Number of elements in collection view in landscape mode - ios

Question

I have a collection view where 2 cells are being placed horizontally in portrait. In landscape mode I want 5 cells to be placed accordingly.
There is a method setItemSizeForCollectionView that defines my layout based on a device orientation.
It gets called in method configureCollectionView() which is called in viewDidLoad() and in viewWillTransition() when device gets rotated.
Views are created programmatically, so the size of the main view and its safeAreaInsets are not available in viewDidLoad.
I was thinking about subtracting those insets from the device size based on the orientation.
Any hint how can I achieve proper layout?
private func setItemSizeForCollectionView(layout: UICollectionViewLayout, with size: CGSize) {
guard let layout = layout as? UICollectionViewFlowLayout else { return }
var numberOfElementsHorizontally: CGFloat
if UIDevice.current.orientation.isPortrait {
numberOfElementsHorizontally = 2
layout.itemSize = CGSize(width: size.width / numberOfElementsHorizontally,
height: size.width / numberOfElementsHorizontally)
}
if UIDevice.current.orientation.isLandscape {
numberOfElementsHorizontally = 5
layout.itemSize = CGSize(width: size.width / numberOfElementsHorizontally,
height: size.width / numberOfElementsHorizontally)
}
}
private func configureCollectionView() {
let layout = UICollectionViewFlowLayout()
let width = UIScreen.main.bounds.width
let height = UIScreen.main.bounds.height
setItemSizeForCollectionView(layout: layout, with: CGSize(width: width, height: height))
layout.minimumInteritemSpacing = 0
layout.minimumLineSpacing = 0
layout.scrollDirection = .vertical
collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
collectionView.dataSource = self
collectionView.delegate = self
collectionView.register(CharacterCell.self, forCellWithReuseIdentifier: CharacterCell.reuseIdentifier)
}

Answer 1

This is a general purpose method for selecting how many cells per row you want in a collectionView:
func sizeForCell(itemsPerRow: Int)
{
return CGSize( width: bounds.width - (minimumInteritemSpacing * itemsPerRow) / itemsPerRow, height: 200)
}
EDIT: A bit more explanation, what we're doing here is setting the cell width to the collectionView's width, then dividing it by however many cells we want in the row, then removing some more width to leave for padding (number of items * padding amount).