以编程方式将选项卡添加到选项卡栏答案

【问题标题】：Programmatically add tab to tab bar以编程方式将选项卡添加到选项卡栏
【发布时间】：2016-12-30 19:45:52
【问题描述】：

我有一个带有UITabBarController 作为我的初始视图控制器的应用程序。

目前我正在 Storyboard 中做所有事情，但我想根据用户是否登录以编程方式将一个标签添加到标签栏。

我做了一个TestViewController 来测试一下。现在我有两个标签（如下图所示）。我想以编程方式将第三个选项卡定位在右侧。我将此代码放在我的 AppDelegate 的 didFinishLaunching 方法中。根据打印语句，视图控制器被添加到标签栏，但它没有出现在标签栏中，然后应用程序加载。

有什么建议吗？

    func addTabTEST() {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let tabController = storyboard.instantiateViewControllerWithIdentifier("RootTabController") as! UITabBarController
    let TestVC = storyboard.instantiateViewControllerWithIdentifier("TestViewController") as! TestViewController
    let icon = UITabBarItem(title: "test", image: nil, selectedImage: nil)
    TestVC.tabBarItem = icon

    print("TAB CONTROLLERS 1: \(tabController.viewControllers)")

    tabController.addChildViewController(TestVC)
    tabController.viewControllers![2] = TestVC

    print("TAB CONTROLLERS 2: \(tabController.viewControllers)")

}

【问题讨论】：

标签： ios swift uitabbarcontroller uitabbar

【解决方案1】：

    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
    let nav1 = UINavigationController()
    let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)

    let first: ViewController = mainStoryboard.instantiateViewControllerWithIdentifier("ViewController") as! ViewController
    nav1.viewControllers = [first]
    nav1.setNavigationBarHidden(true, animated: true)
    nav1.title = "first"

    let nav2 = UINavigationController()
    let second: SecondViewController = mainStoryboard.instantiateViewControllerWithIdentifier("SecondViewController") as! SecondViewController
    nav2.viewControllers = [second]
    nav2.setNavigationBarHidden(true, animated: true)
    nav2.title = "second"

    let nav3 = UINavigationController()
    let third: ThirdViewController = mainStoryboard.instantiateViewControllerWithIdentifier("ThirdViewController") as! ThirdViewController
    nav3.viewControllers = [third]
    nav3.setNavigationBarHidden(true, animated: true)
    nav3.title = "third"



    let tabController = UITabBarController()
    tabController.viewControllers = [nav1,nav2,nav3]
    tabController.selectedIndex = 0

    self.window!.rootViewController = tabController
    self.window?.makeKeyAndVisible()

【讨论】：

【解决方案2】：

这是给 swift 4 的

self.window = UIWindow(frame: UIScreen.main.bounds) let nav1 = UINavigationController() let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)

    let first = mainStoryboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
    nav1.viewControllers = [first]
    nav1.setNavigationBarHidden(true, animated: true)
    nav1.title = "first"

    let nav2 = UINavigationController()
    let second: HomeViewController = mainStoryboard.instantiateViewController(withIdentifier: "HomeViewController2") as! HomeViewController2
    nav2.viewControllers = [second]
    nav2.setNavigationBarHidden(true, animated: true)
    nav2.title = "second"

    let nav3 = UINavigationController()
    let third = mainStoryboard.instantiateViewController(withIdentifier: "HomeViewController3") as! HomeViewController3
    nav3.viewControllers = [third]
    nav3.setNavigationBarHidden(true, animated: true)
    nav3.title = "third"



    let tabController = UITabBarController()
    tabController.viewControllers = [nav1,nav2,nav3]
    tabController.selectedIndex = 0

    self.window!.rootViewController = tabController
    self.window?.makeKeyAndVisible()

【讨论】：

【解决方案3】：

如果您不想使用 UIStoryboard 并且如果您有三个名为 oneVC、twoVC 和 threeVC 的视图控制器，您可以使用（适用于 Swift 5.3 和 iOS 14.2）

        let window = UIWindow(frame: UIScreen.main.bounds)
        window.backgroundColor = .systemBackground
        self.window = window

        // Put image path if you want to have an image on your TabBar for this view controller
        self.oneVC?.tabBarItem = UITabBarItem(title: "One", image: nil, selectedImage: nil)
        self.twoVC?.tabBarItem = UITabBarItem(title: "Two", image: nil, selectedImage: nil)
        self.threeVC?.tabBarItem = UITabBarItem(title: "Three", image: nil, selectedImage: nil)

        let tabController = UITabBarController()
        tabController.viewControllers = [oneVC, twoVC, threeVC]
        tabController.selectedIndex = 0

        self.window!.rootViewController = tabController
        self.window?.makeKeyAndVisible()

【讨论】：