[Unity热更新]unity5中的assetbundle

参考链接：
http://liweizhaolili.blog.163.com/blog/static/16230744201541410275298/ http://liweizhaolili.blog.163.com/blog/static/162307442015282017852/ http://itfish.net/article/35172.html
简单的说，unity打包时，会为每个文件创建一个.unity3d文件和.manifest文件。其中.unity3d文件包含了被打包的资源，.manifest文件记录该资源的依赖关系。然后所有.manifest文件汇总到一个总的依赖文件中，在游戏最开始运行的时候需要加载这个总的依赖文件，然后加载assetbundle的时候，从中获取到依赖关系来加载依赖。在操作中，实际操作的还是.unity3d文件，而.manifest文件主要的作用就是查看依赖关系。
总结起来，就是四步：
1.为assetbundle起名字，并打包
2.加载总的依赖文件
3.加载assetbundle的依赖文件
4.加载assetbundle



1.命名并打包
using UnityEngine;
using System.Collections;
using UnityEditor;
using System.IO;

public class CreateAssetBundle : Editor {

[MenuItem("Tool/SetAssetBundleNameExtension")]
static void SetBundleName()
{
#region 设置资源的AssetBundle的名称和文件扩展名
UnityEngine.Object[] selects = Selection.objects;
foreach (UnityEngine.Object selected in selects)
{
string path = AssetDatabase.GetAssetPath(selected);
AssetImporter asset = AssetImporter.GetAtPath(path);
asset.assetBundleName = selected.name; //设置Bundle文件的名称
asset.assetBundleVariant = "unity3d";//设置Bundle文件的扩展名
asset.SaveAndReimport();
}
AssetDatabase.Refresh();
#endregion
}

[MenuItem("Tool/BuildAll")]
static void Build()
{
string path = Application.dataPath + "/AB";
if(!Directory.Exists(path)) Directory.CreateDirectory(path);
BuildPipeline.BuildAssetBundles(path);
AssetDatabase.Refresh();
}

}

或者也可以这样：

using UnityEngine;
using System.Collections;
using UnityEditor;

public class AutoSetAssetBundleName : AssetPostprocessor {

static void OnPostprocessAllAssets (string[] importedAssets, string[] deletedAssets, string[] movedAssets, string[] movedFromAssetPaths)
{
foreach (var str in importedAssets)
{
//Debug.Log("Reimported Asset: " + str);
if(!str.EndsWith(".cs"))
{
AssetImporter importer = AssetImporter.GetAtPath(str);
importer.assetBundleName = str;
}
}
foreach (var str in deletedAssets)
{
//Debug.Log("Deleted Asset: " + str);
if(!str.EndsWith(".cs"))
{
AssetImporter importer = AssetImporter.GetAtPath(str);
importer.assetBundleName = str;
}
}

for (var i=0; i<movedAssets.Length; i++)
{
//Debug.Log("Moved Asset: " + movedAssets[i] + " from: " + movedFromAssetPaths[i]);
}
}
}

2.加载
using UnityEngine;
using System.Collections;

public class AssetbBundleManager : MonoSingletion<AssetbBundleManager> {

public delegate void OnLoadAssetbBundleFinish(AssetBundle assetBundle, string nameWithoutExtension);

/// <summary>
///
/// </summary>
/// <param name="assetBundleDir">Assetbundle的文件夹 </param>
/// <param name="assetBundleName">要加载的AssetBundle的名字</param>
public void Load(string assetBundleDir, string assetBundleName, OnLoadAssetbBundleFinish onLoadFinish)
{
StartCoroutine(LoadIEnumerator(assetBundleDir, assetBundleName, onLoadFinish));
}

private IEnumerator LoadIEnumerator(string assetBundleDir, string assetBundleName, OnLoadAssetbBundleFinish onLoadFinish)
{
//首先加载总Manifest文件;
WWW wwwAll = new WWW(assetBundleDir + "AB");
yield return wwwAll;
if (!string.IsNullOrEmpty(wwwAll.error))
{
Debug.LogError(wwwAll.error);
}
else
{
AssetBundle ab = wwwAll.assetBundle;
AssetBundleManifest manifest = (AssetBundleManifest)ab.LoadAsset("AssetBundleManifest");
ab.Unload(false);

//获取依赖文件列表;
string[] depends = manifest.GetAllDependencies(assetBundleName);
AssetBundle[] dependsAssetBundle = new AssetBundle[depends.Length];

for (int index = 0; index < depends.Length; index++)
{
//加载所有的依赖文件;
WWW dwww = WWW.LoadFromCacheOrDownload(assetBundleDir + depends[index], 0);
yield return dwww;
dependsAssetBundle[index] = dwww.assetBundle;
}

//加载我们需要的文件;
WWW www = new WWW(assetBundleDir + assetBundleName);
yield return www;
if (!string.IsNullOrEmpty(www.error))
{
Debug.LogError(www.error);
}
else
{
string name = assetBundleName.Substring(0, assetBundleName.IndexOf("."));
AssetBundle assetBundle = www.assetBundle;
onLoadFinish(assetBundle, name);

assetBundle.Unload(false);
}

//卸载依赖文件的包
for (int index = 0; index < depends.Length; index++)
{
dependsAssetBundle[index].Unload(false);
}
}
}

public string GetString(AssetBundle assetBundle, string name)
{
return assetBundle.LoadAsset<TextAsset>(name).ToString();
}

public GameObject GetGameObject(AssetBundle assetBundle, string name)
{
return assetBundle.LoadAsset<GameObject>(name);
}

}

using UnityEngine;
using System.Collections;
using LuaInterface;

public class LoadAssetbBundle : MonoBehaviour {

void Start()
{
string dir = @"file:///" + Application.persistentDataPath + "/";
//Debug.Log(dir);

AssetbBundleManager.Instance.Load(dir, "newuluascript.unity3d",
(ab, name) =>
{
string content = AssetbBundleManager.Instance.GetString(ab, name);
LuaScriptMgr lua = new LuaScriptMgr();
lua.Start();
lua.DoString(@content);
});
}

}