iOS: UICollectionView Cell loading is very jerky

Question

Im using UICollectionView for showing listing of images using SDWebImage which is very jerky and the scroll is not smooth. Any suggestions as to how do I proceed with this?

below is code in

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{

    NSString * cellIdentifier = @"offersCell";

    HotDealsCollectionViewCell * cell = (HotDealsCollectionViewCell *)[self.productsCollectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

    cell.layer.shouldRasterize = YES;
    cell.layer.rasterizationScale = [UIScreen mainScreen].scale;

    cell.layer.shadowColor = [[UIColor colorWithRed:210.0/255.0 green:210.0/255.0 blue:210.0/255.0 alpha:1.0] CGColor];
    cell.layer.shadowOffset = CGSizeMake(2.0f, 2.0f);
    cell.layer.shadowRadius = 3.0f;
    cell.layer.shadowOpacity = 1.0f;
    cell.layer.masksToBounds = NO;
    CGRect shadowFrame = cell.layer.bounds;
    CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:shadowFrame].CGPath;
    cell.layer.shadowPath = shadowPath;

    cell.backgroundColor = [UIColor whiteColor];

    if ([self.productsArray count] > 0) {
        Product * product = [self.productsArray objectAtIndex:indexPath.item];
        cell.productName.text = product.productName;
        cell.productEndDate.hidden = NO;
        cell.productImageView.clipsToBounds = YES;
        cell.productEndDate.textAlignment = NSTextAlignmentCenter;

           [cell.productImageView sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"http://%@", product.productImage]] placeholderImage:[UIImage imageNamed:@"noProduct"]];


    }

return cell;
}

cell.layer.shouldRasterize = YES; cell.layer.rasterizationScale = [UIScreen mainScreen].scale; http://stackoverflow.com/questions/16454160/uicollectionview-has-slow-jerky-loading-of-images-and-scrolling — Muhammad Raheel Mateen, Feb 23 '16 at 07:13
@MuhammadRaheelMateen i have tried this.. but it doesnt work.. — user3355310, Feb 23 '16 at 07:14
[cell.productImageView sd_setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"http://%@", product.productImage]] placeholderImage:[UIImage imageNamed:@"noProduct"]]; — user3355310, Feb 23 '16 at 07:15
I have posted the code for cellForItemAtIndexPath.. Any help? @iPeter — user3355310, Feb 23 '16 at 07:52

score 1 · Answer 1 · answered Feb 23 '16 at 07:14

1

Thats due to Image allocation, try the following

-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
  cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void) {
  UIImage *image = [[UIImage imageWithCGImage:[list objectAtIndex:indexpath.row] thumbnailImage]];

    dispatch_sync(dispatch_get_main_queue(), ^(void) {
        cell.imageView.image = image;
    });
  });

  return cell;
}

answered Feb 23 '16 at 07:14

Murtaza Khursheed Hussain

15,176
7
58
83

Hi murtuza, what is the type of [list objectAtIndex:indexpath.row] – user3355310 Feb 23 '16 at 07:28
its a `UIImage` object in the list – Murtaza Khursheed Hussain Feb 23 '16 at 07:30
what is the actual problem you are facing with the above code ? – Murtaza Khursheed Hussain Feb 23 '16 at 08:20

score 0 · Answer 2 · answered Feb 23 '16 at 07:17

0

 if ([[SDWebImageManager sharedManager] diskImageExistsForURL:[NSURL URLWithString:url]]) {

        [self.imageView setImage:[[SDWebImageManager sharedManager].imageCache imageFromDiskCacheForKey:url]];

    } else {
        [self.imageViewsd_setImageWithPreviousCachedImageWithURL:[NSURL URLWithString:url]
                                                        placeholderImage:[UIImage imageNamed:@"placeholder.png"]
                                                                    options:SDWebImageRefreshCached progress:nil
                                                                  completed:nil];
    }

answered Feb 23 '16 at 07:17

Muhammad Raheel Mateen

610
3
10

please share your full code , and also the screen shot of your view – Muhammad Raheel Mateen Feb 23 '16 at 07:31
Edited.. please check above – user3355310 Feb 23 '16 at 07:36
Product * product = [self.productsArray objectAtIndex:indexPath.item]; Product * product = [self.productsArray objectAtIndex:indexPath.row]; – Muhammad Raheel Mateen Feb 23 '16 at 07:44
indexpath.row is the better option to use in array – Muhammad Raheel Mateen Feb 23 '16 at 07:52
it doesnt help anyway... any other approach ? – user3355310 Feb 23 '16 at 07:52
HotDealsCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:NSStringFromClass([HotDealsCollectionViewCell class]) forIndexPath:indexPath]; – Muhammad Raheel Mateen Feb 23 '16 at 07:54
and also remove your layer code first to test whether its working without your layer code or not – Muhammad Raheel Mateen Feb 23 '16 at 07:55
doesnt help.. i have tried that earlier.. the moment i load the images it becomes jerky – user3355310 Feb 23 '16 at 07:58
could you please share your sample json – Muhammad Raheel Mateen Feb 23 '16 at 08:18

score 0 · Answer 3 · answered Feb 23 '16 at 08:02

try this put below code in custom cell method

- (void)awakeFromNib
{

self.layer.shouldRasterize = YES;
self.layer.rasterizationScale = [UIScreen mainScreen].scale;

self.layer.shadowColor = [[UIColor colorWithRed:210.0/255.0 green:210.0/255.0 blue:210.0/255.0 alpha:1.0] CGColor];
self.layer.shadowOffset = CGSizeMake(2.0f, 2.0f);
self.layer.shadowRadius = 3.0f;
self.layer.shadowOpacity = 1.0f;
self.layer.masksToBounds = NO;
CGRect shadowFrame = cell.layer.bounds;
CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:shadowFrame].CGPath;
self.layer.shadowPath = shadowPath;

self.backgroundColor = [UIColor whiteColor];
}

and remove this from -cellForItemAtIndexPath

try this

commenting this also, i get the jerk.. so can you tel me something about the loading of images? — user3355310, Feb 23 '16 at 08:03

iOS: UICollectionView Cell loading is very jerky

3 Answers3