UICollectionViewCompositionalLayout: How do I create an item in a UICollectionView that fills the UICollectionView's safe area?

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Created Jan ’23

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I have a UICollectionViewController inside of a UINavigationController and when the collection view does not contain any data, I want to have a single item that fills the visible area of the collection view.

I'm using UICollectionViewCompositionalLayout and thought I would be able to do this with a group / item size that has a fractionalWidth and fractionalHeight of 1.0 like this:

let itemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .fractionalHeight(1.0))
let item = NSCollectionLayoutItem(layoutSize: itemSize)
let groupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .fractionalHeight(1.0))
let group = NSCollectionLayoutGroup.horizontal(layoutSize: groupSize, subitems: [item])
let section = NSCollectionLayoutSection(group: group)
let layout = UICollectionViewCompositionalLayout(section: section)

However, this does not respect the collection view's safe area insets, so the item is too tall and ends up scrolling:

Full Height Collection View Item.png

Is there a way to have the fractionalHeight take the collection view's safe area into account or some other way to have a single item that fills the collection view's safe area?

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Answer 1

rpwachowski OP

Feb ’23

You could use UICollectionView.backgroundView instead of placing that view in the compositional layout. The background view is automatically sized so you wouldn't have to worry about scrolling.

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