AFNetworking 3.0 setImageWithURLRequest download p

Question

Does anyone have a nice working solution for getting the download progress when using the UIImageView+AFNetworking category and AFNetworking 3.0.

This category, which I did use for versions up till 3.0 has stopped working now.

Here is my own experimental version which sadly, for the moment, crashes randomly.

Answer 1

If you look at AFImageDownloader this, it is used by the UIImageView category to download images. In this class you

- (nullable AFImageDownloadReceipt *)downloadImageForURLRequest:  (NSURLRequest *)request
                                                    success:(nullable void (^)(NSURLRequest *request, NSHTTPURLResponse  * _Nullable response, UIImage *responseObject))success
                                                    failure:(nullable void (^)(NSURLRequest *request, NSHTTPURLResponse * _Nullable response, NSError *error))failure;

It returns a receipt which has a NSURLSessionDataTask *task property. NSURLSessionDataTask has different properties of how bytes download, expected bytes to receive etc. Perhaps you can use this and achieve your task.

Answer 2

You can achieve this by adding few lines in UIImageView+AFNetworking.h

1. Place this code at top of the file under the import statement

   static void * AFTaskCountOfBytesReceivedContext = &AFTaskCountOfBytesReceivedContext;
   

2. And you need to register the observer to track the bytes received by adding below line under the function setImageWithURLRequest at the position

   if (cachedImage) {
       // AFNetworking default code
   }
   else{
       // AFNetworking default code
       // Our new lines to track the download
       [self.af_activeImageDownloadReceipt.task addObserver:self forKeyPath:@"state" options:(NSKeyValueObservingOptions)0 context:AFTaskCountOfBytesReceivedContext];
       [self.af_activeImageDownloadReceipt.task addObserver:self forKeyPath:@"countOfBytesReceived" options:(NSKeyValueObservingOptions)0 context:AFTaskCountOfBytesReceivedContext];
   }
   

3. Add this new function at end.

   #pragma mark - NSKeyValueObserving
   
   - (void)observeValueForKeyPath:(NSString *)keyPath
                         ofObject:(id)object
                           change:(__unused NSDictionary *)change
                          context:(void *)context
   {
       if (context == AFTaskCountOfBytesReceivedContext) {
   
           if ([keyPath isEqualToString:NSStringFromSelector(@selector(countOfBytesReceived))]) {
               if ([object countOfBytesExpectedToReceive] > 0) {
                   dispatch_async(dispatch_get_main_queue(), ^{
                       //You can do your stuff at here like show progress
                       NSLog(@"Progress : %f",[object countOfBytesReceived] / ([object countOfBytesExpectedToReceive] * 1.0f));
   
                   });
               }
           }
   
           if ([keyPath isEqualToString:NSStringFromSelector(@selector(state))]) {
               if ([(NSURLSessionTask *)object state] == NSURLSessionTaskStateCompleted) {
                   @try {
                       [object removeObserver:self forKeyPath:NSStringFromSelector(@selector(state))];
                       NSLog(@"Image Download Complete");
                       if (context == AFTaskCountOfBytesReceivedContext) {
                           [object removeObserver:self forKeyPath:NSStringFromSelector(@selector(countOfBytesReceived))];
                       }
                   }
                   @catch (NSException * __unused exception) {}
               }
           }
       }
   }
   

Answer 3

Here is the modified version of AFNetworking 3.0 in which you can show a progress while loading image from server using UIImageView+AFNetworking category.

https://github.com/rushisangani/AFNetworking

Please replace following files with original AFNetworking files.

UIImageView+AFNetworking.h,
UIImageView+AFNetworking.m,

UIImage+ImageDownloader.h,
UIImage+ImageDownloader.m

NOTE: If you update your pod then this will be removed.