#import "RVCollectionViewCell.h"
#import "RVCollectionViewLayout.h"

@interface RVViewController ()<UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
...

/* inits the layout object and sets it to your uicollectionview via setCollectionViewLayout: */

    [self.collectionView registerClass:[RVCollectionViewCell class] forCellWithReuseIdentifier:@"ItemIdentifier"];

    self.collectionViewLayout = [[RVCollectionViewLayout alloc] init];
    self.collectionViewLayout.superView = self.view;
    [self.collectionView setCollectionViewLayout:self.collectionViewLayout];

...

/* In cellForItemAtIndexPath:, return an instance of RVCollectionViewCell */

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    RVCollectionViewCell *cell = (RVCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"ItemIdentifier" forIndexPath:indexPath];
    cell.imageView = self.imagesArray[indexPath.item];
    return cell;
}