与导航控制器一起使用时不显示 UITabBarItem 的标题

Question

我在使用非常简单的应用程序时遇到了问题。

我的应用程序只有 2 个主要 UIViewControllers，分别称为新闻和类别，每个都有自己的 UINavigationController。

所以在AppDelegate.swift，我是这样做的

window = UIWindow(frame: UIScreen.main.bounds)
let tabBarController = UITabBarController()

let newsVC = NewsVC()

// CREATE TAB BAR ITEM WITH TITLE ONLY
let newsVCTabBarItem = UITabBarItem(title: "News", image: nil, tag: 1)
newsVC.tabBarItem = newsVCTabBarItem

let categoryVC = CategoryVC()

// CREATE TAB BAR ITEM WITH TITLE ONLY
let categoryVCTabBarItem = UITabBarItem(title: "Category", image: nil, tag: 2)
categoryVC.tabBarItem = categoryVCTabBarItem

let rootViewControllers = [newsVC, categoryVC]

// CREATE NAVIGATION CONTROLLER FOR EACH OF THEM
tabBarController.viewControllers = rootViewControllers.map {
    UINavigationController(rootViewController: [=10=])
}
window?.rootViewController = tabBarController
window?.makeKeyAndVisible()

当我运行这个简单的应用程序时，标签栏项目不显示任何内容:(

但是当我将 UITabBarItem 更改为这样的系统样式时

let newsVCTabBarItem = UITabBarItem(tabBarSystemItem: .featured, tag: 1)

一切正常！太难懂了！

那么有人知道为什么我的 title-only 标签栏项目不起作用吗？我错过了什么重要的事情吗？

提前致谢！

Answer 1

将 title 属性添加到 ViewController 以在 UITabBarItem 中显示标题。

var title: String? { get set }

Set the title to a human-readable string that describes the view. If the view controller has a valid navigation item or tab-bar item, assigning a value to this property updates the title text of those objects.

let newsVC = ViewController()
newsVC.title = "News"

.....

let categoryVC = ViewController2()
categoryVC.title = "Category"

.....

或者

将图像分配给 UITabBarItem 以查看结果。

let newsVCTabBarItem = UITabBarItem(title: "News", image: UIImage(named: "news.png"), tag: 1)

....

let categoryVCTabBarItem = UITabBarItem(title: "Category", image: UIImage(named: "category.png"), tag: 2)

.....

更新：

Tab bar items are configured through their corresponding view controller. To associate a tab bar item with a view controller, create a new instance of the UITabBarItem class, configure it appropriately for the view controller, and assign it to the view controller’s tabBarItem property. If you don't provide a custom tab bar item for your view controller, the view controller creates a default item containing no image and the text from the view controller’s title property.

与导航控制器一起使用时不显示 UITabBarItem 的标题

UITabBarItem's title does not shown when using with Navigation controller

uitabbarcontroller

uitabbaritem

ios

swift