CODEWITHSUNDEEP
iosobjective-cparse-platformuicollectionview
farhan
farhan

Reputation: 233

Sometimes when i go to my collectionView, its blank

i have everything working it seems, but i noticed sometimes when i go to the collection view, its blank, but when i refresh it, everything is loaded and shown.

here is my cellForItemAtIndexPath

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    static NSString * const reuseIdentifier = @"imageCell";
    imageCollectionCell *cell = [self.myCollectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];
    // Configure the cell

    PFFile *imageFile = [imageObject objectForKey:@"image"];
    [imageFile getDataInBackgroundWithBlock:^(NSData * _Nullable data, NSError * _Nullable error) {
        if (!error) {

            cell.imageViewCell.image = [UIImage imageWithData:data];
            cell.imageViewCell.contentMode UIViewContentModeScaleAspectFill;

        }
        else{
            NSLog(@"Fail");
        }
    } progressBlock:^(int percentDone) {

    }];
    return cell;
}

here is my query for the collectionview

- (void) queryData {
    imageCollectionCell *cell = (imageCollectionCell *)[self.myCollectionView cellForItemAtIndexPath:[[self.myCollectionView indexPathsForSelectedItems] firstObject]];
    cell.imageViewCell.image = nil;

    NSLog(@"initiated");
    [self.refreshControl endRefreshing];

    PFObject *queryPhotos = self.userInformationObject;
    PFQuery *query = [PFQuery queryWithClassName:@"Photo"];
    [query whereKey:@"userTookPhoto" equalTo:queryPhotos];
    [query orderByAscending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray * _Nullable objects, NSError * _Nullable error)
    {
    if (!error) {
        NSLog(@"Query no error");
        imageFilesArray = [[NSArray alloc] initWithArray:objects];

    }
    }];
    [self.myCollectionView reloadData];
}

Upvotes: 0

Views: 119

Answers (1)

Pipiks
Pipiks

Reputation: 2048

When you reload your collection view, you can't know if data are loaded.

So you must put your reload data in the completion block.

Upvotes: 2

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