CatsUIView Sample

CatsUIView.swift

class CatsUIView: UIView {
    private var catsView: CatsView?
    private var hostingViewController: UIViewController?
    
    ...
 
    override func didMoveToSuperview() {
        super.didMoveToSuperview()
        guard hostingViewController == nil else { return }
        
        let catsView = CatsView(.init(onSizeChange: { [weak self] in
            self?.invalidateIntrinsicContentSize() // #5
        }))
        self.catsView = catsView
        hostingViewController = UIHostingController(rootView: catsView) // #1
        
        guard let embeddedCatsView = hostingViewController?.view else { return }
        
        // Pin view to edges of hosting view
        embeddedCatsView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(embeddedCatsView) // #2
        [
            embeddedCatsView.topAnchor.constraint(equalTo: topAnchor),
            embeddedCatsView.bottomAnchor.constraint(equalTo: bottomAnchor),
            embeddedCatsView.leadingAnchor.constraint(equalTo: leadingAnchor),
            embeddedCatsView.trailingAnchor.constraint(equalTo: trailingAnchor)
        ].forEach { $0.isActive = true } // #3
        ...
    }
override var intrinsicContentSize: CGSize {
        return hostingViewController?.view.intrinsicContentSize ?? .zero // #4
    }
}