How to set UICollectionViewCell Width and Height programmatically

Question

I am trying to implement a CollectionView. When I am using Autolayout, my cells won\'t change the size, but their alignment.

Now I would rather want to

Answer 1

#Absolutely simple way:

class YourCollection: UIViewController,
     UICollectionViewDelegate,
     UICollectionViewDataSource {

#You must add "UICollectionViewDelegateFlowLayout" or, there is no autocomplete:

class YourCollection: UIViewController,
     UICollectionViewDelegate,
     UICollectionViewDataSource,
     UICollectionViewDelegateFlowLayout {

#Type "sizeForItemAt...". You're done!

class YourCollection: UIViewController,
     UICollectionViewDelegate,
     UICollectionViewDataSource,
     UICollectionViewDelegateFlowLayout {
 
     func collectionView(_ collectionView: UICollectionView,
      layout collectionViewLayout: UICollectionViewLayout,
      sizeForItemAt indexPath: IndexPath) -> CGSize {
     
     return CGSize(width: 37, height: 63)
}

That's it.

Example, if you want "each cell fills the whole collection view":

     guard let b = view.superview?.bounds else { .. }
     return CGSize(width: b.width, height: b.height)