iOS 14导航栏标题不显示在以编程方式创建的UINavigationController中

iOS 14.2，当我试图用下面的代码片段以编程方式呈现NavigationController时

@objc private func handleClick() {
    let viewController = MyViewController()
    
    self.present(viewController, animated: true, completion: nil)
}

新控制器中的条标题将不会被渲染。我遗漏了什么吗

class MyViewController: UINavigationController {
    override func viewDidLoad() {
        super.viewDidLoad()

        self.title = "TEST" // NOT WORK
        self.navigationItem.title = "Title" // NOT WORK
    }
}

还尝试了下面的代码片段，将常规视图控制器嵌套到UINavigableController中，但标题仍然没有呈现

@objc private func handleHelpClick() {
    let innerVC = MyInnerViewController()
    innerVC.title = "TEST"
    let viewController = UINavigationController(rootViewController: innerVC)
    self.present(viewController, animated: true, completion: nil)
}

---

文件说：

导航控制器使用与导航堆栈上的视图控制器关联的UINavigationItem类的导航项对象实例动态构建导航栏的内容

因此，根据我的理解，您必须为UIViewController本身设置标题，而不是为UINavigationController设置标题

例如：

结果：

---

文件说：

导航控制器使用与导航堆栈上的视图控制器关联的UINavigationItem类的导航项对象实例动态构建导航栏的内容

因此，根据我的理解，您必须为UIViewController本身设置标题，而不是为UINavigationController设置标题

例如：

结果：

---

@芬贝尔在操场上的回答

import UIKit
import PlaygroundSupport

class MyViewController: UINavigationController {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

class ViewController: UIViewController {
    
    private lazy var button: UIButton = {
        let btn = UIButton()
        btn.translatesAutoresizingMaskIntoConstraints = false
        btn.setTitle("Display NavVC", for: .normal)
        btn.setTitleColor(.blue, for: .normal)
        btn.addTarget(self, action: #selector(displayNavVC), for: .touchDown)
        return btn
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        configureButton()
    }
    
    private func configureButton() {
        view.addSubview(button)
        NSLayoutConstraint.activate([
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        ])
    }
    
    @objc
    private func displayNavVC() {
        let vc = UIViewController()
        vc.title = "abc"
        let navigationVC = MyViewController(rootViewController: vc)
        
        self.present(navigationVC, animated: true, completion: nil)
    }
}

// Present the view controller in the Live View window
PlaygroundPage.current.liveView = ViewController()

---

@芬贝尔在操场上的回答

import UIKit
import PlaygroundSupport

class MyViewController: UINavigationController {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

class ViewController: UIViewController {
    
    private lazy var button: UIButton = {
        let btn = UIButton()
        btn.translatesAutoresizingMaskIntoConstraints = false
        btn.setTitle("Display NavVC", for: .normal)
        btn.setTitleColor(.blue, for: .normal)
        btn.addTarget(self, action: #selector(displayNavVC), for: .touchDown)
        return btn
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        configureButton()
    }
    
    private func configureButton() {
        view.addSubview(button)
        NSLayoutConstraint.activate([
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        ])
    }
    
    @objc
    private func displayNavVC() {
        let vc = UIViewController()
        vc.title = "abc"
        let navigationVC = MyViewController(rootViewController: vc)
        
        self.present(navigationVC, animated: true, completion: nil)
    }
}

// Present the view controller in the Live View window
PlaygroundPage.current.liveView = ViewController()

---

你能在ViewDidDisplay而不是viewdidload中尝试吗？@madara它的行为相同，而不是呈现标题。你能在ViewDidDisplay而不是viewdidload中尝试吗？@madara它的行为相同，而不是呈现标题。谢谢，我试过了，但它也没有呈现标题。非常感谢你的演示。让我再试试你的例子。试过提供的例子，它在操场上工作。谢谢，我试过了，但它也没有呈现标题。非常感谢你的演示。让我再试试你的例子。试过提供的例子，它在操场上有效。