UICollectionView with custom UICollectionViewCell?

Question

iOS

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
AnnouncementCollectionViewCell *cell = (AnnouncementCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:kCollectionViewCellIdentifier forIndexPath:indexPath];
NSURL *url = [NSURL fileURLWithPath: fileName isDirectory: NO];
[cell.announcement setDelegate:self];
[cell.announcement loadRequest:[NSURLRequest requestWithURL:url]];
int contentHeight = [[cell.announcement stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] integerValue];
NSLog(@"Content Height %d", contentHeight);
CGRect rect = cell.announcement.frame;
rect.size.height = contentHeight;
cell.announcement.frame = rect;
cell.autoresizesSubviews = YES;
cell.frame = rect;
return cell;
}
When filling the collection with data, the
webView does not have time to load the content yet, when the height of the element begins to be calculated
How to make the content load first and then the height of the element is calculated.
If using dispatch_sync the application crashes when loading the collection

Answer 1

Don't touch the height in cellForItemAtIndexPath at all. Only after loading data in UIWebView change the height of this webView. When it does, just call - (void)reloadItemsAtIndexPaths:(NSArray *)indexPaths on the indexPath that this webView matches. This will update the content of the desired cell and ask the delegate for its size.
If you are using UICollectionViewDelegateFlowLayout pass the required dimensions to - (CGSize)collectionView:(UICollectionView *)aCollectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath . This method will be called by itself after calling reloadItemsAtIndexPaths