AppDelegate 不显示情节提要按钮

Question

我正在通过以下方式设置一个包含多个 ViewController 的 MainViewController：

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        let pageController = UIPageViewController(
            transitionStyle: UIPageViewControllerTransitionStyle.scroll,
            navigationOrientation: UIPageViewControllerNavigationOrientation.horizontal,
            options: nil
        )

        let navigationController = MainViewController(rootViewController: pageController)
        navigationController.view.backgroundColor = UIColor.white

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let leftView = storyboard.instantiateViewController(withIdentifier: "VC1")
        let middleView = storyboard.instantiateViewController(withIdentifier: "VC2")
        let rightView = storyboard.instantiateViewController(withIdentifier: "VC3")

        navigationController.viewControllerArray = [leftView, middleView, rightView]

        self.window!.rootViewController = navigationController
        self.window!.makeKeyAndVisible()

        return true
    }
}

我的 MainViewController 也有一个浮动按钮。我已经在故事板中添加了这个（见下图）。问题是按钮没有显示。我如何让它显示？ 我知道这个问题与我在 AppDelegate 中添加 MainViewController 的事实有关，但我不确定这是如何隐藏按钮的。

Answer 1

您不是从情节提要创建 MainViewController 实例，而是通过调用其初始化程序来创建它。这意味着不会加载任何情节提要元素

你需要这样的东西：

let navigationController = storyboard.instantiateViewController(withIdentifier: "Main")
navigationController.viewControllers = [pageController]