Setting size of UICollectionViewCell in a way that there is no interim spacing in between

Question

I\'m using an UICollectionView on which I want to place seven cells side by side. The whole screen should be used for this. Currently, I\'m using the width of the c

Answer 1

As you already figured out it's impossible to divide a 320 point wide screen into 7 equal portions.

But if a cell is a half or even one point larger or smaller than another one nobody will notice. You can use a little bit of math to get integer pixel values (i.e. 0.5 points).

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
    var size: CGSize!
    let column = indexPath.item % 7
    let width = collectionView.bounds.size.width
    let height = 80.0

    if width == 320.0 {
        // iPhone 5
        // 46 + 0,5 + 45 + 0,5 + 45 + 0,5 + 45 + 0,5 + 45 + 0,5 + 45 + 0,5 + 46
        if column == 0 || column == 6 {
            size = CGSize(width: 46, height: height)
        }
        else {
            size = CGSize(width: 45, height: height)
        }
    }
    else if width == 375.0 {
        // iPhone 6
        // 53 + 0,5 + 53 + 0,5 + 53 + 0,5 + 54 + 0,5 + 53 + 0,5 + 53 + 0,5 + 53
        if column == 3 {
            size = CGSize(width: 54, height: height)
        }
        else {
            size = CGSize(width: 53, height: height)
        }
    }
    else if width == 414.0 {
        // iPhone 6 Plus
        // 58 + 0,5 + 59 + 0,5 + 59 + 0,5 + 59 + 0,5 + 59 + 0,5 + 59 + 0,5 + 58
        if column == 0 || column == 6 {
            size = CGSize(width: 58, height: height)
        }
        else {
            size = CGSize(width: 59, height: height)
        }
    }
    else {
        println("Unhandled Width: \(width)")
        abort()
    }
    return size
}

That's just an example, that I had ready because I am currently working on a calendar view. It has a 1 pixel spacing between each cell. For a 320 pt wide cell layout without spacing you could use something like 45.5+45.5+46+46+46+45.5+45.5