【Unity3d】【项目学习心得】从资源服务器下载资源(三)

上一篇我们分析了 从资源服务器下载资源(二) 接下来我们继续分析 LoadManager类。

当我们的任务下载完成后，我们需要对任务的委托进行回调到调用对象。

我们初步加入的委托有 complete、process、error ，接下来分别对这三个委托写相应的回调。

/// <summary>
    ///  下载错误回调
    /// </summary>
    public void ErrorDelegateHandle(LoadRequest request) {
        if (request.errorFunction != null) {
            int count = request.errorFunction.GetInvocationList().GetLength(0);
            for (int i = 0; i < count; i++) {
                LoadRequest.ErrorDelegate errorFunc = (LoadRequest.ErrorDelegate)request.errorFunction.GetInvocationList()[i];
                try {
                    errorFunc.Invoke(request);
                } catch (Exception e) {
                    Debug.LogWarning("exception:" + e.Message);
                }
            }
        }
    }

    /// <summary>
    ///  下载进度回调
    /// </summary>
    public void ProcessDelegateHandle(LoadRequest request) {
        if (request.processFunction != null) {
            int count = request.processFunction.GetInvocationList().GetLength(0);
            for (int i = 0; i < count; i++) {
                LoadRequest.ProcessDelegate processFunc = (LoadRequest.ProcessDelegate)request.processFunction.GetInvocationList()[i];
                try {
                    processFunc.Invoke(request.wwwObject.progress, request.wwwObject.bytesDownloaded);
                } catch (Exception e) {
                    Debug.LogWarning("exception:" + e.Message);
                }
            }
        }
    }

    /// <summary>
    ///  任务下载完成回调
    /// </summary>
    /// <param name="request"></param>
    /// <param name="param"></param>
    public void CompleteDelegateHandle(LoadRequest request, LoadParam param) {
        if (request.completeFunction != null) {
            int count = request.completeFunction.GetInvocationList().GetLength(0);
            for (int i = 0; i < count; i++) {
                if (i < request.customParams.Count) {
                    param.param = request.customParams[i];
                }
                LoadRequest.DownCompleteDelegate completeFunc = (LoadRequest.DownCompleteDelegate)request.completeFunction.GetInvocationList()[i];
                try {
                    completeFunc.Invoke(param);
                } catch (Exception exception) {
                    Debug.LogWarning("exception:" + exception.Message);
                }
            }
        }
    }

1. 在上面我们注意到有一个陌生的类 LoadParam. 这个类是用来做什么的呢？

很简单，因为我们下载完成后会进行存储所有的下载结果，方便后续下载相同资源时可以马上调用。所以我们需要专门的对象来存放。

我们把所有类型写到一个类里面，然后标注好该对象的对应URL、filetype。

如下：

/**
 * 任务下载的资源
 * create by chensh 2014.10.27 10:35
 */

using UnityEngine;
using System.Collections;

namespace AssemblyCSharp {
    public class LoadParam {
        // 加载的文件类型
        public string fileType;
        // 加载的路径
        public string url;

        // 自定义参数
        public object param = null;
        // 图片
        public Texture2D texture2D;
        // 文本
        public string text = "";
        // unity3d格式文件，目前针对场景打包的unity3d格式文件
        public AssetBundle assetBundle = null;
        // json文件
        public string jsonData;
        // 二进制文件
        public byte[] byteArr;
        // 音频文件
        public AudioClip audioClip;
        // 模块资源打包格式文件
        public UIAtlas uiAtlas;
        // fbx打包的文件对象
        public UnityEngine.Object mainAsset;
        // font文件
        public UIFont font;
       
    }
}

2. 此时我们需要一个函数。来解析下载完后的资源，并保存到 LoadParam 中。

/// <summary>
    ///  解析下载内容
    /// </summary>
    public LoadParam ParseLoadParamFromLoadRequest(LoadRequest request) {
        LoadParam param = new LoadParam();
        param.url = request.requestURL;
        param.priority = request.priotiry; // 为何param需要记录优先级？
        param.fileType = request.fileType;

