Image IO - iOS Core Animation - page 305

index inSection : 0 ];
UICollectionViewCell *cell =
[ self . collectionView cellForItemAtIndexPath :indexPath];
UIImageView *imageView = [cell. contentView . subviews lastObject ];
imageView. image = image;
});
});
//not loaded yet
return nil ;
}
- ( UICollectionViewCell *)collectionView:( UICollectionView *)collectionView
cellForItemAtIndexPath:( NSIndexPath *)indexPath
{
//dequeue cell
UICollectionViewCell *cell =
[collectionView dequeueReusableCellWithReuseIdentifier :@"Cell"
forIndexPath :indexPath];
//add image view
UIImageView *imageView = [cell. contentView . subviews lastObject ];
if (!imageView)
{
imageView = [[ UIImageView alloc ] initWithFrame :
cell. contentView . bounds ];
imageView. contentMode = UIViewContentModeScaleAspectFit ;
[cell. contentView addSubview :imageView];
}
//set or load image for this index
imageView. image = [ self loadImageAtIndex :indexPath. item ];
//preload image for previous and next index
if (indexPath. item < [ self . imagePaths count ] - 1 )
{
[ self loadImageAtIndex :indexPath. item + 1 ];
}
if (indexPath. item > 0 )
{
[ self loadImageAtIndex :indexPath. item - 1 ];
}