Question

I am trying to implement UICollectionView and show images. I am using SDWebimage which works perfectly in tableviewcells but when i tried to use it in UICollectionviewCell it doesn’t stop and remove activityindicator. It does place the placeholder image if there is no downloaded image. I am not sure what is the difference between tableviewcell and collectionviewcell that might cause this problem.

Here is the code:

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"personImageCell";

    PersonCollectionViewCell *cell = (PersonCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
    Person *person = [self.fetchedResultsController objectAtIndexPath:indexPath];
    NSString *imgURL=[person.imageurl stringByAppendingString:@"?maxheight=300&maxwidth=400"];

    UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    activityIndicator.hidesWhenStopped = YES;
    activityIndicator.hidden = NO;
    [activityIndicator startAnimating];
    activityIndicator.center = CGPointMake(cell.ivPersonImage.frame.size.width /2, cell.ivPersonImage.frame.size.height/2);
    [cell.ivPersonImage setImageWithURL:[NSURL URLWithString:imgURL] placeholderImage:nil options:SDWebImageProgressiveDownload success:^(UIImage *image, BOOL cached){
        [activityIndicator stopAnimating];[activityIndicator removeFromSuperview];
        NSLog(@"activity indicator should be removed");
    }failure:^(NSError *error){
        [activityIndicator stopAnimating];[activityIndicator removeFromSuperview];
        cell.ivPersonImage.image = [UIImage imageNamed:@"placeholder.png"];
    }];


    [cell.ivPersonImage addSubview:activityIndicator];
    return cell;
}

UPDATE:

When i do NSLog(@"activity indicator should be removed %@,activityIndicator);

I get this output:

 activity indicator should be removed <UIActivityIndicatorView: 0xa520ab0; frame = (65 90; 20 20); hidden = YES; layer = <CALayer: 0xa520b60>> 

It shows that UIActivityindicator is hidden but it is still showing on top of the image

Answer 1

It seems that you are reusing cell so there are more then one UIActivityIndicatorViews.

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"personImageCell";

    PersonCollectionViewCell *cell = (PersonCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
    Person *person = [self.fetchedResultsController objectAtIndexPath:indexPath];
    NSString *imgURL=[person.imageurl stringByAppendingString:@"?maxheight=300&maxwidth=400"];

    UIActivityIndicatorView *activityIndicator = [cell.ivPersonImage viewWithTag:10];
    if (activityIndicator) [activityIndicator removeFromSuperview];
    activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    activityIndicator.hidesWhenStopped = YES;
    activityIndicator.hidden = NO;
    [activityIndicator startAnimating];
    activityIndicator.center = cell.ivPersonImage.center;
    activityIndicator.tag = 10;

    [cell.ivPersonImage addSubview:activityIndicator];
    [cell.ivPersonImage setImageWithURL:[NSURL URLWithString:imgURL] placeholderImage:nil options:SDWebImageProgressiveDownload success:^(UIImage *image, BOOL cached){
        [activityIndicator stopAnimating];[activityIndicator removeFromSuperview];
        NSLog(@"activity indicator should be removed");
    }failure:^(NSError *error){
        [activityIndicator stopAnimating];[activityIndicator removeFromSuperview];
        cell.ivPersonImage.image = [UIImage imageNamed:@"placeholder.png"];
    }];

    return cell;
}