Ios 如何在Swift中实现自定义NavigationController_Ios_Swift_Uinavigationcontroller_User Profile

Ios 如何在Swift中实现自定义NavigationController

ios swift

Ios 如何在Swift中实现自定义NavigationController,ios,swift,uinavigationcontroller,user-profile,Ios,Swift,Uinavigationcontroller,User Profile,我有一个应用程序，它使用NavigationController和TabBarController在不同的视图中轻松导航。对于某些视图，我有一个标题和一些按钮（有时只在右侧，有时在右侧和左侧）。但是，对于某些视图，例如在观看某人的个人资料时，我不想设置标题。我想显示个人资料图片，并在图片下方添加用户名我的问题很简单：我是否应该使用NavigationController来实现这一点，因为我希望配置文件图片“覆盖”NavigationController，使其与状态栏的距离仅为16像素，而不是与

我有一个应用程序，它使用NavigationController和TabBarController在不同的视图中轻松导航。对于某些视图，我有一个标题和一些按钮（有时只在右侧，有时在右侧和左侧）。但是，对于某些视图，例如在观看某人的个人资料时，我不想设置标题。我想显示个人资料图片，并在图片下方添加用户名

我的问题很简单：我是否应该使用NavigationController来实现这一点，因为我希望配置文件图片“覆盖”NavigationController，使其与状态栏的距离仅为16像素，而不是与NavigationController的距离。在仍然有左键和右键的情况下，这是可能的（例如，编辑您自己的配置文件，或者编辑“更多选项”按钮）

我一直在考虑使用一种完全不同的方法，不使用NavigationController，而是在必要时使用标签来显示标题，并在左侧和右侧添加视图，以便在必要时添加按钮

由于这是我第一次做这样的事情，我很想听听你对如何实现这一结果以及最佳实践的看法。有些事情告诉我，最好使用NavigationController，因为这就是它的目的，但是我如何实现可选标题并在需要时检查它呢？我已经知道如何去除底部发际线以及如何相应地设置背景色，所以这不是最大的问题。我只关心如何在NavigationController上显示图像

谢谢大家

创建自定义“标题标签”的最佳方法是对

UIView

和

UINavigationController

进行子类化。这方面的演示是

主要部件包括导航控制器。基本上，您希望将

title

属性保留为空（一个空字符串或不设置它），并且由于

UINavigationController

只是

UIViewController

的一个子类，作为具有push/pop功能的容器视图工作，因此可以以这种方式使用您的子类。在我的演示中，我的子类nav控制器类被称为

NavigationController

在我看来，您从子类化

UINavigationController

中获得的主要优势是使用它的push/pop功能。。。虽然你可以使用segues，但它们需要一个故事板，虽然你可以使用

UIView

动画，但我觉得它并不“流畅”

（1）如果您没有使用情节提要，请记住在
AppDelegate
：

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}

（2）虽然还有其他方法可以做到这一点，但我更喜欢在我的子类中实例化视图控制器，根据需要将方法公开给push/pop:

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}

（3）在其他VCs中，根据需要设置左/右按钮，并根据需要按下/弹出。我喜欢使用UTF-8字符的自定义“箭头”：

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}

请注意，我强制转换视图的

naviagtionController？

属性作为我的子类类型。需要强制转换才能访问其中的自定义方法

（4）下一步，包括您自定义的“标题视图”。为了演示，我创建了一个50/50的黄色/蓝色。请注意，它使用自动布局锚定：

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}

（5）在导航控制器的初始化中，添加代码以添加标题视图。请注意，我将自动布局与两个东西一起使用。首先，我将宽度设置为状态栏宽度的1/3。您可以进行实验-对于图像，您最好设置一个恒定的宽度。其次，请注意名为

titleViewHeightConstraint

的“命名”约束的用法。我将在下一步解释这一点

titleViewHeightConstraint = titleView.heightAnchor.constraint(equalToConstant: 0)
titleViewHeightConstraint.isActive = true
titleView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
titleView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
titleView.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.3).isActive = true

（5）动态调整标题标签的高度：

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}

请记住，

UINavigationController

实际上是一个容器视图控制器。它的“根”视图是全屏的，所以如果你将标题标签锚定到底部，你会得到一个从上到下的垂直大小的标签。更糟糕的是，有时会有一个状态栏，尤其是在肖像中。但其他时候（默认情况下）并非如此。因此，我使用导航控制器（检测是否存在状态栏）和视图控制器（检测导航栏和状态栏的高度）的

safeAreaLayoutGuide

（5a）将此方法添加到导航控制器：

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}

（5b）并将此覆盖添加到子类导航控制器内的所有视图控制器：

var navController: NavigationController?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    navController = NavigationController(nibName: nil, bundle: nil)
    self.window!.rootViewController = navController
    self.window?.makeKeyAndVisible()
    return true
}

class NavigationController:UINavigationController {

    let redVC = RedViewController()
    let greenVC = GreenViewController()
    let titleView = TitleView()
    var titleViewHeightConstraint:NSLayoutConstraint!

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
        pushViewController(redVC, animated: false)  // display the first VC
    }
    func popGreenVC() {
        popViewController(animated: true)
    }
    func pushGreenVC() {
        pushViewController(greenVC, animated: true)
    }
}

class RedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.red
        let showGreenVC = UIBarButtonItem(title: "Green \u{25B6}", style: .plain, target: self, action: #selector(pushGreenVC))
        self.navigationItem.rightBarButtonItem = showGreenVC
    }
    @objc func pushGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.pushGreenVC()
    }
}

class GreenViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.green
        let showRedVC = UIBarButtonItem(title: "\u{25C0} Red", style: .plain, target: self, action: #selector(popGreenVC))
        self.navigationItem.leftBarButtonItem = showRedVC
    }
    @objc func popGreenVC() {
        let navController = self.navigationController as! NavigationController
        navController.popGreenVC()
    }
}

class TitleView: UIView {
    let yellowView = UIView()
    let blueView = UIView()
    convenience init() {
        self.init(frame: CGRect.zero)

        self.translatesAutoresizingMaskIntoConstraints = false
        yellowView.translatesAutoresizingMaskIntoConstraints = false
        blueView.translatesAutoresizingMaskIntoConstraints = false

        yellowView.backgroundColor = UIColor.yellow
        blueView.backgroundColor = UIColor.blue
        self.addSubview(yellowView)
        self.addSubview(blueView)

        yellowView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        yellowView.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
        yellowView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        yellowView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        blueView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        blueView.leadingAnchor.constraint(equalTo: yellowView.trailingAnchor).isActive = true
        blueView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 0.5).isActive = true
        blueView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
}

func changeTitleViewHeight(to:CGFloat) {
    titleViewHeightConstraint.constant = to - view.safeAreaInsets.top
}

override func viewSafeAreaInsetsDidChange() {
    let navController = self.navigationController as! NavigationController
    navController.changeTitleViewHeight(to: view.safeAreaInsets.top)
}