以编程方式将选项卡栏添加到ViewController

import UIKit

class MainViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建一个UITabBarController实例
        let tabBarController = UITabBarController()
        
        // 创建要添加到选项卡栏的子ViewController
        let viewController1 = UIViewController()
        viewController1.title = "选项卡1"
        viewController1.tabBarItem.image = UIImage(named: "tab1")
        
        let viewController2 = UIViewController()
        viewController2.title = "选项卡2"
        viewController2.tabBarItem.image = UIImage(named: "tab2")
        
        // 将子ViewController添加到UITabBarController的viewControllers数组中
        tabBarController.viewControllers = [viewController1, viewController2]
        
        // 将UITabBarController设置为主ViewController的根视图控制器
        self.addChild(tabBarController)
        self.view.addSubview(tabBarController.view)
        tabBarController.didMove(toParent: self)
    }
}