NSURLSession下载和断点续传(烟台杰瑞教育IOS培训部原创)

1、NSURLSession下载和断点续传NSURLSession是iOS7以后新的网络接口，和常经常使用到NSURLConnection是类似的。在程序在前台时，NSURLSession与NSURLConnection能够彼此的替代。可是当用户在对程序进行强制关闭的时候现在NSURLSession会默许的自动断开。相较而言NSURLSession的优势要紧体此刻后台操作时候，而且在最流行的框架AFNetworking中也对NSURLSession提供了更好的支持。要紧提供的功能如下：1下载文件到内存中2下载文件到途径3上传制定的文件等案例演示：图片下载断点续传豆Ieu底皿.PhMQi屯.Iphx

2、口片/©91，5W号卜要紧代码：一、概念几个全局变量©interfaceViewController()NSURLSessionDownloadTask*_task;NSData*_data;NSURLSession*_session;NSURLRequest*_request;UlProgressView*_pro;UllmageView*_imageView;二、向视图中添加图片进度条_imageView=UIImageViewallocinitWithFrame:CGRectMake(0,0,300,300);_imageView.center=self.view.c

3、enter;self.viewaddSubview:_imageView;_pro=UIProgressViewallocinitWithFrame:CGRectMake(_imageView.frame.origin.x,_imageView.frame.origin.y+400,300,40);3、向视图中添加按钮(一样的方式添加三个)UIButton*button=UIButtonallocinitWithFrame:CGRectMake(50,_imageView.frame.origin.y+400+20,50,40);button.backgroundColor=UIColorbl

4、ueColor;buttonsetTitle:听始"forState:UIControlStateNormal;buttonaddTarget:selfaction:selector(ddLoad)forControlEvents:UIControlEventTouchUpInside;button.layer.borderWidth=1;button.layer.borderColor=UIColorblueColor.CGColor;button.layer.cornerRadius=5;self.viewaddSubview:button;4、通过AFNetworkReacha

5、bilityManager网络状态监测- (void)_checkNet/开启网络状态监控AFNetworkReachabilityManagersharedManagerstartMonitoring;AFNetworkReachabilityManagersharedManagersetReachabilityStatusChangeBlockd(AFNetworkReachabilityStatusstatus)if(status=AFNetworkReachabilityStatusReachableViaWiFi)NSLog(当前是wifi");if(status=AFNe

6、tworkReachabilityStatusReachableViaWWAN)NSLog('当前是3G");if(status=AFNetworkReachabilityStatusNotReachable)NSLog('当前是没有网络”)；if(status=AFNetworkReachabilityStatusUnknown)NSLog('当前是未知网络")；五、开始下载- (void)ddLoadNSURLSessionConfiguration*config=NSURLSessionConfigurationdefaultSessionCo

7、nfiguration;_session=NSURLSessionsessionWithConfiguration:configdelegate:selfdelegateQueue:nil;/NSURL*url=NSURLURLWithString:src;_request=NSURLRequestrequestWithURL:url;NSLog(开始加载”)；_taskresume;六、设置暂停和答复- (void)pause/暂停NSLog(暂停下载")；_taskcancelByProducingResumeDatai(NSData*resumeData)_data=resum

8、eData;；_task=nil;- (void)resume/恢复NSLog(恢复下载”)；if(!_data)NSURL*url=NSURLURLWithString:src;_request=NSURLRequestrequestWithURL:url；_task=_sessiondownloadTaskWithRequest:_request;else_task=_sessiondownloadTaskWithResumeData:_data;_taskresume;7、代理方式保留下载文件监控下载进度#pragmamark-delegate-(void)URLSession:(NSU

9、RLSession*)sessiondownloadTask:(NSURLSessionDownloadTask*)downloadTaskdidFinishDownloadingToURL:(NSURL*)locationNSURL*url=NSURLfileURLWithPath:"/Users/jredu/Desktop/tt.png"NSFileManager*manager=NSFileManagerdefaultManager;managermoveItemAtURL:locationtoURL:urlerronnil;dispatch_async(dispat

10、ch_get_main_queue(),ANSData*data=managercontentsAtPath:"/Users/jredu/Desktop/tt.png"Ullmage*image=UIImageallocinitWithData:data;_imageView.image=image;UIAlertView*alert=UIAlertViewallocinitWithTitle:nilmessage:'下载完成"delegate:selfcancelButtonTitle:"OK"otherButtonTitles:nil;alertshow;);-(void)URLSession:(NSURLSession*)sessiondownloadTask:(NSURLSessionDownloadTask*)downloadTaskdidWriteData:(int64_t)bytesWrittentotalBytesWritten:(int64_t)totalBytesWrittentotalBytesExpectedToWr