How to center the first and the last cell of a horizontal UICollectionView?

Question

I'm trying to center the first and the last cell of a horizontal collection view.

The only approach i found until now was adding extra cells at the begin and the end of my UICollectionView. This method was totally a bad idea for obvious reasons but I didn't find a better way to do it for now. And since, with the iPhone 6 and the iPhone 6+, the layout of my view is totally broken... (facepalm)

To illustrate my need I need to display something like this :

|        x x x x x|  where the first x represent my first cell

and

|x x x x x        |  where the last x represent my last cell

I think using a UICollectionViewFlowLayout subclass is the proper way to do that with contentInset stuff but I'm a total newbie with these components.
Any links or suggestions on how to achieve this ?

T. Hyldgaard · Accepted Answer · 2017-05-10T08:54:20.173

Posting here for future reference, as I've been working with same problem, and found a solution. Tested in Xcode Version 8.2.1 (8C1002) with Swift 3

The UICollectionViewDelegate has the func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets

To center the first and last cell in the collection view, your calculate the inset by:

let inset: CGFloat = collectionView.frame.width * 0.5 - cellSize.width * 0.5

After this, you simply return the new UIEdgeInsetMake(0, inset, 0, inset)

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    let inset: CGFloat = collectionView.frame.width * 0.5 - cellSize.width * 0.5
    return UIEdgeInsetsMake(0, inset, 0, inset)
}

-------Edit-------

In this case I store the cell size as a hard coded value, and set it by using the delegate func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize

if scrolling is enabled, how can we center scrolling item? – S.Hoseinpoor Dec 23 '18 at 13:17 — S.Hoseinpoor, Dec 23 '18 at 13:17

score 0 · Answer 2 · answered Aug 02 '18 at 04:51

Easy handle for your different sections.

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    return UIEdgeInsetsMake(0, collectionView.frame.size.width/2, 0, collectionView.frame.size.width/2);
}

How to center the first and the last cell of a horizontal UICollectionView?

2 Answers2