UIView 框架在方向更改后不更新

Question

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。

编辑

我问这个问题是因为我需要像这个问题一样重绘关于方向变化的视图：Can't 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。

在viewDidLoad()我有

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)

Answer 1

上面接受的答案在转换之前返回帧大小。所以您的视图没有更新..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)

    }

Answer 2

要获取方向更改回调，您需要添加此通知

NotificationCenter.default.addObserver(self, selector: #selector(ViewController.rotated), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)

你需要实现这个方法

func rotated() {
    if(UIDeviceOrientationIsLandscape(UIDevice.current.orientation))
    {
        print("landscape")
    }

    if(UIDeviceOrientationIsPortrait(UIDevice.current.orientation))
    {
        print("Portrait")
    }
}

Answer 3

添加此功能，您将检测到方向变化：

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    if UIDevice.current.orientation.isLandscape {
        print("Landscape")
    } else if UIDevice.current.orientation.isPortrait {
        print("Portrait")
    }
}

Answer 4

这是我的解决方案，基于这些要求：

(1) 我的布局需要根据更大的尺寸、高度或宽度进行更改。 （基本上是人像或风景，但将来……？）

(2) 我的应用程序是通用的，所以我无法考虑尺寸等级或与之相关的任何覆盖。

(3) 我的应用也有照片编辑扩展，所以 UIApplication 不可用。 （此外，landscapeLeft 和 LandscapeRight 等方向不适用于此类扩展。）

注意：为了完整起见，我正在为 AutoLayout 添加我的结构。

UIViewController：

var p = [NSLayoutConstraint]()
var l = [NSLayoutConstraint]()
var initialOrientation = true
var isInPortrait = false

override func viewDidLoad() {
    super.viewDidLoad()
    // set up all constraints, including common, portrait and landscape
    setUpConstraints()  
}

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    if initialOrientation {
        initialOrientation = false
        if view.frame.width > view.frame.height {
            isInPortrait = false
        } else {
            isInPortrait = true
        }
        orientationChanged()
    } else {
        if view.orientationHasChanged(&isInPortrait) {
            orientationChanged()
        }
    }
}

func orientationChanged() {
    // this was split out because of other app-specific logic
    view.setOrientation(p, l)
}

UIView：

extension UIView {

    public func orientationHasChanged(_ isInPortrait:inout Bool) -> Bool {
        // always check against isInPortrait to reduce unnecessary AutoLayout changes!
        if self.frame.width > self.frame.height {
            if isInPortrait {
                isInPortrait = false
                return true
            }
        } else {
            if !isInPortrait {
                isInPortrait = true
                return true
            }
        }
        return false
    }
    public func setOrientation(_ p:[NSLayoutConstraint], _ l:[NSLayoutConstraint]) {
        NSLayoutConstraint.deactivate(l)
        NSLayoutConstraint.deactivate(p)
        if self.bounds.width > self.bounds.height {
            NSLayoutConstraint.activate(l)
        } else {
            NSLayoutConstraint.activate(p)
        }
    }
}

Answer 5

试试这个

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    if UIInterfaceOrientationIsLandscape(UIApplication.sharedApplication().statusBarOrientation) {

        print("Landscape mode called")

        if UI_USER_INTERFACE_IDIOM() == .Pad {
            print("Landscape mode in ipad");

        }
        else
        {
            print("Landscape mode in Iphone ")

        }
    } else {
        print("Portrait mode called")
        if UI_USER_INTERFACE_IDIOM() == .Pad {

            print("Portrait mode called in ipad")
        }
        else
        {
            print("Portrait mode called in iphone")
        }
    }
}
override func willRotateToInterfaceOrientation(toInterfaceOrientation:UIInterfaceOrientation, duration: NSTimeInterval) {
    print("willRotateToInterfaceOrientation method called");
    //Here you can invalidateLayout()
}

Answer 6

override func willRotate(to toInterfaceOrientation: UIInterfaceOrientation, duration: TimeInterval) {

    self.sliding.setNeedsDisplay()

}

Answer 7

如果您使用它来获取 traitCollection 的更新值，请改用它

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    print("Trait collection changes")

}