Unity逻辑热更新

声明：
原博链接： http://blog.csdn.net/janeky/article/details/17652021
只是把自己研究实践的过程记录下来

先直接上代码：两个类，一个检测资源更新，有更新则下载到本地（ResUpdate），一个是逻辑热更新（LogicUpdate）
一、资源对比更新并下载。
资源是否更新了是通过比对服务器与客户端的 资源版本表： version.txt
该文本文档内容为：

Cube.assetbundle,78a6cd06388449d16aea5f6eae395abf
hotab.assetbundle,7ae97ca818017fcb7879c56d6a350676
Sphere.assetbundle,c58c93cffdc73669e10d3f449e1fa29c
version.txt,f864be607802fcc71b622d7ea5383c8f

工具地址：https://github.com/kenro/File_Md5_Generator

public class ResUpdate : MonoBehaviour {
    public static readonly string VERSION_FILE="version.txt";
    public static readonly string LOCAL_RES_URL="file://"+Application.dataPath+"/Res/";
    public static readonly string SERVER_RES_URL = "file:///F:/HotUpdateTest/ab/";
    public static readonly string LOCAL_RES_PATH=Application.dataPath+"/Res/";

    private Dictionary<string,string> LocalResVersion;
    private Dictionary<string,string> ServerResVersion;
    private List<string> NeedDownFiles;
    private bool NeedUpdateLocalVersionFile = false;

    // Use this for initialization
    void Start () {

        LocalResVersion = new Dictionary<string, string> ();
        ServerResVersion = new Dictionary<string, string> ();
        NeedDownFiles = new List<string> ();

        //加载本地version配置
        StartCoroutine(DownLoad(LOCAL_RES_URL + VERSION_FILE,
            delegate(WWW localVersion)
            {
                //保存本地的version
                ParseVersionFile(localVersion.text, LocalResVersion);
                StartCoroutine(DownLoad(SERVER_RES_URL + VERSION_FILE,
                    delegate(WWW serverVersion)
                    {
                        //保存服务端version
                        ParseVersionFile(serverVersion.text, ServerResVersion);
                        //对比本地和服务端版本
                        CompareVersion();
                        //加载需要更新的资源
                        DownLoadRes();
                    }));
            }));
    }  
    
    /// <summary>
    /// 保存version
    /// </summary>
    /// <param name="content"></param>
    /// <param name="dict"></param>
    private void ParseVersionFile(string content,Dictionary<string,string> dict)
    {
        if (content==null||content.Length==0)
        {
            return;
        }

        string[] items = content.Split(new char[] { ‘\n‘ });
        foreach (string item in items)
        {
            string[] info = item.Split(new char[] { ‘,‘ });
            if (info!=null&&info.Length==2)
            {
                dict.Add(info[0], info[1]);
            }
        }
    }

    /// <summary>
    /// 对比本地和服务端版本
    /// </summary>
    private void CompareVersion()
    {
        foreach (var version in ServerResVersion)
        {
            string fileName = version.Key;
            string serverMd5 = version.Value;
            //新增的资源
            if (!LocalResVersion.ContainsKey(fileName))
            {
                NeedDownFiles.Add(fileName);
            }
            else
            {
                //需要替换的资源
                string localMd5;
                //使用安全的获取方式，即：获取失败就直接替换资源
                LocalResVersion.TryGetValue(fileName, out localMd5);
                if (!serverMd5.Equals(localMd5))
                {
                    NeedDownFiles.Add(fileName);
                }
            }
            //本次有更新，同时更新本地的version.tex
            NeedUpdateLocalVersionFile = NeedDownFiles.Count > 0;
        }
    }


    /// <summary>
    /// 加载需要更新的资源
    /// </summary>
    private void DownLoadRes()
    {
        if (NeedDownFiles.Count==0)
        {
            UpdateLocalVersionFile();
            return;
        }

        string file = NeedDownFiles[0];
        NeedDownFiles.RemoveAt(0);

