ios - 如何防止 ARSCNView 在方向更改期间旋转

Question

我正在使用 ARKit，我希望允许用户在纵向和横向模式下使用该应用程序。除了 ARSCNView 之外，我希望所有 UI 控件都在方向更改时旋转。我试图将 sceneView 变换到相反的方向，但没有成功。

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)

        let targetRotation = coordinator.targetTransform
        let inverseRotation = targetRotation.inverted()

        coordinator.animate(alongsideTransition: { (context) in
            self.sceneView.transform = self.sceneView.transform.concatenating(inverseRotation)
            context.viewController(forKey: UITransitionContextViewControllerKey.from)
        }, completion: nil)

    }

如何防止 ARKit session 的场景 View 旋转，同时允许所有其他 UI 控件在方向更改时旋转？

Answer 1

您不能在 View 基础上指定设备旋转规则。它必须在 View Controller 的基础上设置。这就是 iOS 的工作原理。因此，要实现您的需要，您必须自己处理。例如，如果您将 ARSCNView 显示为全屏 View ，则可以在自定义 UIViewController 子类中显示它，并为其设置旋转配置 Controller 。

为特定 View Controller 设置支持的 View 旋转可以通过多种方式实现，下面是其中的一些。

---

方法#1:

您可以通过重写应用委托(delegate)的方法 application:supportedInterfaceOrientationsForWindow: 为任何 UIViewController 设置支持的 View 方向。

示例代码:

// this goes into your AppDelegate...
// Basically, this checks the current visible view controller  type  and  decide 
// what orientations your app supports based on that view controller type (class)
func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
    let visibleViewController = self.topViewController(withRootViewController: window?.rootViewController)

    // Support only portrait orientation for a specific view controller
    if visibleViewController is SomeViewController {
        return .portrait
    }

    // Otherwise, support all orientations (standard behaviour)
    return .allButUpsideDown
}

// This simple helper method is to extract the exact visible  view  controller  at
// the moment, as `window.rootViewController` could have some container controller 
// like `UINavigationController` or so that holds more controllers into it
private func topViewController(withRootViewController rootViewController: UIViewController?) -> UIViewController? {
    if let rootViewController = rootViewController as? UITabBarController {
        return rootViewController.selectedViewController
    } else if let rootViewController = rootViewController as? UINavigationController {
        return rootViewController.visibleViewController
    } else if let presentedViewController = rootViewController?.presentedViewController {
        return topViewController(withRootViewController: presentedViewController)
    }
    return rootViewController
}

引用:

application:supportedInterfaceOrientationsForWindow: method documentation

---

方法 #2:

子类化您的 UINavigationController 并覆盖以下属性:

override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    return self.topViewController?.supportedInterfaceOrientations ?? .all
}

现在这总是查看您的 View Controller 的 supportedInterfaceOrientations 并根据返回值设置支持的方向。这样做可以让您在任何您想要的 View Controller 中简单地覆盖它，设置一些自定义值。

例如，在 SomeViewController 中，您可以简单地添加:

override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    return .portrait
}

引用:

supportedInterfaceOrientations property documentation

---

方法#3:

如果您不想像上面的方法 #2 那样子类化您的 UINavigationController，您可以将您的 SomeViewController 设置为实现 的导航 Controller 委托(delegate)navigationControllerSupportedInterfaceOrientations(:)

示例代码:

override func viewDidLoad() {
    super.viewDidLoad()

    // ...

    self.navigationController?.delegate = self
}

// MARK: - UINavigationControllerDelegate

func navigationControllerSupportedInterfaceOrientations(_ navigationController: UINavigationController) -> UIInterfaceOrientationMask {
    return navigationController.topViewController?.supportedInterfaceOrientations ?? .all
}

引用:

Matt's answer here