改prefab

/// <summary>/// 把Prefab中的Transform替换为RectTransform/// 有个不足的地方是prefab的继承关系会丢失（Variant关系丢失）/// 如果一个prefab中引用另一个prefab，这种关系也会丢失/// </summary>/// <typeparam name="T">RectTransform</typeparam>/// <param name="obj"></param>private void AddComponentFromPrefab<T>(GameObject obj)  where T :UnityEngine.Component{PrefabAssetType prefabType = PrefabUtility.GetPrefabAssetType(obj);//Debug.Log($"AddComponentFromPrefab,name:{obj.name},PrefabAssetType:{prefabType}");switch (prefabType){case PrefabAssetType.Regular:case PrefabAssetType.Variant://获取prefab实例的根节点GameObject prefabRoot = PrefabUtility.GetOutermostPrefabInstanceRoot(obj);//获取prefab资源，在project中的GameObject prefabAsset = PrefabUtility.GetCorrespondingObjectFromSource(obj);//Object prefabAsset = PrefabUtility.GetCorrespondingObjectFromOriginalSource(obj);//获取资源的路径名字string assetPath = AssetDatabase.GetAssetPath(prefabAsset);//Debug.Log(assetPath);//断开Model的联系，如果是Model是禁止修改RectTransform的PrefabUtility.UnpackPrefabInstance(prefabRoot, PrefabUnpackMode.Completely, InteractionMode.AutomatedAction); //有个不足的地方是prefab的继承关系会丢失,这里是完全断开连接，非完全的方式没有测试PrefabUtility.SaveAsPrefabAssetAndConnect(prefabRoot, assetPath, InteractionMode.AutomatedAction);//修改prefab的RectTransform，如果修改实例的RectTransfom是失败的（Model虽然断开连接，但是还是禁止直接修改prefab实例的RectTransfom）GameObject pobj = PrefabUtility.LoadPrefabContents(assetPath);var ts=pobj.GetComponentsInChildren<Transform>();foreach (var t in ts)if (!(t is RectTransform))t.gameObject.AddComponent<T>();PrefabUtility.SaveAsPrefabAsset(pobj, assetPath);PrefabUtility.UnloadPrefabContents(pobj);break;case PrefabAssetType.Model:PrefabUtility.UnpackPrefabInstanceAndReturnNewOutermostRoots(obj, PrefabUnpackMode.Completely);if (!(obj.transform is T))obj.AddComponent<T>();break;default:break;}}

测试

AddComponentFromPrefab<RectTransform>(gameObject);

将测试代码写到Start方法中，且脚本设置[ExecuteInEditMode]标签，挂载prefab跟节点，
测试结果：

结果：

执行代码后Model引用变为prefab内的普通物体，切换修改成功RectTransform，并且prefab也已经修改成功

Prefab和GameObject的正向和逆向查找引用

转自 Unity研究院之Prefab和GameObject的正向和逆向查找引用

[MenuItem("Assets/Check Prefab Use ?")]private static void OnSearchForReferences(){//确保鼠标右键选择的是一个Prefabif(Selection.gameObjects.Length != 1){return;}//遍历所有游戏场景foreach(EditorBuildSettingsScene scene in EditorBuildSettings.scenes){if(scene.enabled){//打开场景EditorApplication.OpenScene(scene.path);//获取场景中的所有游戏对象GameObject []gos = (GameObject[])FindObjectsOfType(typeof(GameObject));foreach(GameObject go  in gos){//判断GameObject是否为一个Prefab的引用if(PrefabUtility.GetPrefabType(go)  == PrefabType.PrefabInstance){UnityEngine.Object parentObject = EditorUtility.GetPrefabParent(go); string path = AssetDatabase.GetAssetPath(parentObject);//判断GameObject的Prefab是否和右键选择的Prefab是同一路径。if(path == AssetDatabase.GetAssetPath(Selection.activeGameObject)){//输出场景名，以及Prefab引用的路径Debug.Log(scene.path  + "  " + GetGameObjectPath(go));}}}}}}public static string GetGameObjectPath(GameObject obj){string path = "/" + obj.name;while (obj.transform.parent != null){obj = obj.transform.parent.gameObject;path = "/" + obj.name + path;}return path;}

Unity2018.4的Prefab Variant(Prefab变种)功能

转自[Unity]Unity2018.4的Prefab Variant(Prefab变种)功能

Unity 2018.4中送了一个新的功能: Prefab Variant

思路是, Prefab Variant 继承于一个父Prefab, 父Prefab属性修改后:

(1)如果子Prefab的某些属性不动, 则父Prefab的属性影响子Prefab的属性, 此为 [属性继承]
(2)如果对子Prefab的某些属性进行修改/覆盖, 则父Prefab的属性无法影响, 此为 [属性定制]

创建Prefab Variant的方法为: 把Prefab从Hierarchy再次拉到Project中,选择 Prefab Variant

用处举例:

比如做一个UGUI窗体模板, 上面有标题文字和关闭按钮

邮件窗体继承于此窗体模板,制作成为一个PrefabVariant, 但是标题文字定制修改为”邮件”

这时,可以通过修改窗体模板中的关闭按钮,对所有派生的窗体按钮进行修改

附:以下为官方对PrefabAssetType的解释:

    public enum PrefabAssetType{//// 摘要://     The object being queried is not part of a Prefab at all.NotAPrefab = 0, // 不是Prefab//// 摘要://     The object being queried is part of a regular Prefab.Regular = 1, // 常规的Prefab//// 摘要://     The object being queried is part of a Model Prefab.Model = 2, // 模型(例如:FBX)//// 摘要:// The object being queried is part of a Prefab Variant.// A Variant Prefab is a Prefab that is derived from another Prefab, // that be could be a Regular, Model or even Variant Prefab.Variant = 3, // Prefab变种//// 摘要://     The object being queried is part of a Prefab instance, but because the asset//     it missing the actual type of Prefab can’t be determined.MissingAsset = 4 // Prefab实例化出来的对象,但是Prefab被删了(红色)}