Documentation for collectionViews does not mention initializing the layout but it crashes when not set

[cwoloszynski]

Looking to understand how the layout should be initialized to use the collection view and suggest adding this to the documentation.

[wow-such-amazing]

Not sure, but I think, that when you create UICollectionView from code, then you need to create Layout manually. Like this

lazy var collectionView: UICollectionView = {
        let layout = CarouselFlowLayout()
        layout.scrollDirection = .horizontal
        layout.sideItemAlpha = 0.8
        layout.sideItemScale = 0.8
        layout.spacingMode = CarouselFlowLayoutSpacingMode.overlap(visibleOffset: spacing)

        let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
        collectionView.backgroundColor = UIColor.groupTableViewBackground
        addSubview(collectionView)
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        pinToEdges(subview: collectionView)
        return collectionView
    }()

[twof]

Yeah one thing of note is that it won't use the layout you provide programmatically. What you have to do is set up your director as a FlowCollectionDirector, and then make your layout configurations through that object. You have to give your collectionview a layout to start, so I just give it the default flow layout.

let trackListCollection: UICollectionView = {
    let layout = UICollectionViewFlowLayout()
    let collection = UICollectionView(frame: .zero, collectionViewLayout: layout)
    collection.backgroundColor = .yellow
    collection.translatesAutoresizingMaskIntoConstraints = false
    collection.accessibilityLabel = "trackListCollection"
    return collection
}()

var trackListCollectionDirector: FlowCollectionDirector


override init(frame: CGRect) {
    self.trackListCollectionDirector = FlowCollectionDirector(self.trackListCollection)
    self.trackListCollectionDirector.minimumLineSpacing = 10
    
    self.trackListCollectionDirector.register(adapter: self.trackAdapter)
    
    self.trackListCollectionDirector.add(models: self.tracks)
    self.trackListCollectionDirector.reloadData()
    
    super.init(frame: frame)
    
    registerCells()
    setupViews()
    setupConstraints()
}