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
}
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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。
如果有更好的方法欢迎各位朋友在下面给我留言，谢谢。