Swift 5.6 NavigationItem不显示

Question

我正在尝试将ImageView添加到NavigationBar。我在SceneDelegate中进行了所有设置，以设置一个rootviewController，并且似乎有效，但是当我尝试添加标题或图像时，它确实没有显示。

SceneDelegate：

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        
        guard let scene = (scene as? UIWindowScene) else { return }
        window = UIWindow(windowScene: scene)
        window?.rootViewController = UINavigationController(rootViewController: MainTabController())
        window?.makeKeyAndVisible()
    }

navigationbar NavigationController：

class FeedController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        configureUI()
        setupNavController()
    }
    
    func configureUI() {
        view.backgroundColor = .white

        let imageView = UIImageView(image: UIImage(named: "twitter_logo_blue"))
        imageView.contentMode = .scaleAspectFit
        navigationItem.titleView = imageView
   
    }
    
    @objc func addTapped() {
        //
    }
    
    func setupNavController() {
        if #available(iOS 15.0, *) {
            let navigationBarAppearance = UINavigationBarAppearance()
            navigationBarAppearance.configureWithDefaultBackground()
            UINavigationBar.appearance().standardAppearance = navigationBarAppearance
            UINavigationBar.appearance().compactAppearance = navigationBarAppearance
            UINavigationBar.appearance().scrollEdgeAppearance = navigationBarAppearance
        }
    }
}

Answer 1

请勿在uinavigationController中嵌入uitabbarController。宁愿将每个uiviewController嵌入uinavigationController之前，然后将它们添加到uitabbarcontroller。这是一个例子。

修改场景（_：willconnectto：options）方法如下。

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    guard let windowScene = (scene as? UIWindowScene) else { return }
    
    let window = UIWindow(windowScene: windowScene)
    window.rootViewController = MainTabViewController()
    self.window = window
    window.makeKeyAndVisible()
}

这是MainterabbarController类。

class MainTabViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let mainVC = UINavigationController(rootViewController: ViewController())
        mainVC.tabBarItem = UITabBarItem(title: "Tab 1", image: UIImage(systemName: "circle"), selectedImage: UIImage(systemName: "circle.fill"))
        let secondVC = UINavigationController(rootViewController: SecondViewController())
        secondVC.tabBarItem = UITabBarItem(title: "Tab 2", image: UIImage(systemName: "square"), selectedImage: UIImage(systemName: "square.fill"))
        
        viewControllers = [mainVC, secondVC]
    }
}

现在，navigationItem在uiviewController中修改titleView navigationItem 。

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        configureUI()
        setupNavController()
    }
    
    func configureUI() {
        view.backgroundColor = .white
        
        let imageView = UIImageView(image: UIImage(systemName: "sun.max.circle.fill"))
        imageView.contentMode = .scaleAspectFit
        navigationItem.titleView = imageView
        
    }
    
    func setupNavController() {
        if #available(iOS 15.0, *) {
            
            let navigationBarAppearance = UINavigationBarAppearance()
            navigationBarAppearance.configureWithDefaultBackground()
            UINavigationBar.appearance().standardAppearance = navigationBarAppearance
            UINavigationBar.appearance().compactAppearance = navigationBarAppearance
            UINavigationBar.appearance().scrollEdgeAppearance = navigationBarAppearance
        }
    }
}