using UnityEngine;
using System.Collections;
using System.Collections.Generic;public class AssetBundleManager
{public static AssetBundleManager Instace{get{if (_instace == null) _instace = new AssetBundleManager();return _instace;}}private static AssetBundleManager _instace = null;private AssetBundleManifest manifest = null;private Dictionary<string, AssetBundle> dicAssetBundle = new Dictionary<string, AssetBundle>();// filename : Assets全路径，比如Assets/Prefab/***.prefabpublic AssetBundle GetAssetBundle(string filePath){AssetBundle ab = null;dicAssetBundle.TryGetValue(AssetsNameToBundleName(filePath), out ab);return ab;}// 加载manifest，用来处理关联资源public void LoadManifest(){AssetBundle bundle = AssetBundle.LoadFromFile(MainifestFilePath());manifest = bundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");// 压缩包直接释放掉bundle.Unload(false);bundle = null;}// filename : Assets全路径，比如Assets/Prefab/***.prefabpublic AssetBundle Load(string filename){string bundleName = AssetsNameToBundleName(filename);if (dicAssetBundle.ContainsKey(bundleName)){return dicAssetBundle[bundleName];}
string[] dependence = manifest.GetAllDependencies(bundleName);for (int i = 0; i < dependence.Length; ++i){LoadInternal(dependence[i]);
        }return LoadInternal(bundleName);}// filename : Assets全路径，比如Assets/Prefab/***.prefabpublic IEnumerator LoadAsync(string filename){string bundleName = AssetsNameToBundleName(filename);if (dicAssetBundle.ContainsKey(bundleName)){yield break;}string[] dependence = manifest.GetAllDependencies(bundleName);for (int i = 0; i < dependence.Length; ++i){yield return LoadInternalAsync(dependence[i]);}yield return LoadInternalAsync(bundleName);}public void Unload(string filename, bool force = false){string bundleName = AssetsNameToBundleName(filename);AssetBundle ab = null;if (dicAssetBundle.TryGetValue(bundleName, out ab) == false) return;if (ab == null) return;ab.Unload(force);ab = null;dicAssetBundle.Remove(bundleName);}public void UnloadUnusedAssets(){Resources.UnloadUnusedAssets();System.GC.Collect();}public void Release(){foreach(var pair in dicAssetBundle){var bundle = pair.Value;if(bundle != null){bundle.Unload(true);bundle = null;}}dicAssetBundle.Clear();}private AssetBundle LoadInternal(string bundleName){if (dicAssetBundle.ContainsKey(bundleName)){return dicAssetBundle[bundleName];}AssetBundle bundle = AssetBundle.LoadFromFile(BundleNameToBundlePath(bundleName));dicAssetBundle.Add(bundleName, bundle);return bundle;}private IEnumerator LoadInternalAsync(string bundleName){if (dicAssetBundle.ContainsKey(bundleName)){yield break;}AssetBundleCreateRequest req = AssetBundle.LoadFromFileAsync(BundleNameToBundlePath(bundleName));yield return req;dicAssetBundle.Add(bundleName, req.assetBundle);}// 名字依赖于存放目录private string MainifestFilePath(){return Application.dataPath + "/StreamingAssets/StreamingAssets";}// Assets/Prefab/***.prefab --> assets.prefab.***.prefab.assetbundleprivate string AssetsNameToBundleName(string file){string f = file.Replace('/', '.');f = f.ToLower();f += ".assetbundle";return f;}// assets.prefab.***.prefab.assetbundle --> C:/***path***/assets.prefab.***.prefab.assetbundleprivate string BundleNameToBundlePath(string bundleFilename){return System.IO.Path.Combine(Application.dataPath + "/StreamingAssets/", bundleFilename);}}