swift - 检测 iPad 的方向 - Swift Playgrounds

Question

我在 Swift Playgrounds 中运行以下代码，但每次更改 iPad 的方向时，代码都会打印“无法确定状态”。我做错了什么还是有其他方法？

import UIKit
import PlaygroundSupport

class MainViewController: UIViewController {
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        switch UIDevice.current.orientation {
        case .portrait:
            print("Portrait")
        case .landscapeLeft:
            print("Landscape Left")
        case .landscapeRight:
            print("Landscape Right")
        case .portraitUpsideDown:
            print("Portrait Upside Down")
        default:
            print("Unable to Determine State")
        }
    }

}

PlaygroundPage.current.liveView = MainViewController()

Answer 1

if UIDevice.currentDevice().orientation == UIDeviceOrientation.LandscapeLeft{

}
else if UIDevice.currentDevice().orientation == UIDeviceOrientation.LandscapeRight{

}
else if UIDevice.currentDevice().orientation == UIDeviceOrientation.UIDeviceOrientationPortraitUpsideDown{

}
else if UIDevice.currentDevice().orientation == UIDeviceOrientation.UIDeviceOrientationPortrait{

}

对于 Swift 4:

 override func didRotateFromInterfaceOrientation(fromInterfaceOrientation: UIInterfaceOrientation) {
    var text=""
    switch UIDevice.currentDevice().orientation{
    case .Portrait:
        text="Portrait"
    case .PortraitUpsideDown:
        text="PortraitUpsideDown"
    case .LandscapeLeft:
        text="LandscapeLeft"
    case .LandscapeRight:
        text="LandscapeRight"
    default:
        text="Another"
    }
    print("You have moved: \(text)")        
}