Ios setNavigationBarHidden未以编程方式工作？

我试图以编程方式创建不同的视图控制器，其中第一个视图控制器不应显示导航栏，而第二个视图控制器应显示导航栏。我似乎无法让第二个视图控制器显示导航栏。所有的代码编译得很好，按下控制器的按钮工作，因为第二个屏幕会变成绿色

以下是AppDelegate：

class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    window = UIWindow(frame: UIScreen.main.bounds)
    window?.makeKeyAndVisible()

    let layout = UICollectionViewFlowLayout()
    let startupScreenController = StartupScreenController(collectionViewLayout: layout)
    window?.rootViewController = UINavigationController(rootViewController: startupScreenController)

    application.statusBarStyle = .lightContent

    return true
}

以下是第一个视图控制器：

func skipButtonPressed() {

    let layout = UICollectionViewFlowLayout()
    let secondViewController = SecondViewController(collectionViewLayout: layout)
    self.navigationController?.pushViewController(secondViewController, animated: true)

}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // Hide the navigation bar on this view controller
    self.navigationController?.setNavigationBarHidden(true, animated: animated)
}

class SecondViewController: UICollectionViewController {

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    // Show the Navigation Bar on this view controller

    self.navigationController?.setNavigationBarHidden(false, animated: animated)
    UINavigationBar.appearance().barTintColor = UIColor(red: 24/255, green: 24/255, blue: 24/255, alpha: 1  )
}

override func viewDidLoad() {
    super.viewDidLoad()

    collectionView?.backgroundColor = UIColor.green

}

这是第二个视图控制器：

func skipButtonPressed() {

    let layout = UICollectionViewFlowLayout()
    let secondViewController = SecondViewController(collectionViewLayout: layout)
    self.navigationController?.pushViewController(secondViewController, animated: true)

}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // Hide the navigation bar on this view controller
    self.navigationController?.setNavigationBarHidden(true, animated: animated)
}

class SecondViewController: UICollectionViewController {

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    // Show the Navigation Bar on this view controller

    self.navigationController?.setNavigationBarHidden(false, animated: animated)
    UINavigationBar.appearance().barTintColor = UIColor(red: 24/255, green: 24/255, blue: 24/255, alpha: 1  )
}

override func viewDidLoad() {
    super.viewDidLoad()

    collectionView?.backgroundColor = UIColor.green

}

---

您可以直接在ViewDidLoad中使用该导航条形码

  override func viewDidLoad() {

  self.navigationController?.setNavigationBarHidden(false, animated: 
   animated)
   }

---

你必须像下面这样做

func viewDidLoad() {
    super.viewDidLoad()
    self.navigationController?.setNavigationBarHidden(false, animated: animated)
}

---

按以下方式隐藏

导航栏

。设置

false

以启用返回

override func viewDidLoad() {  
    super.viewDidLoad()
    self.navigationController?.navigationBar.isHidden = true
}

---

对于我的项目，它只有在我将其添加到viewWillLayoutSubviews（）中时才起作用

---

别忘了添加call

super.viewDidLoad（）

根据stackoverflow指南，您应该接受正确答案，以便其他人在遇到相同问题时获得帮助@unicorn_惊讶这不会编译，因为

动画

没有在任何地方声明。