AFNetworking断点续传、下载图片

下载图片：下载图片后保存在本地文件中

//在lock和挂起状态都会下载
NSURLRequest *request=[[NSURLRequest alloc]initWithURL:[NSURL URLWithString:@"http://attach.bbs.miui.com/forum/201110/05/082552rm0v11zlv1axd13l.png"]];
//操作配置
AFHTTPRequestOperation *requestOperator=[[AFHTTPRequestOperation alloc]initWithRequest:request];
requestOperator.responseSerializer=[AFImageResponseSerializer serializer];
[requestOperator setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject){
    //主线程中执行
    self.pictureView.image=responseObject;
    NSString *fileDestination=[NSHomeDirectory() stringByAppendingString:@"/Documents/1.png"];
    <span style="color:#ff6666;">//若respondObject为NSData，则用下面的方法</span>
    /*NSFileManager *fileManage=[NSFileManager defaultManager];
    if([fileManage createFileAtPath:fileDestination contents:imgData attributes:nil]){
        NSLog(@"%@",fileDestination);
    }*/
    if([UIImageJPEGRepresentation(responseObject, 1.0) writeToFile:fileDestination atomically:YES]){
        //成功后运行
        NSLog(@"%@",fileDestination);
    }  

} failure:^(AFHTTPRequestOperation *operation, NSError *error){
    NSLog(@"error:%@",error);
}];
//监听下载进度
[requestOperator setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead){
    self.progressView.progress=totalBytesRead*1.0/totalBytesExpectedToRead;
    //NSLog(@"%.3f",totalBytesRead*1.0/totalBytesExpectedToRead);
}];
//开始执行
[requestOperator start];  

断点续传：暂停和开始下载的按钮我都是一个按钮，所以定义了AFHTTPRequestOperation *resumeOperation和一个BOOL类型的resume判断是否续传。

因为在block中又调用了self，会造成内存泄露，所以定义了__weak的weakSelf解决内存泄露的问题

<span style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; background-color: inherit;"><span style=</span><span class="string" style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; color: blue; background-color: inherit;">"color:#ff0000;"</span><span style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; background-color: inherit;">>__weak </span><span class="keyword" style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); background-color: inherit; font-weight: bold;">ViewController</span><span style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; background-color: inherit;"> *weakSelf=</span><span class="keyword" style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); background-color: inherit; font-weight: bold;">self</span><span style="line-height: 18px; font-family: Consolas, 'Courier New', Courier, mono, serif; margin: 0px; padding: 0px; border: none; background-color: inherit;">;</span>  </span>

if(!self.resumeOperation){
        NSURLRequest *request=[[NSURLRequest alloc]initWithURL:[NSURL URLWithString:@"http://attach.bbs.miui.com/forum/201110/05/082552rm0v11zlv1axd13l.png"]];
        self.resumeOperation=[[AFHTTPRequestOperation alloc]initWithRequest:request];
        self.resumeOperation.responseSerializer=[AFImageResponseSerializer serializer];
        [weakSelf.resumeOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject){
            //主线程中执行
            self.pictureView.image=responseObject;
            //保存文件
            NSString *fileDestination=[NSHomeDirectory() stringByAppendingString:@"/Documents/1.png"];
            if([UIImageJPEGRepresentation(responseObject, 1.0) writeToFile:fileDestination atomically:YES]){
                NSLog(@"%@",fileDestination);
            }
            self.resumeOperation=nil;  

        } failure:^(AFHTTPRequestOperation *operation, NSError *error){
            self.resumeOperation=nil;
            NSLog(@"error:%@",error);
        }];
        //监听下载进度
        [weakSelf.resumeOperation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead){
            self.progressView.progress=totalBytesRead*1.0/totalBytesExpectedToRead;
            //NSLog(@"%.3f",totalBytesRead*1.0/totalBytesExpectedToRead);
        }];
        //开始执行
        [self.resumeOperation start];
    }else if(!self.resume){
        [self.resumeOperation pause];
        self.resume=YES;
    }else{
        //继续
        [self.resumeOperation resume];
        self.resume=NO;
    }