1. 先增加屏幕监听通知

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        // 检测设备方向
         NotificationCenter.default.addObserver(self, selector: #selector(receivedRotation), name: .UIDeviceOrientationDidChange, object: nil)
    }

2. 通知函数

    //通知监听触发的方法
    func receivedRotation(){
        // 屏幕方向
        switch UIDevice.current.orientation {
        case UIDeviceOrientation.unknown:
            print("方向未知")
        case .portrait: // Device oriented vertically, home button on the bottom
            print("屏幕直立")
        case .portraitUpsideDown: // Device oriented vertically, home button on the top
            print("屏幕倒立")
        case .landscapeLeft: // Device oriented horizontally, home button on the right
            print("屏幕左在上方")
        case .landscapeRight: // Device oriented horizontally, home button on the left
            print("屏幕右在上方")
        case .faceUp: // Device oriented flat, face up
            print("屏幕朝上")
        case .faceDown: // Device oriented flat, face down
            print("屏幕朝下")
        }
    }