仅在一个ViewController中旋转

Question

我试图旋转一个视图，而所有其他视图（5）都固定为纵向。原因是，在这一视图中，我希望用户观看他之前保存的图片。我想这是可能的，但到目前为止我还不知道如何做到这一点。有谁能帮我或给我一个提示吗？我正在用iOS8上的Swift进行编程

Answer 1

有时，当您使用自定义导航流（可能会变得非常复杂）时，上述解决方案可能并不总是有效。此外，如果您有几个需要支持多个方向的ViewController，它可能会变得非常乏味。

这是我找到的一个相当快速的解决方案。定义一个类OrientationManager并使用它来更新AppServer中支持的方向：

class OrientationManager {
    static var landscapeSupported: Bool = false
}

然后将您想要的特定情况下的方向：

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
        if OrientationManager.landscapeSupported {
            return .allButUpsideDown
        }
        return .portrait
    }

然后，在要进行多个导航的视图控制器中，更新方向管理器：

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    OrientationManager.landscapeSupported = true
}

此外，在退出此ViewController时，不要忘记再次更新它：

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    OrientationManager.landscapeSupported = false
    //The code below will automatically rotate your device's orientation when you exit this ViewController
    let orientationValue = UIInterfaceOrientation.portrait.rawValue
    UIDevice.current.setValue(orientationValue, forKey: "orientation")
}

希望这有帮助！

更新：

您可能只想将静态func添加到您的方向支持管理器类：

    static func setOrientation(_ orientation: UIInterfaceOrientation) {
        let orientationValue = orientation.rawValue
        UIDevice.current.setValue(orientationValue, forKey: "orientation")
        landscapeSupported = orientation.isLandscape
    }

然后，您可以在需要将方向设置回纵向时调用此函数。这也将更新静态的landscapeSupported值：

OSM.setOrientation(.portrait)

Answer 2

您也可以以面向协议的方式执行此操作。只需创建协议

protocol CanRotate {

}

以更“迅速”的方式在AppServer ate中添加相同的2个方法

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
    if topViewController(in: window?.rootViewController) is CanRotate {
        return .allButUpsideDown
    } else {
        return .portrait
    }
}


func topViewController(in rootViewController: UIViewController?) -> UIViewController? {
    guard let rootViewController = rootViewController else {
        return nil
    }

    if let tabBarController = rootViewController as? UITabBarController {
        return topViewController(in: tabBarController.selectedViewController)
    } else if let navigationController = rootViewController as? UINavigationController {
        return topViewController(in: navigationController.visibleViewController)
    } else if let presentedViewController = rootViewController.presentedViewController {
        return topViewController(in: presentedViewController)
    }
    return rootViewController
}

在每个需要不同行为的ViewController中，只需在类的定义中添加协议名称。

class ViewController: UIViewController, CanRotate {}

如果需要任何特定的组合，可以向协议中添加一个变量以覆盖

protocol CanRotate {
    var supportedInterfaceOrientations: UIInterfaceOrientationMask
}

Answer 3

我建议在您的appDelegate中使用SupportedInterfaceDirectionsforWindow，以仅允许在特定视图控制器中旋转，例如：

Swift 4/Swift 5

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

    // Make sure the root controller has been set
    // (won't initially be set when the app is launched)
    if let navigationController = self.window?.rootViewController as? UINavigationController {

        // If the visible view controller is the
        // view controller you'd like to rotate, allow
        // that window to support all orientations
        if navigationController.visibleViewController is SpecificViewController {
            return UIInterfaceOrientationMask.all
        } 

        // Else only allow the window to support portrait orientation
        else {
            return UIInterfaceOrientationMask.portrait
        }
    }

    // If the root view controller hasn't been set yet, just
    // return anything
    return UIInterfaceOrientationMask.portrait
}

请注意，如果在转到纵向屏幕之前，SpecificViewController处于横向，则另一个视图仍将在横向中打开。为了避免这种情况，我建议在视图处于横向时不允许过渡。

雨燕3

func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> Int {

    // Make sure the root controller has been set
    // (won't initially be set when the app is launched)
    if let navigationController = self.window?.rootViewController as? UINavigationController {

        // If the visible view controller is the
        // view controller you'd like to rotate, allow
        // that window to support all orientations
        if navigationController.visibleViewController is SpecificViewController  {
            return Int(UIInterfaceOrientationMask.All.rawValue)
        }

        // Else only allow the window to support portrait orientation
        else {
            return Int(UIInterfaceOrientationMask.Portrait.rawValue)
        }
    }

    // If the root view controller hasn't been set yet, just
    // return anything
    return Int(UIInterfaceOrientationMask.Portrait.rawValue)
}