我正在尝试构建一个应用程序，该应用程序将显示一系列可以下载然后阅读的杂志。我想要发生的是，如果没有下载杂志，当点击一个单元格时将开始下载，并且相应的单元格中将出现一个进度视图，显示下载进度。我已经子类化UICollectionViewCell并添加了一个UIProgressView属性。到目前为止，我已经能够检查文件是否已下载，如果没有，请下载它，如果是，只需使用PDF library called VFR Library. 我还可以更新放置在 之外的进度视图，UICollectionViewCell但无法更新放置在UICollectionViewCell. 不幸的是，我下载和更新进度视图的大部分逻辑都在didSelectItemAtIndexPath:. 我知道这并不优雅，但我的经验水平还不够高，无法有效地开发自己的课程以无缝协作。但是一旦我弄清楚了这一点，我将致力于改进代码并抽象一些东西。无论如何，这就是我正在做的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];
}
}
那么有什么方法可以更新此方法中相应单元格内的进度视图，还是我需要做其他事情才能使其正常工作？谢谢你提供的所有帮助。