Unity3D研究院之Prefab里面的Prefab关联问题（转）

转自http://www.xuanyusong.com/archives/3042

最近在做UI部分中遇到了这样的问题，就是Prefab里面预制了Prefab。可是在Unity里面一旦Prefab预制了Prefab那么内部的Prefab就失去关联。导致与如果要改内部的Prefab需要把所有引用的地方全部改一遍。今天在逛国外网站看到了一个老外的思路，原文在这里 http://framebunker.com/blog/poor-mans-nested-prefabs/
下面直接上代码

 

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using UnityEngine; #if UNITY_EDITOR using UnityEditor; using UnityEditor.Callbacks; #endif using System.Collections.Generic;   [ExecuteInEditMode] public class PrefabInstance : MonoBehaviour { public GameObject prefab;   #if UNITY_EDITOR // Struct of all components. Used for edit-time visualization and gizmo drawing public struct Thingy { public Mesh mesh; public Matrix4x4 matrix; public List<Material> materials; }   [System.NonSerializedAttribute] public List<Thingy> things = new List<Thingy> ();   void OnValidate () { things.Clear(); if (enabled) Rebuild (prefab, Matrix4x4.identity); }   void OnEnable () { things.Clear(); if (enabled) Rebuild (prefab, Matrix4x4.identity); }   void Rebuild (GameObject source, Matrix4x4 inMatrix) { if (!source) return;   Matrix4x4 baseMat = inMatrix * Matrix4x4.TRS (-source.transform.position, Quaternion.identity, Vector3.one);   foreach (MeshRenderer mr in source.GetComponentsInChildren(typeof (Renderer), true)) { things.Add(new Thingy () { mesh = mr.GetComponent<MeshFilter>().sharedMesh, matrix = baseMat * mr.transform.localToWorldMatrix, materials = new List<Material> (mr.sharedMaterials) }); }   foreach (PrefabInstance pi in source.GetComponentsInChildren(typeof (PrefabInstance), true)) { if (pi.enabled && pi.gameObject.activeSelf) Rebuild (pi.prefab, baseMat * pi.transform.localToWorldMatrix); } }   // Editor-time-only update: Draw the meshes so we can see the objects in the scene view void Update () { if (EditorApplication.isPlaying) return; Matrix4x4 mat = transform.localToWorldMatrix; foreach (Thingy t in things) for (int i = 0; i < t.materials.Count; i++) Graphics.DrawMesh (t.mesh, mat * t.matrix, t.materials[i], gameObject.layer, null, i); }   // Picking logic: Since we don't have gizmos.drawmesh, draw a bounding cube around each thingy void OnDrawGizmos () { DrawGizmos (new Color (0,0,0,0)); } void OnDrawGizmosSelected () { DrawGizmos (new Color (0,0,1,.2f)); } void DrawGizmos (Color col) { if (EditorApplication.isPlaying) return; Gizmos.color = col; Matrix4x4 mat = transform.localToWorldMatrix; foreach (Thingy t in things) { Gizmos.matrix = mat * t.matrix; Gizmos.DrawCube(t.mesh.bounds.center, t.mesh.bounds.size); } }   // Baking stuff: Copy in all the referenced objects into the scene on play or build [PostProcessScene(-2)] public static void OnPostprocessScene() { foreach (PrefabInstance pi in UnityEngine.Object.FindObjectsOfType (typeof (PrefabInstance)))      BakeInstance (pi); }   public static void BakeInstance (PrefabInstance pi) { if(!pi.prefab || !pi.enabled) return; pi.enabled = false; GameObject go = PrefabUtility.InstantiatePrefab(pi.prefab) as GameObject; Quaternion rot = go.transform.localRotation; Vector3 scale = go.transform.localScale; go.transform.parent = pi.transform; go.transform.localPosition = Vector3.zero; go.transform.localScale = scale; go.transform.localRotation = rot; pi.prefab = null; foreach (PrefabInstance childPi in go.GetComponentsInChildren<PrefabInstance>()) BakeInstance (childPi); }   #endif }

用法比较简单，比如我有两个Prefab，inside嵌入在Big里面。如下图所示，把PrefabInstance脚本挂在Big上，然后把inside拖入下方。

OK 无论怎么修改inside这个Prefab，当实例化Big的时候都能得到最新修改的Inside这个Prefab。

持续思考：

界面预览问题，就是我在布界面的时候，我需要把子集Prefab界面控件拖进来预览效果。如果用上述思路UI的Prefab就必须通过脚本自动生成。一份是预览用的也就是不需要脚本的，一份是只带脚本运行时动态生成的。在处理自动生成UIPrefab的时候可以利用tag 比如像这种需要内嵌的Prefab标记一个特殊的tag，在Editor下完成Prefab的导出。另外布界面的时候不需要绑定脚本，而上述脚本的绑定也应该由Editor导出Prefab的时候完成。

总之一切布界面的时候只操作Prefab不操作脚本。

最近造了个轮子可以批量替换prefab里的prefab，欢迎大家测试～  https://bitbucket.org/xuanyusong/prefab-replace

如果有更好的方法欢迎各位朋友在下面给我留言，谢谢。