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AssetBundle 技术文档

news 2026/3/26 20:00:05

1. 概述

AssetBundle 是 Unity 提供的一种资源打包与加载机制，用于将资源（模型、贴图、音频、Prefab 等）打包成二进制文件，在运行时按需加载。
主要用途：
- 减少首包体积。
- 按需加载资源，降低内存占用。
- 支持热更新（结合 PersistentDataPath）。

2. 资源路径对比

路径类型	特点	是否可写	常见用途
Resources/	打包进应用，运行时可用 `Resources.Load` 加载	❌	小型静态资源，快速加载
StreamingAssets/	原样拷贝进包，跨平台路径不同	❌	首包资源、配置文件
PersistentDataPath	运行时生成，可读写	✅	热更新资源、用户数据
Application.dataPath	项目数据目录	❌	调试用，不适合运行时加载

3. AssetBundle 管理器示例代码

下面是一个完整的 ABMgr 管理器，支持同步、异步、依赖加载和卸载。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;public class ABMgr : SingletonAutoMono<ABMgr>
{// 主包private AssetBundle mainAB = null;// 依赖包配置文件private AssetBundleManifest manifest = null;// 已加载的 AB 包缓存Dictionary<string, AssetBundle> abDic = new Dictionary<string, AssetBundle>();/// <summary>/// AB 包路径/// </summary>private string PathUrl => Application.streamingAssetsPath + "/";private string MainABName {get {
#if UNITY_IOSreturn "IOS";
#elif UNITY_ANDROIDreturn "Android";
#elsereturn "PC";
#endif}}// 加载 AB 包及依赖public void LoadAB(string abName) {if (mainAB == null) {mainAB = AssetBundle.LoadFromFile(PathUrl + MainABName);manifest = mainAB.LoadAsset<AssetBundleManifest>("AssetBundleManifest");}AssetBundle ab;string[] strs = manifest.GetAllDependencies(abName);for (int i = 0; i < strs.Length; i++) {if (!abDic.ContainsKey(strs[i])) {ab = AssetBundle.LoadFromFile(PathUrl + strs[i]);abDic.Add(strs[i], ab);}}if (!abDic.ContainsKey(abName)) {ab = AssetBundle.LoadFromFile(PathUrl + abName);abDic.Add(abName, ab);}}// 同步加载（不推荐）public Object LoadRes(string abName, string resName) {LoadAB(abName);Object obj = abDic[abName].LoadAsset(resName);return obj is GameObject ? Instantiate(obj) as GameObject : obj;}// 同步加载（指定类型）public Object LoadRes(string abName, string resName, System.Type type) {LoadAB(abName);Object obj = abDic[abName].LoadAsset(resName, type);return obj is GameObject ? Instantiate(obj) as GameObject : obj;}// 同步加载（泛型）public T LoadRes<T>(string abName, string resName) where T : Object {LoadAB(abName);T obj = abDic[abName].LoadAsset<T>(resName);return obj is GameObject ? Instantiate(obj) as T : obj;}// 异步加载（非泛型）public void LoadResAsync(string abName, string resName, UnityAction<Object> callBack) {StartCoroutine(ReallyLoadResAsync(abName, resName, callBack));}public IEnumerator ReallyLoadResAsync(string abName, string resName, UnityAction<Object> callBack) {LoadAB(abName);AssetBundleRequest abr = abDic[abName].LoadAssetAsync(resName);yield return abr;callBack(abr.asset is GameObject ? Instantiate(abr.asset) : abr.asset);}// 异步加载（指定类型）public void LoadResAsync(string abName, string resName, System.Type type, UnityAction<Object> callBack) {StartCoroutine(ReallyLoadResAsync(abName, resName, callBack));}public IEnumerator ReallyLoadResAsync(string abName, string resName, System.Type type, UnityAction<Object> callBack) {LoadAB(abName);AssetBundleRequest abr = abDic[abName].LoadAssetAsync(resName, type);yield return abr;callBack(abr.asset is GameObject ? Instantiate(abr.asset) : abr.asset);}// 异步加载（泛型）public void LoadResAsync<T>(string abName, string resName, UnityAction<T> callBack) where T : Object {StartCoroutine(ReallyLoadResAsync<T>(abName, resName, callBack));}public IEnumerator ReallyLoadResAsync<T>(string abName, string resName, UnityAction<T> callBack) where T : Object {LoadAB(abName);AssetBundleRequest abr = abDic[abName].LoadAssetAsync<T>(resName);yield return abr;callBack(abr.asset is GameObject ? Instantiate(abr.asset) as T : abr.asset as T);}// 卸载单个包public void UnLoad(string abName) {if (abDic.ContainsKey(abName)) {abDic[abName].Unload(false);abDic.Remove(abName);}}// 卸载所有包public void ClearAB() {AssetBundle.UnloadAllAssetBundles(false);abDic.Clear();mainAB = null;manifest = null;}
}