iOS如何在未选中选项卡栏的情况下实现选项卡栏视图控制器？

// 创建选项卡栏视图控制器
let tabBarController = UITabBarController()

// 创建多个视图控制器
let viewController1 = UIViewController()
let viewController2 = UIViewController()
let viewController3 = UIViewController()

// 将视图控制器添加到选项卡栏视图控制器的子视图控制器数组中
tabBarController.viewControllers = [viewController1, viewController2, viewController3]

// 为每个视图控制器设置图标和标题
viewController1.tabBarItem = UITabBarItem(title: "Tab 1", image: UIImage(named: "tab1"), tag: 0)
viewController2.tabBarItem = UITabBarItem(title: "Tab 2", image: UIImage(named: "tab2"), tag: 1)
viewController3.tabBarItem = UITabBarItem(title: "Tab 3", image: UIImage(named: "tab3"), tag: 2)

// 设置默认选中的选项卡
tabBarController.selectedIndex = 0

// 将选项卡栏视图控制器设置为应用程序的根视图控制器
window?.rootViewController = tabBarController