Distribution of free space between collection view cells

Question

I'm trying to use collection view as week days picker.

Height and width of cell are constant. I'd like to position cells to fill full collection view width. I've tried this but doesn't work for me:

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        let collectionWidth = collectionView.frame.width
        let freeSpace = collectionWidth - 210

        return freeSpace / 7
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: 30, height: 30)
    } 

Answer 1

You need

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    let collectionWidth = (collectionView.frame.width - numberOfItems * 30 ) / (numberOfItems - 1)
     return collectionWidth
}

where numberOfItems = array datasource count of the collection

---

You may need

return freeSpace / 6

instead of

return freeSpace / 7

as you need to divide by numOfelements - 1 which is the correct count of spaces between the 7 items