salmancs43 salmancs43 - 5 months ago 22
Objective-C Question

Download images from parse and show in UICollection View

I am downloading the images from parse and after that I am showing that images in uicollection view but when I scroll the collection view it hangs. Here is my code

-(void)viewWillAppear:(BOOL)animated
{
CGRect screen = [[UIScreen mainScreen] bounds];

CGFloat height = CGRectGetHeight(screen);

PFQuery * query = [PFQuery queryWithClassName:@"Static_Wallpaper"];
[query selectKeys:@[@"thumbnail"]];
if (height == 480) {
[query selectKeys:@[@"image4s"]];
}
else{
[query selectKeys:@[@"image6s"]];
}

[query findObjectsInBackgroundWithBlock:^(NSArray * objects, NSError * error){
if (!error) {
[imgArry arrayByAddingObjectsFromArray:objects];
imgArry = [[NSMutableArray alloc] initWithArray:objects];
NSLog(@"%lu",(unsigned long)imgArry.count);
[cllectionView reloadData];

}

}];

}


and Here is the code populating the images in collection view

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return imgArry.count;
}


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

CustomCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
PFObject *imageObject = [imgArry objectAtIndex:indexPath.row];
PFFile *imageFile = [imageObject objectForKey:@"image4s"];
[imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error){
NSLog(@"is there any data? %@", data);
cell.imgView.image = [UIImage imageWithData:data];
;

}
else {
NSLog(@"no data!");
}
}];



return cell;
}

Answer

By adding SDWebimage you need to do code like following:

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

    CustomCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
    PFObject *imageObject = [imgArry objectAtIndex:indexPath.row];
    PFFile *imageFile = [imageObject objectForKey:@"image4s"];
    NSString *UserProfile = [file url];

                    if([[SDWebImageManager sharedManager] diskImageExistsForURL:[NSURL URLWithString:UserProfile]])
                    {
                        NSString *key = [[SDWebImageManager sharedManager] cacheKeyForURL:[NSURL URLWithString:UserProfile]];
                        UIImage *image = [[SDImageCache sharedImageCache] imageFromDiskCacheForKey:key];
                        cell.imgView.image=image;
                    }
                    else
                    {
                        cell.imgView.image=[UIImage imageNamed:@"UserUpdationImageCell.png"];
                        [cell.imgView  sd_setImageWithURL:[NSURL URLWithString:UserProfile] placeholderImage:[UIImage imageNamed:@"UserUpdationImageCell.png"]];
                    }



    return cell;
}
Comments