以编程方式在UIViewController中添加UINavigationController

在UIViewController中以编程方式添加UINavigationController，可以通过以下步骤实现：

首先，在UIViewController中导入UINavigationController头文件。

import UIKit

class YourViewController: UIViewController {
    // Your view controller code
}

创建一个UINavigationController实例，并将当前UIViewController实例作为其根视图控制器。

import UIKit

class YourViewController: UIViewController {
    // Your view controller code

    func addNavigationController() {
        let navigationController = UINavigationController(rootViewController: self)
        // Customize the navigation controller if needed
    }
}

将UINavigationController的视图添加到当前UIViewController的视图中。

import UIKit

class YourViewController: UIViewController {
    // Your view controller code

    func addNavigationController() {
        let navigationController = UINavigationController(rootViewController: self)
        // Customize the navigation controller if needed

        // Add the navigation controller's view to the current view controller's view
        addChild(navigationController)
        view.addSubview(navigationController.view)
        navigationController.didMove(toParent: self)
    }
}

在viewDidLoad()方法中调用addNavigationController()方法。

import UIKit

class YourViewController: UIViewController {
    // Your view controller code

    override func viewDidLoad() {
        super.viewDidLoad()

        addNavigationController()
    }

    func addNavigationController() {
        let navigationController = UINavigationController(rootViewController: self)
        // Customize the navigation controller if needed

        // Add the navigation controller's view to the current view controller's view
        addChild(navigationController)
        view.addSubview(navigationController.view)
        navigationController.didMove(toParent: self)
    }
}

现在，当您运行应用程序时，您的UIViewController将以编程方式包含一个UINavigationController。