        StartCoroutine(DownLoad(SERVER_RES_URL + file, delegate(WWW w)
        {
            //将下载的资源替换本地的资源
            ReplaceLocalRes(file, w.bytes);
            DownLoadRes();
        }));
    }

    /// <summary>
    /// 更新本地的version配置
    /// </summary>
    private void UpdateLocalVersionFile()
    {
        if (NeedUpdateLocalVersionFile)
        {
            StringBuilder versions = new StringBuilder();
            foreach (var item in ServerResVersion)
            {
                versions.Append(item.Key).Append(",").Append(item.Value).Append("\n");
            }
            FileStream stream = new FileStream(LOCAL_RES_PATH + VERSION_FILE, FileMode.Create);
            byte[] data = Encoding.UTF8.GetBytes(versions.ToString());
            stream.Write(data, 0, data.Length);
            //这里可能是多余的，Flush本来是在没有Close的时候也会
            //将缓存中的数据写入到文件中
            //但是这里紧接着下面就是Close
            stream.Flush();  
            stream.Close();
        }
        // 测试用：显示加载的资源包 
        StartCoroutine(Show()); 
    }

    /// <summary>
    /// 测试用：显示加载的资源包
    /// </summary>
    /// <returns></returns>
    private IEnumerator Show()
    {
        WWW asset = new WWW(LOCAL_RES_URL + "Sphere.assetbundle");
        yield return asset;
        AssetBundle bundle = asset.assetBundle;
        Instantiate(bundle.LoadAsset("Sphere"));
        ///这是U3D没有处理好的一个环节。在WWW加载资源完毕后，对资源进行instantiate后，对其资源进行unload,这时问题就发生 了，instantiate处理渲染需要一定的时间，虽然很短，但也是需要1，2帧的时间。此时进行unload会对资源渲染造成影响，以至于没有贴图或 者等等问题发生。
        //解决办法：
        //自己写个时间等待代码，最好不要用WaitForSeconds，U3D的API，这个东西很撮，恶心死我了。。。
        //我估计它这个类写的有问题，检查了好长时间，最后还是自己写了几行代码来替换这个类，解决了问题。
        //等待个0.5秒到1秒之后再进行Unload。这样就不会出现instantiate渲染中就运行unload的情况了。
        yield return null;
        bundle.Unload(false);
    }
    
    /// <summary>
    /// 替换本地资源
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="data"></param>
    private void ReplaceLocalRes(string fileName,byte[] data)
    {
        string filePath = LOCAL_RES_PATH + fileName;
        FileStream stream = new FileStream(LOCAL_RES_PATH + fileName, FileMode.Create);
        stream.Write(data, 0, data.Length);
        stream.Flush();
        stream.Close();
    }

    /// <summary>
    /// 加载资源（服务器和本地）
    /// </summary>
    /// <param name="url"></param>
    /// <param name="finishFun"></param>
    /// <returns></returns>
    private IEnumerator DownLoad(string url,HandleFinishDownload finishFun)
    {
        using (WWW www = new WWW(url))
        {
            yield return www;
            if (finishFun != null)
            {
                finishFun(www);
            }
        }
    }

    public delegate void HandleFinishDownload(WWW www);
}


二、逻辑热更新
将逻辑代码生成Dll，将其打包成assetbundl前将其后缀改为.bytes，不然会报错

public class LogicUpdate : MonoBehaviour
{
    private static readonly string DLL_URL = "file:///D:/HostServer/Blood/AssetBundle/test.assetbundle";

    void Start()
    {
        StartCoroutine(loadDllScript());
    }

    private IEnumerator loadDllScript()
    {
        WWW www = new WWW(DLL_URL);
        yield return www;
        AssetBundle bundle = www.assetBundle;
        TextAsset asset = bundle.LoadAsset("test", typeof(TextAsset)) as TextAsset;

        System.Reflection.Assembly assembly = System.Reflection.Assembly.Load(asset.bytes);
        Type script1 = assembly.GetType("Script");
        GameObject obj = new GameObject();
        obj.AddComponent(script1);

        //Type script2 = assembly.GetType("Script2");
        //obj.AddComponent(script2);
    }