iOS網絡編程(六) NSURLSession詳解 · iOS 高級

昨夜瀏覽Demo的時候,看到別人請求網絡數據用的是NSURLSession,當時就在想這里什么,怎么沒有用過,引起了我的好奇心,遂去百度-谷歌-官方文檔一一查看,有了一定的了解,原來NSURLSession是iOS7中新的網絡接口，它與咱們熟悉的NSURLConnection是并列的。 ? ? ? 查找資料,寫了一個小Demo,大家可以看看,有什么不足的地方,可以留言幫我指出來. ~~~ // // HMTRootViewController.m // // // Created by HMT on 14-6-7. // Copyright (c) 2014年胡明濤. All rights reserved. // #import "HMTRootViewController.h" #import "HMTAppDelegate.h" @interface HMTRootViewController () @property (nonatomic,strong)UIImageView *imageView; @property (nonatomic,strong)UIProgressView *progressIndicator; @property (nonatomic,strong)NSURLSession *urlSession; // 普通會話 //@property (nonatomic,strong)NSURLSession *backgroundSession; // 后臺會話 @property (nonatomic,strong)NSURLSessionDownloadTask *sessionDownloadTask; // 下載Task @property (nonatomic,strong)NSURLSessionDownloadTask *resumableTask; // 恢復下載Task @property (nonatomic,strong)NSURLSessionDownloadTask *backgroundTask; // 后臺下載Task @property (nonatomic,strong)NSData *partialData; // 下載的局部數據 @end @implementation HMTRootViewController - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad{ [super viewDidLoad]; self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 64, 320, 300)]; [self.view addSubview:_imageView]; self.progressIndicator = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault]; _progressIndicator.frame = CGRectMake(50, 500, 220, 50); [self.view addSubview:_progressIndicator]; UIButton *cancleButton = [UIButton buttonWithType:UIButtonTypeSystem]; cancleButton.frame = CGRectMake(120, 400, 40, 40); [cancleButton setTitle:@"取消" forState:UIControlStateNormal]; [cancleButton addTarget:self action:@selector(didClickCancleButtonAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:cancleButton]; UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeSystem]; downloadButton.frame = CGRectMake(20, 400, 40, 40); [downloadButton setTitle:@"下載" forState:UIControlStateNormal]; [downloadButton addTarget:self action:@selector(didClickDownloadButtonAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:downloadButton]; UIButton *uploadButton = [UIButton buttonWithType:UIButtonTypeSystem]; uploadButton.frame = CGRectMake(70, 400, 40, 40); [uploadButton setTitle:@"上傳" forState:UIControlStateNormal]; [uploadButton addTarget:self action:@selector(didClickUploadButtonAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:uploadButton]; UIButton *resumableButton = [UIButton buttonWithType:UIButtonTypeSystem]; resumableButton.frame = CGRectMake(180, 400, 40, 40); [resumableButton setTitle:@"恢復" forState:UIControlStateNormal]; [resumableButton addTarget:self action:@selector(didClickResuableButtonAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:resumableButton]; UIButton *backgroundLoadButton = [UIButton buttonWithType:UIButtonTypeSystem]; backgroundLoadButton.frame = CGRectMake(220, 400, 80, 40); [backgroundLoadButton setTitle:@"后臺下載" forState:UIControlStateNormal]; [backgroundLoadButton addTarget:self action:@selector(didClickBackgroundButtonAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:backgroundLoadButton]; #pragma mark - 如果我們需要利用NSURLSession進行數據傳輸我們需要： /** * 創建一個NSURLSessionConfiguration，用于創建NSSession時設置工作模式(3種) * (1)一般模式（default）：工作模式類似于原來的NSURLConnection，可以使用緩存的Cache，Cookie，鑒權。 * (2)及時模式（ephemeral）：不使用緩存的Cache，Cookie，鑒權。 * (3)后臺模式（background）：在后臺完成上傳下載，創建Configuration對象的時候需要給一個NSString的ID用于追蹤完成工作的Session是哪一個 */ NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration]; /** * @網絡設置：參考NSURLConnection中的設置項 * 兩種創建方法(目前不太懂什么區別) * (1)就是根據剛才創建的Configuration創建一個Session，系統默認創建一個新的OperationQueue處理Session的消息 * (2)可以設定回調的delegate（注意這個回調delegate會被強引用），并且可以設定delegate在哪個OperationQueue回調，如果我們將其 * 設置為[NSOperationQueue mainQueue]就能在主線程進行回調非常的方便 */ //NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfig]; self.urlSession = [NSURLSession sessionWithConfiguration:sessionConfig delegate:self delegateQueue:[NSOperationQueue mainQueue]]; NSURL *url = [NSURL URLWithString:@"http://www.bizhiwa.com/uploads/allimg/2012-01/22021207-1-311536.jpg"]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; /** * NSURLSessionUploadTask：上傳用的Task，傳完以后不會再下載返回結果； * NSURLSessionDownloadTask：下載用的Task； * NSURLSessionDataTask：可以上傳內容，上傳完成后再進行下載。 */ self.sessionDownloadTask = [self.urlSession downloadTaskWithRequest:request]; // 同NSURLConnection一樣,有代理方法也就有block方法 // [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { // }]; } #pragma mark 點擊下載 - (void)didClickDownloadButtonAction:(UIButton *)button{ // 因為任務默認是掛起狀態，需要恢復任務（執行任務） [_sessionDownloadTask resume]; } #pragma mark 點擊上傳 - (void)didClickUploadButtonAction:(UIButton *)button{ //判斷imageView是否有內容 if (_imageView.image == nil) { NSLog(@"image view is empty"); return; } // 0. 上傳之前在界面上添加指示符 UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray]; // 設置位置??? CGSize size = _imageView.bounds.size; indicator.center = CGPointMake(size.width / 2.0, size.height / 2.0); [self.imageView addSubview:indicator]; [indicator startAnimating]; // 1. URL NSURL *url = [NSURL URLWithString:@"http://www.bizhiwa.com/uploads/allimg/2012-01/22021207-1-311536.jpg"]; // 2. Request -> PUT,request的默認操作是GET NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:5.0f]; request.HTTPMethod = @"PUT"; // *** 設置網絡請求的身份驗證! *** // 1> 授權字符串 NSString *authStr = @"admin:123456"; // 2> BASE64的編碼,避免數據在網絡上以明文傳輸 // iOS中,僅對NSData類型的數據提供了BASE64的編碼支持 NSData *authData = [authStr dataUsingEncoding:NSUTF8StringEncoding]; NSString *encodeStr = [authData base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithCarriageReturn]; NSString *authValue = [NSString stringWithFormat:@"Basic %@", encodeStr]; [request setValue:authValue forHTTPHeaderField:@"Authorization"]; // 3. Session NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration]; NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfig delegate:self delegateQueue:[NSOperationQueue mainQueue]]; // 4. UploadTask NSData *imageData = UIImageJPEGRepresentation(_imageView.image, 0.75); // 應用block的請求方式 NSURLSessionUploadTask *uploadTask = [session uploadTaskWithRequest:request fromData:imageData completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { // 上傳完成后,data參數轉換成string就是服務器返回的內容 NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; NSLog(@"OK -> %@", str); [NSThread sleepForTimeInterval:5.0f]; dispatch_async(dispatch_get_main_queue(), ^{ [indicator stopAnimating]; [indicator removeFromSuperview]; }); }]; // 因為任務默認是掛起狀態，需要恢復任務（執行任務） [uploadTask resume]; } #pragma mark 點擊取消 // NSURLConnection一旦發送是沒法取消的。但是，我們可以很容易的取消掉一個NSURLSessionTask任務 - (void)didClickCancleButtonAction:(UIButton *)button{ /** * 當取消后，會回調這個URLSession:task:didCompleteWithError:代理方法，通知你去及時更新UI。當取消一個任務后，也 * 十分可能會再一次回調這個代理方法URLSession:downloadTask:didWriteData:BytesWritten:totalBytesExpectedToWrite: * 當然，didComplete 方法肯定是最后一個回調的。 */ // if (_sessionDownloadTask) { // // // 取消下載請求 // [_sessionDownloadTask cancel]; // _sessionDownloadTask = nil; // } if (!self.sessionDownloadTask) { // 停止下載任務,把待恢復的數據保存到一個變量中，方便后面恢復下載使用 [self.sessionDownloadTask cancelByProducingResumeData:^(NSData *resumeData) { self.partialData = resumeData; self.sessionDownloadTask = nil; }]; } } #pragma mark 恢復下載(斷點續傳) - (void)didClickResuableButtonAction:(UIButton *)button{ if (self.partialData) { self.sessionDownloadTask = [self.urlSession downloadTaskWithResumeData:self.partialData]; self.partialData = nil; }else{ NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://pic4.duowan.com/wow/1002/130782267821/130782458426.jpg"]]; self.resumableTask = [self.urlSession downloadTaskWithRequest:request]; } [self.sessionDownloadTask resume]; } #pragma mark 后臺下載模式 - (void)didClickBackgroundButtonAction:(UIButton *)button{ NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://dldir1.qq.com/qqfile/QQforMac/QQ_V3.1.2.dmg"]]; self.backgroundTask = [[self backgroundSession] downloadTaskWithRequest:request]; [self.backgroundTask resume]; } #pragma mark - NSURLSessionDownloadTaskDelegate // 下載完成 - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location{ /** *******->appDelegete里面的方法 typedef void(^MyBlock)(); @property (copy, nonatomic) MyBlock backgroundURLSessionCompletionHandler; // 后臺請求結束時調用的方法 - (void)application:(UIApplication *)application handleEventsForBackgroundURLSession:(NSString *)identifier completionHandler:(void (^)())completionHandler{ self.backgroundURLSessionCompletionHandler = completionHandler; } */ // 如果是后臺NSURLSession,后臺請求結束后會調用這個方法,通知你應該更新UI了 if (session == [self backgroundSession]) { self.backgroundTask = nil; HMTAppDelegate *appDelegate = (HMTAppDelegate *)[UIApplication sharedApplication].delegate; if (appDelegate.backgroundURLSessionCompletionHandler) { void(^handler)() = appDelegate.backgroundURLSessionCompletionHandler; appDelegate.backgroundURLSessionCompletionHandler = nil; handler(); } } // 這里的緩存處理做的不好,大家按自己的方法處理就行,還有圖片的存儲以它本身的URL路徑為準,這樣是不會有重復的 NSFileManager *fileManager = [NSFileManager defaultManager]; NSURL *cachesURLPath = [[fileManager URLsForDirectory:NSCachesDirectory inDomains:NSUserDomainMask] lastObject]; // 根據URL獲取到下載的文件名,拼接成沙盒的存儲路徑(location是下載的臨時文件目錄,在tmp文件夾里面) NSURL *destinationPath = [cachesURLPath URLByAppendingPathComponent:[location lastPathComponent]]; NSError *error = nil; BOOL success = [fileManager moveItemAtURL:location toURL:destinationPath error:&error]; [fileManager removeItemAtURL:location error:NULL]; // location是下載的臨時文件目錄,將文件從臨時文件夾復制到沙盒 // BOOL success = [fileManager copyItemAtURL:location toURL:destinationPath error:&error]; if (success) { dispatch_async(dispatch_get_main_queue(), ^{ UIImage *image = [UIImage imageWithContentsOfFile:[destinationPath path]]; self.imageView.image = image; // UIImageView會自動裁剪圖片適應它的frame,下面這個屬性就是展示原圖 self.imageView.contentMode = UIViewContentModeScaleAspectFill; }); } } // 不管任務是否成功，在完成后都會回調這個代理方法 - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error{ // 如果error是nil，則證明下載是成功的，否則就要通過它來查詢失敗的原因。如果下載了一部分，這個error會包含一個NSData對象，如果后面要恢復任務可以用到 if (error == nil) { dispatch_async(dispatch_get_main_queue(), ^{ self.progressIndicator.hidden = YES; }); } } // 傳輸進度 - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{ double currentValue = totalBytesWritten / (double)totalBytesExpectedToWrite; dispatch_async(dispatch_get_main_queue(), ^{ NSLog(@"%f",currentValue); self.progressIndicator.hidden = NO; self.progressIndicator.progress = currentValue; }); } // 未知 - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes{ } #pragma mark - NSURLSession另一個重要的特性：即使當應用不在前臺時，你也可以繼續傳輸任務。當然，我們的會話模式也要為后臺模式 - (NSURLSession *)backgroundSession{ // 通過給的后臺token，我們只能創建一個后臺會話，所以這里使用dispatch once block static NSURLSession *backgroundSession = nil; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ NSURLSessionConfiguration *config = [NSURLSessionConfiguration backgroundSessionConfiguration:@"com.shinobicontrols.BackgroundDownload.BackgroundSession"]; backgroundSession = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil]; }); return backgroundSession; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } /* #pragma mark - Navigation // In a storyboard-based application, you will often want to do a little preparation before navigation - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { // Get the new view controller using [segue destinationViewController]. // Pass the selected object to the new view controller. } */ @end ~~~ @不錯的NSURLSession文章 [iOS 7系列譯文：忘記NSURLConnection，擁抱NSURLSession吧！](http://jishu.zol.com.cn/201091.html)