unity

1.AB包的依赖问题

例如一个Prefab被添加到了AB包中，该包会默认添加这个预设体带有的材质等，然而如果你手动把相关的材质添加到了另外的AB包中，此时该材质就不会添加到预设体的AB包中（可能是出于性能考虑机制），则一定要引用预设体对应的包和材质所对应的包，否则会出现材质错误。

然而显而易见的是当这个预设体的引用来自各个不同的AB包中，那么一条一条引入包的代码就会显得很冗余。所以引入了下面这个方法。

通过给定的API得到所有依赖的信息，然后用一个string数组存储这些依赖包的名字，通过遍历依赖名字数组导入所有的依赖。

AssetBundle abMain = AssetBundle.LoadFromFile (Application.streamingAssetsPath + "/" + "PC");
// 加载主包中的固定文件
AssetBundleManifest abManifest = abMain.LoadAsset<AssetBundleManifest>("AssetBundleManifest");
// 从固定文件中 得到依赖信息
string [] strs = abManifest.GetAllDependencies ("model");
// 得到了 依赖包的名字
for (int i = 0; i < strs.Length; i++)
{AssetBundle.LoadFromFile (Application.streamingAssetsPath+ "/" + strs [i]);
}

这种方法不能对一个AB包中的预设体进行区分，例如A刚需EF包，B刚需OL包，
然而我项目中只使用了A，然而在检查依赖的时候会一同加载不被需要的OL包。

2.AB包资源管理器

先导：饿汉模式与懒汉模式

饿汉模式

在类建立之初就创建一个只读的对象，确保唯一。

using UnityEngine;public class EagerSingleton : MonoBehaviour
{// 静态字段，用于存储单例实例public static EagerSingleton instance;private void Awake(){// 在Awake方法中进行实例的初始化if (instance == null){instance = this;// 确保单例对象在场景切换时不会被销毁DontDestroyOnLoad(gameObject);}else{// 如果已经存在实例，则销毁当前对象Destroy(gameObject);}}
}

懒汉模式

引用自：博主YY-nb直达
确保只有在类的内部才能实例化，外部只能调用Instance方法。
使用lock确保在同一时间内只有一个进程在执行创建单例。
如果后续还有访问这个单例的，直接返回这个单例，不要再继续加锁了，影响性能。

public class Singleton
{private static Singleton instance;private static readonly object locker = new object();private Singleton(){}public static Singleton Instance{get{if (instance == null){lock (locker){if (instance == null)instance = new Singleton();                    }}return instance;}       }
}

AB资源管理器主代码

using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;public class AssetBundleManager : MonoBehaviour
{public static AssetBundleManager Instance;private Dictionary<string, AssetBundle> abDic;private AssetBundle mainAB = null;private AssetBundleManifest mainfest = null;public string abUrl { get; private set; }public string mainAbName { get; private set; }private void Awake(){if (Instance == null){Instance = this;DontDestroyOnLoad(gameObject);}else if(Instance != this){Destroy(gameObject);}}private void Start(){abDic = new Dictionary<string, AssetBundle>();abUrl = Application.streamingAssetsPath + "/";mainAbName = "PC";}//加载依赖public void LoadDepends(string abName){//获取主包if(mainAB == null){mainAB = AssetBundle.LoadFromFile(abUrl + mainAbName);        //固定语法 获取AB包配置文件mainfest = mainAB.LoadAsset<AssetBundleManifest>("AssetBundleManifest");}string[] temp = mainfest.GetAllDependencies(abName);//主包API获取小包的依赖for(int i = 0; i < temp.Length; i++){if (!abDic.ContainsKey(temp[i])){AssetBundle tempab = AssetBundle.LoadFromFile(abUrl + temp[i]);//某个小包 依赖了这么多小包abDic.Add(temp[i], tempab);}else{Debug.Log("again");}}if (!abDic.ContainsKey(abName)){AssetBundle ab = AssetBundle.LoadFromFile(abUrl + abName);abDic.Add(abName, ab);}else{Debug.Log("again");}}// 同步加载public T LoadRes<T>(string abName, string resName) where T : Object{Debug.Log("YSe");LoadDepends(abName);T res = abDic[abName].LoadAsset<T>(resName);return res;}// 异步加载// 异步加载依赖public IEnumerator LoadDependsAsync(string abName){// 获取主包if (mainAB == null){AssetBundleCreateRequest mainABRequest = AssetBundle.LoadFromFileAsync(abUrl + mainAbName);yield return mainABRequest;mainAB = mainABRequest.assetBundle;mainfest = mainAB.LoadAsset<AssetBundleManifest>("AssetBundleManifest");}//只要涉及获取等待的任务 都需要一个yield returnstring[] temp = mainfest.GetAllDependencies(abName);for (int i = 0; i < temp.Length; i++){if (!abDic.ContainsKey(temp[i])){AssetBundleCreateRequest tempAbRequest = AssetBundle.LoadFromFileAsync(abUrl + temp[i]);yield return tempAbRequest;AssetBundle tempab = tempAbRequest.assetBundle;abDic.Add(temp[i], tempab);}else{Debug.Log("again");}}if (!abDic.ContainsKey(abName)){AssetBundleCreateRequest abRequest = AssetBundle.LoadFromFileAsync(abUrl + abName);yield return abRequest;AssetBundle ab = abRequest.assetBundle;abDic.Add(abName, ab);}else{Debug.Log("again");}}// 异步加载资源public IEnumerator LoadResAsync<T>(string abName, string resName, System.Action<T> onComplete) where T : Object{yield return StartCoroutine(LoadDependsAsync(abName));AssetBundleRequest request = abDic[abName].LoadAssetAsync<T>(resName);yield return request;T res = abDic[abName].LoadAsset<T>(resName);onComplete?.Invoke(res);}// 卸载单个包public void UnLoad(string abName){abDic[abName].Unload(false);abDic.Remove(abName);}// 卸载所有包public void UnLoadAll(){AssetBundle.UnloadAllAssetBundles(false);abDic.Clear();mainAB = null;mainfest = null;}
}

TEST脚本

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class Test : MonoBehaviour
{// Start is called before the first frame updatevoid Start(){//同步GameObject gameObject = AssetBundleManager.Instance.LoadRes<GameObject>("model", "Cube");Instantiate(gameObject,Vector3.up,Quaternion.identity);GameObject gameObject2 = AssetBundleManager.Instance.LoadRes<GameObject>("model", "Cube");Instantiate(gameObject2, Vector3.down, Quaternion.identity);//异步StartCoroutine(AssetBundleManager.Instance.LoadResAsync<GameObject>("model", "Cube", OnAssetLoaded));}//根据传出类型的不同 编写不同的OnXXX函数，然后订阅此函数private void OnAssetLoaded(GameObject loadedAsset){if (loadedAsset != null){// 资源加载成功，实例化该资源Instantiate(loadedAsset);Debug.Log("资源加载并实例化成功！");}else{Debug.LogError("资源加载失败！");}}// Update is called once per framevoid Update(){}
}