swift - 为什么在第一次启动时我的导航栏在状态栏下面

Question

为什么当我用空 View Controller 创建导航 Controller 时，我收到导航栏的奇怪行为？

这就是我创建导航 Controller 的方式。

init(
    window: UIWindow,
    keystore: Keystore,
    navigationController: UINavigationController = UINavigationController()
) {
    self.navigationController = navigationController
    self.keystore = keystore
    super.init()
    window.rootViewController = navigationController
    window.makeKeyAndVisible()
}

比我更简单:

func start() {
    let x = UIViewController()
    x.view.backgroundColor = UIColor.red
    navigationController.setViewControllers([x], animated: true)
}

我收到: 但在下一次应用启动时一切正常。

Answer 1

可能是这种情况，因为您在应用已经启动后设置了 NavigationController。

我建议在您的 AppDelegate 中设置 NavigationController。

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        window = UIWindow(frame: UIScreen.main.bounds)

        let firstViewController = UIViewController()
        let navigationController = UINavigationController(rootViewController: firstViewController)

        window?.rootViewController = navigationController
        window?.makeKeyAndVisible()
        return true
    }
}