Update UIProgressView in UICollectionViewCell - ios

Question

I'm trying to build an app that will display a collection of magazines that can be downloaded and then read. What I want to happen is if the magazine isn't downloaded, a download will commence when a cell is tapped and a progressview will appear in the corresponding cell showing the download progress. I have subclassed UICollectionViewCelland added a UIProgressView property. So far, I've been able to check whether the file is downloaded and if it isn't, download it, and if it is, just open it using a PDF library called VFR Library. I can also update a progress view placed outside of the UICollectionViewCell but I can't update one placed within the UICollectionViewCell. Unfortunately, most of my logic for downloading and updating the progressview is within didSelectItemAtIndexPath:. I know this isn't elegant but my experience level isn't high enough that I can effectively develop my own classes to work together seamlessly. But once I figure this out I'll work on refining the code and abstracting things away a bit. Anyway, here's what I'm doing in didSelectItemAtIndexPath:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
IssueCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
self.navBarLabel.hidden = YES;
self.mainProgressView.hidden = NO;
self.view.userInteractionEnabled = NO;
//self.activityIndicator.hidden = NO;
[self.activityIndicator startAnimating];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [[[paths objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:#"issue%ld", (long)indexPath.row]]stringByAppendingPathExtension:#"pdf"];
if ([[NSFileManager defaultManager]fileExistsAtPath:path])
{
ReaderDocument *document = [ReaderDocument withDocumentFilePath:path password:nil];
if (document != nil)
{
//opens PDF for viewing
ReaderViewController *readerViewController = [[ReaderViewController alloc] initWithReaderDocument:document];
readerViewController.delegate = self;
readerViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
readerViewController.modalPresentationStyle = UIModalPresentationFullScreen;
[self presentViewController:readerViewController animated:YES completion:nil];
self.mainProgressView.hidden = YES;
self.navBarLabel.hidden = NO;
self.view.userInteractionEnabled = YES;
//self.activityIndicator.hidden = YES;
[self.activityIndicator stopAnimating];
}
}
else
{
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlArray[indexPath.row]]];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
operation.outputStream = [NSOutputStream outputStreamToFileAtPath:path append:NO];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"Successfully downloaded file to %#", path);
ReaderDocument *document = [ReaderDocument withDocumentFilePath:path password:nil];
if (document != nil)
{
//opens PDF for viewing
ReaderViewController *readerViewController = [[ReaderViewController alloc] initWithReaderDocument:document];
readerViewController.delegate = self;
readerViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
readerViewController.modalPresentationStyle = UIModalPresentationFullScreen;
[self presentViewController:readerViewController animated:YES completion:nil];
self.mainProgressView.hidden = YES;
self.navBarLabel.hidden = NO;
//self.activityIndicator.hidden = YES;
self.view.userInteractionEnabled = YES;
[self.activityIndicator stopAnimating];
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#"Download Failed" message:#"There was a problem downloading this issue" delegate:self cancelButtonTitle:#"OK" otherButtonTitles: nil];
[alertView show];
self.mainProgressView.hidden = YES;
self.navBarLabel.hidden = NO;
[self.activityIndicator stopAnimating];
//self.activityIndicator.hidden = YES;
self.view.userInteractionEnabled = YES;
NSLog(#"Error: %#", error);
}];
[operation setDownloadProgressBlock:^(NSUInteger bytesWritten, long long totalBytesWritten, long long totalBytesExpectedToWrite) {
float percentDone =((float)((int)totalBytesWritten) / (float)((int)totalBytesExpectedToWrite));
self.mainProgressView.progress = percentDone;
[cell.progressView setProgress:percentDone];
[self.collectionView reloadData];
// [cell.progressView performSelectorOnMainThread:#selector(loadingProgress:) withObject:[NSNumber numberWithFloat:percentDone] waitUntilDone:NO];
NSLog(#"Sent %lld of %lld bytes, %#", totalBytesWritten, totalBytesExpectedToWrite, path);
}];
[operation start];
}
}
So is there any way that I can update the progress view within a corresponding cell within this method or is there something else I need to do to get it to work? Thanks for any help you can give.

Answer 1

Well, I've finally solved my own problem. Apparently the problem was due to not fully understanding how to reference a particular item in a UICollectionView. All I had to do was create a method that actually did this and then call it in the "setDownloadProgressBlock:" method above. The method I wrote for this is:
- (void)setProgressAtIndex:(NSInteger)index withProgress:(float)progress
{
IssueCell *cell = (IssueCell *)[self.collectionView cellForItemAtIndexPath:[NSIndexPath indexPathForRow:index inSection:0]];
[cell.progressView setProgress:0.0];
[cell.progressView setProgress:progress];
}
The important line in this method is the first one where I grab a reference to the desired cell. This one actually grabs the cell that was tapped, whereas before I guess I was just referring to all the cells in general? I'm not too sure, but I would definitely appreciate it if someone had a better explanation.
This method was then called like so:
[self setProgressAtIndex:indexPath.row withProgress:percentDone];
Again, I did this inside the block in "setDownloadProgressBlock:".
Hopefully this helps someone else in the future!

Answer 2

Update your progress view on your main thread. Try using dispatch_sync(dispatch_get_main_queue()).