How to get download progress in AFNetworking 2.0?

You should observe the fractionCompleted property of your NSProgress object using KVO:

NSURL *url = [NSURL URLWithString:@"http://www.hfrmovies.com/TheHobbitDesolationOfSmaug48fps.mp4"];NSURLRequest *request = [NSURLRequest requestWithURL:url];AFHTTPSessionManager *session = [AFHTTPSessionManager manager];NSProgress *progress;NSURLSessionDownloadTask *downloadTask = [session downloadTaskWithRequest:request progress:&progress destination:^NSURL *(NSURL *targetPath, NSURLResponse *response) {    // …} completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error) {    [progress removeObserver:self forKeyPath:@"fractionCompleted" context:NULL];    // …}];[downloadTask resume];[progress addObserver:self            forKeyPath:@"fractionCompleted"               options:NSKeyValueObservingOptionNew               context:NULL];

Then add the observer method:

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{    if ([keyPath isEqualToString:@"fractionCompleted"]) {        NSProgress *progress = (NSProgress *)object;        NSLog(@"Progress… %f", progress.fractionCompleted);    } else {        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];    }}

Of course, you should check keyPath and/or object parameters to decide if that's the object/property you want to observe.

You can also use the setDownloadTaskDidWriteDataBlock: method from AFURLSessionManager (from which AFHTTPSessionManager inherits) to set a block for receiving download progress updates.

[session setDownloadTaskDidWriteDataBlock:^(NSURLSession *session, NSURLSessionDownloadTask *downloadTask, int64_t bytesWritten, int64_t totalBytesWritten, int64_t totalBytesExpectedToWrite) {    NSLog(@"Progress… %lld", totalBytesWritten);}];

This AFNetworking method maps the URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite: method from NSURLSessionDownloadDelegate protocol to a more convenient block mechanism.

BTW, Apple's KVO implementation is severely broken. I recommend using a better implementation like the one proposed by Mike Ash with MAKVONotificationCenter. If you are interested in reading why Apple's KVO is broken, read Key-Value Observing Done Right by Mike Ash.

I faced a similar problem, and found a solution.

Check the link below:http://cocoadocs.org/docsets/AFNetworking/2.0.1/Categories/UIProgressView+AFNetworking.html

#import <AFNetworking/UIKit+AFNetworking.h>

and use the additional method available to your UIProgressView

setProgressWithDownloadProgressOfTask:animated:

How I did it:

NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request  progress:nil destination:^NSURL *(NSURL *targetPath, NSURLResponse *response){    NSURL *documentsDirectoryPath = [NSURL fileURLWithPath:[NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) firstObject]];    return [documentsDirectoryPath URLByAppendingPathComponent:[targetPath lastPathComponent]];} completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error){    NSLog(@"File downloaded to: %@", filePath);}];[self.progressView setProgressWithDownloadProgressOfTask:downloadTask animated:YES];[downloadTask resume];

Simple solutions for Swift:

let sessionConfiguration = NSURLSessionConfiguration.defaultSessionConfiguration()let sessionManager = AFURLSessionManager(sessionConfiguration: sessionConfiguration)let request = NSURLRequest(URL: url)let sessionDownloadTask = sessionManager.downloadTaskWithRequest(request, progress: nil, destination: { (url, response) -> NSURL in            return destinationPath.URLByAppendingPathComponent(fileName) //this is destinationPath for downloaded file            }, completionHandler: { response, url, error in                //do sth when it finishes        })

Now you have 2 options:

1. Using UIProgressView and setProgressWithDownloadProgressOfTask:

   progressView.setProgressWithDownloadProgressOfTask(sessionDownloadTask, animated: true)

2. Using AFURLSessionManager and setDownloadTaskDidWriteDataBlock:

   sessionManager.setDownloadTaskDidWriteDataBlock { session, sessionDownloadTask, bytesWritten, totalBytesWritten, totalBytesExpectedToWrite in    let progress = Float(totalBytesWritten)/Float(totalBytesExpectedToWrite)        //do sth with current progress}

At the end do not forget about:

sessionDownloadTask.resume()