iOS: UICollectionView Cell loading is very jerky - ios

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;
}

Answer 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;
}

Answer 2

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];
}

Answer 3

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