如何保持控制器只在一个方向?

visibleViewController是导航堆栈的俯视图控制器或导航控制器提供的视图控制器。

因此,当您呈现第二个导航控制器时,第一个导航控制器将读取第二个导航控制器属性,该属性将传递回横向视图控制器的属性。

您需要使用的是topViewController。这样,设置仅限于视图控制器堆栈。

好吧,那么:

扔掉你的UINavigationControllerExtension。

更改您的Info.plist,以便我们只启动到肖像:

(删除第1项和第2项。)

在app delegate中,添加以下代码,以允许我们旋转到横向 启动:

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
    return .all
}

class ViewController: PortraitViewController, UINavigationControllerDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationController?.delegate = self
    }
    func navigationControllerSupportedInterfaceOrientations(_ navigationController: UINavigationController) -> UIInterfaceOrientationMask {
        return self.supportedInterfaceOrientations
    }
    @IBAction func showView(_ sender: Any) {
        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController2") as! ViewController2
        let nav = UINavigationController(rootViewController: vc)
        nav.delegate = vc
        present(nav, animated: true, completion: nil)
    }
}

在ViewController2中,按如下方式修复代码:

class ViewController2: LandscapeViewController, UINavigationControllerDelegate {
    func navigationControllerSupportedInterfaceOrientations(_ navigationController: UINavigationController) -> UIInterfaceOrientationMask {
        return self.supportedInterfaceOrientations
    }
    func navigationControllerPreferredInterfaceOrientationForPresentation(_ navigationController: UINavigationController) -> UIInterfaceOrientation {
        return self.preferredInterfaceOrientationForPresentation
    }
    @IBAction func dismiss(_ sender: Any) {
        dismiss(animated: true, completion: nil)
    }
}

现在,应用程序的行为符合要求。