最近项目遇到个极为蛋疼的需求，因为某SDK不支持新版本,Unity需要葱2019降为2018. 2018导入2019的工程后，Unity自带的大量脚本丢失引用，一时头秃。

最后只能研究了下手动以文本方式打开prefab，对比新旧版本Unity脚本的FileID和GUID字段，写个脚本遍历工程中所有prefab，进行替换。

关于查看丢失引用的情况，推荐Maintainer插件，非常好用 https://assetstore.unity.com/packages/tools/utilities/maintainer-32199?locale=zh-CN

关于FileID和GUID可以参考这篇博文https://www.cnblogs.com/CodeGize/p/8697227.html

using System.Collections.Generic;
using System.IO;
using UnityEditor;
using UnityEngine;public class ProcessUnityVersion
{public static Dictionary<string, string> replaceDict = new Dictionary<string, string>(){{"m_Script: {fileID: 11500000, guid: 5f7201a12d95ffc409449d95f23cf332, type: 3}", "m_Script: {fileID: 708705254, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 3245ec927659c4140ac4f8d17403cc18, type: 3}", "m_Script: {fileID: 1741964061, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: fe87c0e1cc204ed48ad3b37840f39efc, type: 3}", "m_Script: {fileID: -765806418, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 0cd44c1031e13a943bb63640046fad76, type: 3}", "m_Script: {fileID: 1980459831, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: dc42784cf147c0c48a680349fa168899, type: 3}", "m_Script: {fileID: 1301386320, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 31a19414c41e5ae4aae2af33fee712f6, type: 3}", "m_Script: {fileID: -1200242548, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 1392445389, guid: f70555f144d8491a825f0804e09c671c, type: 3}", "m_Script: {fileID: 11500000, guid: a65f502c9af7751458beffa2a6c253c3, type: 3}"},{"m_Script: {fileID: 11500000, guid: 8a8695521f0d02e499659fee002a26c2, type: 3}", "m_Script: {fileID: -2095666955, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 1344c3c82d62a2a41a3576d8abb8e3ea, type: 3}", "m_Script: {fileID: -98529514, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 4e29b1a8efbd4b44bb3f3716e73f07ff, type: 3}", "m_Script: {fileID: 1392445389, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: e19747de3f5aca642ab2be37e372fb86, type: 3}","m_Script: {fileID: -900027084, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 306cc8c2b49d7114eaa3623786fc2126, type: 3}","m_Script: {fileID: 1679637790, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{" m_Script: {fileID: 11500000, guid: 1aa08ab6e0800fa44ae55d278d1423e3, type: 3}","m_Script: {fileID: 1367256648, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 30649d3a9faa99c48a7b1166b86bf2a0, type: 3}","m_Script: {fileID: -405508275, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 86710e43de46f6f4bac7c8e50813a599, type: 3}","m_Script: {fileID: -1254083943, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 67db9e8f0e2ae9c40bc1e2b64352a6b4, type: 3}","m_Script: {fileID: -113659843, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 59f8146938fff824cb5fd77236b75775, type: 3}","m_Script: {fileID: 1297475563, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: d199490a83bb2b844b9695cbf13b01ef, type: 3}","m_Script: {fileID: 575553740, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: 9085046f02f69544eb97fd06b6048fe2, type: 3}","m_Script: {fileID: 2109663825, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},{"m_Script: {fileID: 11500000, guid: d0b148fe25e99eb48b9724523833bab1, type: 3}","m_Script: {fileID: -1862395651, guid: f70555f144d8491a825f0804e09c671c, type: 3}"},};[MenuItem("Tool/替换低版本引用")]public static void Process(){ProcessAllPrefabs();}private static void ProcessAllPrefabs(){List<GameObject> prefabs = new List<GameObject>();var resourcesPath = Application.dataPath;var absolutePaths = System.IO.Directory.GetFiles(resourcesPath, "*.prefab", System.IO.SearchOption.AllDirectories);for (int i = 0; i < absolutePaths.Length; i++){Debug.Log("prefab name: " + absolutePaths[i]);foreach (var VARIABLE in replaceDict){ReplaceValue(absolutePaths[i],VARIABLE.Key, VARIABLE.Value );}EditorUtility.DisplayProgressBar("处理预制体……", "处理预制体中……", (float)i/absolutePaths.Length);}EditorUtility.ClearProgressBar();}/// <summary>/// 替换值/// </summary>/// <param name="strFilePath">txt等文件的路径</param>private static void ReplaceValue(string strFilePath, string oldLine, string newLine){if (File.Exists(strFilePath)){string[] lines = System.IO.File.ReadAllLines(strFilePath);for (int i = 0; i < lines.Length; i++){lines[i] = lines[i].Replace(oldLine, newLine);}File.WriteAllLines(strFilePath, lines);}}
}