How to Add a UINavigationBar Without a UINavigationBarController programmatically (supports large title animated also)

NavBarTestViewController.swift

class NavBarTestViewController: UIViewController, UINavigationBarDelegate, UIScrollViewDelegate {
    
    private let navBar: UINavigationBar = {
        let navBar = UINavigationBar()
        navBar.translatesAutoresizingMaskIntoConstraints = false
        return navBar
    }()
    
    private let vScrollView: UIScrollView = {
        let scrollView = UIScrollView(frame: .zero)
        scrollView.bounces = true
        scrollView.alwaysBounceVertical = true
        scrollView.alwaysBounceHorizontal = false
        scrollView.showsVerticalScrollIndicator = false
        scrollView.showsHorizontalScrollIndicator = false
        scrollView.contentInsetAdjustmentBehavior = .never
        scrollView.backgroundColor = .clear
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        return scrollView
    }()
    
    internal let bodyView: UIView = {
        let view = UIView(frame: .zero)
        view.backgroundColor = .clear
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    private let buttonsAction: Selector = {
        return #selector(handleButtonPress(_:))
    }()
    
    private lazy var settingsButton: UIBarButtonItem = {
        let icon = UIImage(named: "icon.cog.filled")?.withRenderingMode(.alwaysTemplate)
        let rightItem = UIBarButtonItem(image: icon, style: .plain, target: self, action: buttonsAction)
        rightItem.tintColor = UIColor(hexString: "#642F58")
        return rightItem
    }()
    
    private var oldValue = false

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = UIColor(hexString: "#FDEFF8")
        
        addSubViews()
        
        setupNavBar()
    }
    

    private final func setupNavBar() {
        
        navBar.delegate = self
        navBar.prefersLargeTitles = true
        navBar.barTintColor = UIColor(hexString: "#FEF5FB")
        navBar.titleTextAttributes = [
            .foregroundColor: UIColor(hexString: "#6A315A"),
            .font: Fonts.default.semibold.withSize(18)
        ]
        navBar.largeTitleTextAttributes = [
            .foregroundColor: UIColor(hexString: "#6A315A"),
            .font: Fonts.default.bold.withSize(30)
        ]
        
        let navigationItem = UINavigationItem(title: "Community")
        navigationItem.largeTitleDisplayMode = .always
        navBar.setItems([navigationItem], animated: false)
    }
    
    private final func addSubViews() {
        
        view.addSubview(navBar)
        view.addSubview(vScrollView)
        vScrollView.addSubview(bodyView)
        vScrollView.delegate = self
        
        NSLayoutConstraint.activate([
            
            navBar.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            navBar.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            navBar.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            navBar.heightAnchor.constraint(greaterThanOrEqualToConstant: Constants.navigationBarXdevicesHeight), // 44 point
            
            vScrollView.topAnchor.constraint(equalTo: navBar.bottomAnchor),
            vScrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            vScrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            vScrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            
            bodyView.topAnchor.constraint(equalTo: vScrollView.topAnchor),
            bodyView.leadingAnchor.constraint(equalTo: vScrollView.leadingAnchor),
            bodyView.trailingAnchor.constraint(equalTo: vScrollView.trailingAnchor),
            bodyView.bottomAnchor.constraint(equalTo: vScrollView.bottomAnchor),
            bodyView.widthAnchor.constraint(equalTo: vScrollView.widthAnchor)
        ])
        
        let bodyViewHeight = bodyView.heightAnchor.constraint(equalToConstant: 1500)
        bodyViewHeight.priority = UILayoutPriority(rawValue: 250)
        bodyViewHeight.isActive = true
    }
    
    func position(for bar: UIBarPositioning) -> UIBarPosition {
        .topAttached
    }

    @objc
    private final func handleButtonPress(_ sender: UIButton) {
        
        if sender == settingsButton {
            
            print("settingsButton")
            
        }
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        
        let needsToShowLargeTitle = scrollView.contentOffset.y <= 64
        if needsToShowLargeTitle != oldValue {
            navBar.items?.first?.largeTitleDisplayMode = needsToShowLargeTitle ? .always : .never
            navBar.items?.first?.rightBarButtonItem = needsToShowLargeTitle ? nil : settingsButton
            self.oldValue = needsToShowLargeTitle
            UIView.animate(withDuration: 0.25, animations: {
                self.navBar.layoutIfNeeded()
                self.view.layoutIfNeeded()
            })
        }
    }
}