CollectionViewFlowLayout Centered Cell

gistfile1.txt

@interface YANCollectionViewFlowLayout : UICollectionViewFlowLayout

@property (nonatomic, assign) CGFloat previousOffset;
@property (nonatomic, assign) NSInteger currentPage;

@end

@implementation YANCollectionViewFlowLayout

- (void) setupInitialContentOffset {
    self.previousOffset = self.collectionView.contentOffset.x;
    self.currentPage = self.previousOffset / (self.itemSize.width + self.minimumInteritemSpacing);
    CGFloat updatedOffset = (self.itemSize.width + self.minimumInteritemSpacing) * self.currentPage;
    self.previousOffset = updatedOffset;
    [self.collectionView setContentOffset:CGPointMake(updatedOffset, self.collectionView.contentOffset.y) animated:YES];
}

- (CGPoint)targetContentOffsetForProposedContentOffset:(CGPoint)proposedContentOffset withScrollingVelocity:(CGPoint)velocity {
    NSInteger pageOffset = proposedContentOffset.x / (self.itemSize.width + self.minimumInteritemSpacing);
    
    self.currentPage = pageOffset;
    
    // Update offset by using item size + spacing
    CGFloat updatedOffset = (self.itemSize.width + self.minimumInteritemSpacing) * self.currentPage;
    self.previousOffset = updatedOffset;
    
    return CGPointMake(updatedOffset, proposedContentOffset.y);
}
@end