如何使用 swift 在 UITabBarController 中以编程方式添加选项卡

UPDATE SWIFT 5

通过编程方式创建一个UITabBarController的例子:

首先，我们创建UIViewControllers，这将是选项卡栏界面的每个选项卡的内容.对于这个例子，我们只创建一个非常简单的.

class Item1ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = UIColor.green
        self.title = "item1"
        print("item 1 loaded")
    }
}

现在，UITabBarController:

我们创建要在选项卡栏中显示的UIViewControllers的新实例.然后我们为我们创建的每个实例创建一个图标，然后我们创建一个数组，其中包含所有UIViewControllers个指定选项卡栏界面每个选项卡内容的元素.The order of the view controllers in the array corresponds to the display order in the tab bar

class DashboardTabBarController: UITabBarController, UITabBarControllerDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
        delegate = self
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        let item1 = Item1ViewController()
        let icon1 = UITabBarItem(title: "Title", image: UIImage(named: "someImage.png"), selectedImage: UIImage(named: "otherImage.png"))
        item1.tabBarItem = icon1
        let controllers = [item1]  //array of the root view controllers displayed by the tab bar interface
        self.viewControllers = controllers
    }

    //Delegate methods
    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
        print("Should select viewController: \(viewController.title ?? "") ?")
        return true;
    }
}