IOS开发网络篇之──ASIHTTPRequest示例（支持断点续传）

来源：互联网发布：java jdbc 批量insert 编辑：程序博客网时间：2024/06/03 18:59

一、创建网络请求队列

首先，创建网络请求队列，如下：

<span style="font-size:14px;">ASINetworkQueue *que = [[ASINetworkQueue alloc] init];self.netWorkQueue = que;[que release];[self.netWorkQueue reset];[self.netWorkQueue setShowAccurateProgress:YES];[self.netWorkQueue go];</span>

二、创建存放路径

<span style="font-size:14px;font-weight: normal;">//初始化Documents路径 NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]; //初始化临时文件路径 NSString *folderPath = [path stringByAppendingPathComponent:@"temp"]; //创建文件管理器 NSFileManager *fileManager = [NSFileManager defaultManager]; //判断temp文件夹是否存在 BOOL fileExists = [fileManager fileExistsAtPath:folderPath];  if (!fileExists) {//如果不存在说创建,因为下载时,不会自动创建文件夹  [fileManager createDirectoryAtPath:folderPath                withIntermediateDirectories:YES                                 attributes:nil                                     error:nil]; }</span>

三、发送下载请求

这里对下面几个对象说明一下：CustomCell是我自定义的cell，cell上面有下载和暂停两个按钮，其tag值为cell所在的行，因此这里的[sendertag]为下载按钮的tag值，self.downloadArray为array数组对象，存放要下载的资源字典信息，在该字典中有一键为URL，它对应的值就是我们下载链接。

这些东西，根据自己的实际需要改动一下即可使用

CustomCell *cell = (CustomCell *)[self.myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:[sender tag] inSection:0]]; NSString  *filePath = [[self.downloadArray objectAtIndex:[sender tag]] objectForKey:@"URL"]; NSLog(@"filePath=%@",filePath); //初始下载路径 NSURL *url = [NSURL URLWithString:filePath]; //设置下载路径 ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:url]; //设置ASIHTTPRequest代理 request.delegate = self; //初始化保存ZIP文件路径 NSString *savePath = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"book_%d.zip",[sender tag]]]; //初始化临时文件路径 NSString *tempPath = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"temp/book_%d.zip.temp",[sender tag]]]; //设置文件保存路径 [request setDownloadDestinationPath:savePath]; //设置临时文件路径 [request setTemporaryFileDownloadPath:tempPath];     //设置进度条的代理, [request setDownloadProgressDelegate:cell]; //设置是是否支持断点下载 [request setAllowResumeForFileDownloads:YES]; //设置基本信息 [request setUserInfo:[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:[sender tag]],@"bookID",nil]];     NSLog(@"UserInfo=%@",request.userInfo); //添加到ASINetworkQueue队列去下载 [self.netWorkQueue addOperation:request]; //收回request [request release];//暂停请求这里的cell下下载时的一样，CustomCell *cell = (CustomCell *)[self.myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:[sender tag] inSection:0]];        for (ASIHTTPRequest *request in [self.netWorkQueue operations]) {        NSInteger bookid = [[request.userInfo objectForKey:@"bookID"] intValue];//查看userinfo信息        if ([sender tag] == bookid) {//判断ID是否匹配            //暂停匹配对象            [request clearDelegatesAndCancel];        }    }

四、ASIHTTPRequestDelegate回调方法

上面已经把下载请求与暂停请求实现，点击下载时，开始下载资源；当点暂停时，下载中断；当我们再点击下载按钮时，继续下载，在第二步的

[request setAllowResumeForFileDownloads:YES]设置是是否支持断点下载。下面要实现ASIHTTPRequestDelegate代理方法如下：

#pragma mark -#pragma mark ASIHTTPRequestDelegate method//ASIHTTPRequestDelegate,下载之前获取信息的方法,主要获取下载内容的大小，可以显示下载进度多少字节- (void)request:(ASIHTTPRequest *)request didReceiveResponseHeaders:(NSDictionary *)responseHeaders { NSLog(@"didReceiveResponseHeaders-%@",[responseHeaders valueForKey:@"Content-Length"]);    NSLog(@"contentlength=%f",request.contentLength/1024.0/1024.0);    int bookid = [[request.userInfo objectForKey:@"bookID"] intValue];    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];    float tempConLen = [[userDefaults objectForKey:[NSString stringWithFormat:@"book_%d_contentLength",bookid]] floatValue];    NSLog(@"tempConLen=%f",tempConLen);    //如果没有保存,则持久化他的内容大小    if (tempConLen == 0 ) {//如果没有保存,则持久化他的内容大小        [userDefaults setObject:[NSNumber numberWithFloat:request.contentLength/1024.0/1024.0] forKey:[NSString stringWithFormat:@"book_%d_contentLength",bookid]];    }}//ASIHTTPRequestDelegate,下载完成时,执行的方法- (void)requestFinished:(ASIHTTPRequest *)request {        int bookid = [[request.userInfo objectForKey:@"bookID"] intValue];    CustomCell *cell = (CustomCell *)[self.myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:bookid inSection:0]];    cell.downloadCompleteStatus = YES;    cell.progressView.progress = 0.0; }

经过上述步骤，一个支持断点续传的功能程序实现了！

0 0