ios - AFNetworking download with progressive UIAlertView

I want to implement a UIAlertView which will show when [[AFHTTPRequestOperationManager manager] GET:] will start doing its job and will disappear automatically when the job is done. One cool extra feature would be if I could display UIProgressView with progress of AFHTTPRequestOperation.

For now I'm checking if a have anything in Core Data and based on that I initialize UIAlertView:

if (![self coreDataHasEntriesForEntityName:@"Group"]) {          downloadingAlert = [[UIAlertView alloc] initWithTitle:@"Pobieranie" message:@"Trwa pobieranie grup" delegate:nil cancelButtonTitle:@"Anuluj" otherButtonTitles:nil, nil];          [self collectData];      } else {          NSError *error;          [[self fetchedResultsController] performFetch:&error];      }  

So to prevent from showing this alert when UITableView is already filled with data. As you can see I'm calling this [self collectData] method which looks like:

-(void)collectData  {      [downloadingAlert show];        [[AFHTTPRequestOperationManager manager] GET:ALL_GROUPS parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {          NSManagedObjectContext *tempContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];          tempContext.parentContext = self.moc;            [tempContext performBlock:^{                // Doing something with responseObject                if (![tempContext save:&error]) {                  NSLog(@"Couldn't save: %@", [error localizedDescription]);              }                [self.moc performBlock:^{                  NSError *error;                  if (![self.moc save:&error]) {                      NSLog(@"Couldn't save: %@", [error localizedDescription]);                  }                    [downloadingAlert dismissWithClickedButtonIndex:0 animated:YES];                    [self.writer performBlockAndWait:^{                      NSError *error;                      if (![self.writer save:&error]) {                          NSLog(@"Couldn't save: %@", [error localizedDescription]);                      }                  }];                }];          }];      } failure:^(AFHTTPRequestOperation *operation, NSError *error) {          // Show alert with info about failure      }];  }  

As you can see I'm programatically showing this UIAlertView and dismissing it when downloading is completed and UITableView is reloaded. But I have no clue how to add UIProgressView or how to dismiss this UIAlertView without using dismissWithClickedButtonIndex:. Any ideas?

source: stackoverflow.com