方向更改后 UIView 框架不更新

如何使用 Swift 3 检测方向变化？

我需要在更改后检测它以计算帧大小。

EDIT

我问这个问题是因为我需要重新绘制方向变化的视图，就像这个问题一样：旋转时无法让背景渐变填充整个屏幕 https://stackoverflow.com/questions/20925939/cant-get-background-gradient-to-fill-entire-screen-upon-rotation

我不知道如何实现标记为正确答案的答案。

我尝试了另一个答案

self.backgroundImageView.layer.sublayers?.first?.frame = self.view.bounds

但它不起作用。

In viewDidLoad() I have

let color1 =  UIColor(red: 225.0/255.0, green: 210.0/255.0, blue: 0.0/255.0, alpha: 1.0).cgColor
let color2 = UIColor(red: 255.0/255.0, green: 125.0/255.0, blue: 77.0/255.0, alpha: 1.0).cgColor

let gradientLayer = CAGradientLayer()
gradientLayer.colors = [color1, color2]
gradientLayer.locations = [ 0.0, 1.0]
gradientLayer.frame = self.view.bounds

self.view.layer.insertSublayer(gradientLayer, at: 0)

上面接受的答案返回转换前的帧大小。因此您的视图没有更新。您需要在转换完成后获取帧大小。

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

        coordinator.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) -> Void in

            let orient = UIApplication.shared.statusBarOrientation

            switch orient {

            case .portrait:

                print("Portrait")

            case .landscapeLeft,.landscapeRight :

                print("Landscape")

            default:

                print("Anything But Portrait")
            }

            }, completion: { (UIViewControllerTransitionCoordinatorContext) -> Void in
                //refresh view once rotation is completed not in will transition as it returns incorrect frame size.Refresh here           

        })
        super.viewWillTransition(to: size, with: coordinator)

    }