Showing the file download progress with NSURLSessionDataTask

Question

I want to display file download progress (how many bytes are received) of particular file. It works fine with the NSURLSessionDownloadTask .My question is I want to achieve the same with the NSURLSessionDataTask.

Here is the code which receives file into NSData and writes to document folder:

NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];  NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]];  NSURLSessionDataTask * dataTask = [defaultSession dataTaskWithURL:theRessourcesURL     completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {         if(error == nil)        {              NSString *docsDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];                 NSString *pathToDownloadTo = [NSString stringWithFormat:@"%@/%@", docsDir, Name];                 NSLog(@"SIZE : %@",[NSByteCountFormatter stringFromByteCount:data.length countStyle:NSByteCountFormatterCountStyleFile]);                 [data writeToFile:pathToDownloadTo options:NSDataWritingAtomic error:&error];        } }];  [dataTask resume]; 

I am getting file size after write or complete datatask (after the file is received) :

NSLog(@"SIZE : %@",[NSByteCountFormatter stringFromByteCount:data.length countStyle:NSByteCountFormatterCountStyleFile]);

But i want to display it's current bytes received status, is this possible with NSURLSessionDataTask?

Answer 1

You need to implement following delegates:

<NSURLSessionDataDelegate, NSURLSessionDelegate, NSURLSessionTaskDelegate>

Also need to create two properties:

@property (nonatomic, retain) NSMutableData *dataToDownload; @property (nonatomic) float downloadSize;  - (void)viewDidLoad {     [super viewDidLoad];      NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];      NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]];      NSURL *url = [NSURL URLWithString: @"your url"];     NSURLSessionDataTask *dataTask = [defaultSession dataTaskWithURL: url];      [dataTask resume]; }  - (void)didReceiveMemoryWarning {     [super didReceiveMemoryWarning];     // Dispose of any resources that can be recreated. }  - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler {     completionHandler(NSURLSessionResponseAllow);      progressBar.progress=0.0f;     _downloadSize=[response expectedContentLength];     _dataToDownload=[[NSMutableData alloc]init]; }  - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {     [_dataToDownload appendData:data];     progressBar.progress=[ _dataToDownload length ]/_downloadSize; }