CollectionView show items paging circularly - ios

Question

I have a CollectionView with have 2 items.
CollectionView has pagingEnabled, I want to show them circularly like:
[1] 2 -> [2] 1 -> [1] 2 -> [2] 1
Is it possible to do this with CollectionView
My code:
extension HomeViewController: UICollectionViewDelegateFlowLayout {
func configureHeaderView() {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
layout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
headerView = UICollectionView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: headerHeight), collectionViewLayout: layout)
headerView?.backgroundColor = .blue
headerView?.isPagingEnabled = true
headerView?.isUserInteractionEnabled = true
headerView?.rx.setDelegate(self).addDisposableTo(disposeBag)
let nib = UINib(nibName: BannerCollectionViewCell.reuseIdentifier, bundle: nil)
headerView?.register(nib, forCellWithReuseIdentifier: BannerCollectionViewCell.reuseIdentifier)
headerView?.showsHorizontalScrollIndicator = false
tableView.tableHeaderView = headerView
if let headerView = headerView {
self.bannerItems.asObservable().bindTo(headerView.rx.items(cellIdentifier: BannerCollectionViewCell.reuseIdentifier, cellType: BannerCollectionViewCell.self)) {
row, banner, cell in
cell.banner = banner
}.addDisposableTo(disposeBag)
}
}
// MARK: UICollectionViewDelegateFlowLayout
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: UIScreen.main.bounds.width, height: headerHeight)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
}

Answer 1

Make use of UICollectionView's scrollToItemAtIndexPath method to move collectionView back to the first item if it reached the end and the user swiped right. Move the collectionView back to the last item if user swiped left from first item. You should set the animation property to false
func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView) {
// Calculate where the collection view should be at the right-hand end item
let offsetRight = collectionView.frame.size.width * CGFloat(yourDataArray.count)
if scrollView.contentOffset.x == offsetRight {
// user is scrolling to the right from the last item to the 'fake' item 1.
// reposition offset to show the 'real' item 1 at the left-hand end of the collection view
let newIndexPath = IndexPath(row: 1, section: 0)
collectionView.scrollToItem(at: newIndexPath, at: .left, animated: false)
} else if scrollView.contentOffset.x == 0 {
// user is scrolling to the left from the first item to the fake 'item N'.
// reposition offset to show the 'real' item N at the right end of the collection view
let newIndexPath = IndexPath(row: (yourDataArray.count-2), section: 0)
collectionView.scrollToItem(at: newIndexPath, at: .left, animated: false)
}
}