工具类封装
通过上文中对AB包加载API的了解和简单使用，对AB包资源加载的几种方法进行封装，将其写入单例类中，如代码展示。
确保每个AB资源包只加载一次：
在LoadAssetBundleManager 单例工具类中，首先提供基本的AB包及其AB包依赖包的加载方法，为保持AssetBundle只加载一次，使用DIctionary键值对来记录已经加载出的AB资源。
主包路径的灵活获取：
加载主包路径的获取，采用宏来对不同的打包平台来选择对应的主包名称。（可自行定义使用）
依赖包的加载：
通过加载主包中的AssetBundleManifest 来获取目标AB包的依赖AB包名称，根据名称进行逐个加载。
加载方法有异步和同步两种：
异步加载是在AB包获取之后进行的资源的异步加载，和同步加载一样有对加载函数进行3此重载。分别为根据名称加载，
泛型加载（C#中使用方便），根据类型加载（供Lua调用）。
卸载方法的实现：单个AB资源包卸载和所有资源包卸载两种方式。
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;namespace BaseFramework
{/// <summary>/// 加载AssetBundle工具类 单例 /// </summary>public class LoadAssetBundleManager: SingletonAutoMono<LoadAssetBundleManager>{//主AB包 private AssetBundle mainAssetBundle = null;//包体依赖manifest private AssetBundleManifest assetBundleManifest = null;//防止AB包重复加载 对已经加载的AB包存储private Dictionary<string, AssetBundle> assetBundlesDic = new Dictionary<string, AssetBundle>();//加载路径private string pathAssetBundle{get{return Application.streamingAssetsPath + "/";}}//主包名称private string mainAssetBundleName{get{
#if UnITY_IOSreturn "IOS";
#elif UNITY_ANDROIDreturn "Android";
#elsereturn "StandaloneWindows";
#endif}}/// <summary>/// 根据名称加载AB包 也会检查相关依赖包 进行加载/// </summary>/// <param name="assetBundleName">AB包的名称</param>public void LoadAssetBundle(string assetBundleName){if (!assetBundlesDic.ContainsKey(assetBundleName)){AssetBundle resAssetBundle = AssetBundle.LoadFromFile(pathAssetBundle+assetBundleName);assetBundlesDic.Add(assetBundleName,resAssetBundle);}//加载主资源包 从主资源包中获取对manifestif (mainAssetBundle == null){mainAssetBundle = AssetBundle.LoadFromFile(pathAssetBundle + mainAssetBundleName);assetBundleManifest = mainAssetBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");}//加载目标资源包的依赖ABstring[] dependencies = assetBundleManifest.GetAllDependencies(assetBundleName);foreach (var dependency in dependencies){AssetBundle currentAB = null;if (!assetBundlesDic.ContainsKey(dependency)){//加载依赖的ab包currentAB = AssetBundle.LoadFromFile(pathAssetBundle + dependency); assetBundlesDic.Add(dependency,currentAB);}}}/// <summary>/// 从AB包中获取具体资源/// </summary>/// <param name="abName">AB包名称</param>/// <param name="resName">资源名称</param>/// <returns>Object资源</returns>public Object LoadResource(string abName, string resName){LoadAssetBundle(abName);Object resObj = null;resObj = assetBundlesDic[abName].LoadAsset(resName);return resObj;}/// <summary>/// 泛型方法重载/// </summary>public T LoadResource<T>(string abName, string resName) where T:Object{LoadAssetBundle(abName);T res = assetBundlesDic[abName].LoadAsset<T>(resName);return res;}/// <summary>/// 根据资源类型重载方法/// </summary>public Object LoadResource(string abName, string resName, System.Type type){LoadAssetBundle(abName);Object obj = assetBundlesDic[abName].LoadAsset(resName, type);return obj;}//--------------------------------------------------------//同步加载的AB包 异步加载res资源public void LoadResourceAsync(string abName, string resName, UnityAction<Object> callback){StartCoroutine(LoadResourceIEn(abName, resName, callback));}//异步加载协程private IEnumerator LoadResourceIEn(string abName, string resName, UnityAction<Object> callback){LoadAssetBundle(abName);AssetBundleRequest request = assetBundlesDic[abName].LoadAssetAsync(resName);yield return request;callback(request.asset);}//根据泛型来异步加资源public void LoadResourceAsync<T>(string abName, string resName, UnityAction<Object> callback) where T : Object{StartCoroutine(LoadResourceIEn<T>(abName, resName, callback));}//异步加载协程private IEnumerator LoadResourceIEn<T>(string abName, string resName, UnityAction<Object> callback) where T :Object{LoadAssetBundle(abName);AssetBundleRequest request = assetBundlesDic[abName].LoadAssetAsync<T>(resName);yield return request;callback(request.asset);}//根据res类型异步加载资源//根据泛型来异步加资源public void LoadResourceAsync(string abName, string resName, System.Type type,UnityAction<Object> callback) {StartCoroutine(LoadResourceIEn(abName, resName, type, callback));}//异步加载协程private IEnumerator LoadResourceIEn(string abName, string resName, System.Type type, UnityAction<Object> callback) {LoadAssetBundle(abName);AssetBundleRequest request = assetBundlesDic[abName].LoadAssetAsync(resName,type);yield return request;callback(request.asset);}//资源包的卸载public void UnLoadAssetBundle(string abName){if (assetBundlesDic.ContainsKey(abName)){assetBundlesDic[abName].Unload(false);assetBundlesDic.Remove(abName);}}//卸载所有加载的资源包public void UnLoadAllAssetBundle(){AssetBundle.UnloadAllAssetBundles(false);assetBundlesDic.Clear();mainAssetBundle = null;assetBundleManifest = null;}}
}
该Manager继承的单例脚本：
using UnityEngine;namespace BaseFramework
{public class SingletonAutoMono<T> : MonoBehaviour where T : MonoBehaviour{private static T instance;public static T Instance(){if (instance == null){GameObject gameObject = new GameObject();gameObject.name = typeof(T).ToString();DontDestroyOnLoad(gameObject);instance = gameObject.AddComponent<T>();}return instance;}}
}
在测试脚本中我们使用6种不同的加载方式进行cube的加载，完成方法测试。
//测试使用工具类加载Object cube = LoadAssetBundleManager.Instance().LoadResource("model", "cube");if (cube is GameObject){GameObject cube1 = cube as GameObject;cube1.transform.position = Vector3.up;Instantiate(cube1);}//异步加载LoadAssetBundleManager.Instance().LoadResourceAsync("model", "cube", (obj) =>{GameObject cube1 = obj as GameObject;cube1.transform.position = new Vector3(0,1.5f,0);Instantiate(cube1);});//重新测试//使用泛型GameObject cube2 = LoadAssetBundleManager.Instance().LoadResource<GameObject>("model", "cube");cube2.transform.position = Vector3.left;Instantiate(cube2);LoadAssetBundleManager.Instance().LoadResourceAsync<GameObject>("model", "cube", (obj) =>{GameObject cube1 = obj as GameObject;cube1.transform.position = Vector3.right;Instantiate(cube1);});//通过类型加载测试GameObject cube3 = LoadAssetBundleManager.Instance().LoadResource("model", "cube",typeof(GameObject)) as GameObject;cube3.transform.position = new Vector3(0,-1.5f,0);Instantiate(cube3);LoadAssetBundleManager.Instance().LoadResourceAsync("model", "cube",typeof(GameObject), (obj) =>{GameObject cube1 = obj as GameObject;cube1.transform.position = Vector3.zero;Instantiate(cube1);});LoadAssetBundleManager.Instance().UnLoadAllAssetBundle();