        switch (request.fileType) {
            case LoadFileType.IMAGE:
                try {
                    param.texture2D = request.wwwObject.texture;
                    param.texture2D.Compress(false);    // compress 有何影响
                } catch (Exception exception) {
                    Debug.LogWarning("read texture2d error:" + request.requestURL +"\n" + exception.Message);
                }
                break;
            case LoadFileType.TXT:
                try {
                    param.text = request.wwwObject.text;
                } catch (Exception exception) {
                    Debug.LogWarning("read text error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.UNITY3D:
                try {
                    if (request.wwwObject.assetBundle != null) {
                        param.assetBundle = request.wwwObject.assetBundle;
                    }
                } catch (Exception exception) {
                    Debug.LogWarning("read assetBundle error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.MODULE_RESOURCE:
                try {
                    UnityEngine.Object[] data = request.wwwObject.assetBundle.LoadAll();
                    int length = data.Length;
                    for (int i = 0; i < length; i++) {
                        if (data[i] is GameObject) {
                            param.uiAtlas = (data[i] as GameObject).GetComponent<UIAtlas>();
                            break;
                        }
                    }
                    request.wwwObject.assetBundle.Unload(false);
                } catch (Exception exception) {
                    Debug.LogWarning("read uiatlas error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.JSON:
                try {
                    param.jsonData = request.wwwObject.text.Trim();
                } catch (Exception exception) {
                    Debug.LogWarning("read  json error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.FBX:
                try {
                    param.mainAsset = request.wwwObject.assetBundle.mainAsset;
                } catch (Exception exception) {
                    Debug.LogWarning("read  fbx error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.BINARY:
            case LoadFileType.BINARY_BG:
                try {
                    param.byteArr = request.wwwObject.bytes;
                } catch (Exception exception) {
                    Debug.LogWarning("read  binary error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.AUDIO:
                try {
                    UnityEngine.Object[] data = request.wwwObject.assetBundle.LoadAll();
                    int length = data.Length;
                    for (int i = 0; i < length; i++) {
                        if (data[i] is AudioClip) {
                            param.audioClip = data[i] as AudioClip;
                            break;
                        }
                    }
                    request.wwwObject.assetBundle.Unload(false);
                } catch (Exception exception) {
                    Debug.LogWarning("read audio error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
            case LoadFileType.FONT:
                try {
                    UnityEngine.Object[] data = request.wwwObject.assetBundle.LoadAll();
                    int length = data.Length;
                    for (int i = 0; i < length; i++) {
                        if (data[i] is UnityEngine.Transform) {
                            param.font = (data[i] as UnityEngine.Transform).GetComponent<UIFont>();
                            break;
                        }
                    }
                    request.wwwObject.assetBundle.Unload(false);
                } catch (Exception exception) {
                    Debug.LogWarning("read  font error:" + request.requestURL + "\n" + exception.Message);
                }
                break;
        }
        return param;
    }

3.我们发现，似乎还没有对下载队列进行检测，即检测WWW类下载的状态。是已经下载完成了呢，还是下载出错。

这个时候我们需要一个定时器。

每隔一定时间对下载队列进行检测，我们在构造函数那里添加一个定时器。

public LoadManager() {
        Application.backgroundLoadingPriority = ThreadPriority.Low;
        // add timer to check download queue
        FrameTimerManager.getInstance().add(1, 0, CheckQueue);
    }

其中的 CheckQueue() 函数是检测函数。

/// <summary>
    ///  定时器下，在每帧对下载队列进行检测
    ///  如果下载有问题，或者超时，则清除
    ///  如果下载完成，则解析下载结果，并进入completeDict中
    /// </summary>
    public void CheckQueue() {
        if (!isLoading) return;
        foreach (KeyValuePair<string, LoadRequest> pair in loadDict) {
            LoadRequest request = pair.Value;
            request.loadTotalFrames++;
            // deal error
            if ((request.wwwObject != null && request.wwwObject.error != null) || request.isTimeOut) {
                if (request.requestURL.Contains(".apk") || request.requestURL.Contains(".ipa")) {
                    return;
                }
                request.alreadyDeal = true;
                loadDict.Remove(request.requestURL);
                ErrorDelegateHandle(request);
                if (request.isTimeOut) {
                    Debug.LogWarning("Load time out:" + request.requestURL);
                } else {
                    Debug.LogWarning("Load error:" + request.requestURL);
                }
                MoveRequestFromWaitDictToLoadDict();
                break;
            }

            // 
            if (!request.alreadyDeal) {
                ProcessDelegateHandle(request);
                // if done
                if (request.wwwObject != null && request.wwwObject.isDone) {
                    LoadParam param = ParseLoadParamFromLoadRequest(request);
                    if (request.fileType != LoadFileType.BINARY) {
                        completeDict.Add(request.requestURL, param);
                    }
                    //
                    CompleteDelegateHandle(request, param);
                    //
                    request.alreadyDeal = true;
                    loadDict.Remove(request.requestURL);
                    MoveRequestFromWaitDictToLoadDict();
                    break;
                }
            }

        }
    }

至此，我们的LoadManager类即完成相应的功能。