从其他屏幕返回时,屏幕从纵向旋转到lanscape

这里- https://stackoverflow.com/a/41811798/10261915 你有答案

struct AppUtility {

    static func lockOrientation(_ orientation: UIInterfaceOrientationMask) {

        if let delegate = UIApplication.shared.delegate as? AppDelegate {
            delegate.orientationLock = orientation
        }
    }

    /// OPTIONAL Added method to adjust lock and rotate to the desired orientation
    static func lockOrientation(_ orientation: UIInterfaceOrientationMask, andRotateTo rotateOrientation:UIInterfaceOrientation) {

        self.lockOrientation(orientation)

        UIDevice.current.setValue(rotateOrientation.rawValue, forKey: "orientation")
        UINavigationController.attemptRotationToDeviceOrientation()
    }

}

AppUtility.lockOrientation(.portrait, andRotateTo: .portrait)

添加到BViewController:

override func viewDidLoad() {
        super.viewDidLoad()
   UIDevice.current.setValue(Int(UIInterfaceOrientation.landscapeLeft.rawValue), forKey: "orientation")
    }

    override func viewWillDisappear(_ animated: Bool) {
        UIDevice.current.setValue(Int(UIInterfaceOrientation.portrait.rawValue), forKey: "orientation")
    }