3

我有一个 UIViewController，我在其中将 CALayer 子类添加到视图层：

[self.view.layer addSublayer:myObject.backgroundLayer];

当我旋转设备时，视图会旋转，但 CALayer 不会。它有点被分流到左边，仍然是纵向视图。

有没有办法让子层自动旋转或者我需要应用变换？

4

2 回答 2

4

使用 Swift 4 / iOS 11，根据您的需要，您可以选择以下 6 个示例之一，以便在设备旋转时管理您的CALayer/框架。CAGradientLayer

下面的示例使用CAGradientLayer但可以很容易地映射到CALayer或CAShapeLayer案例。

#1。覆盖UIViewController viewDidLayoutSubviews()

import UIKit

class ViewController: UIViewController {

    let gradientLayer: CAGradientLayer = {
        let layer = CAGradientLayer()
        layer.colors = [
            UIColor.blue.cgColor,
            UIColor.cyan.cgColor
        ]
        return layer
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        view.layer.addSublayer(gradientLayer)
        gradientLayer.frame = view.bounds
    }

    override func viewDidLayoutSubviews() {         
        gradientLayer.frame = view.bounds
    }

}

#2。覆盖UIViewController loadView(),子类化UIView和覆盖UIView layoutSubviews()

层视图.swift

import UIKit

class LayerView: UIView {

    lazy var gradientLayer: CAGradientLayer = {
        let layer = CAGradientLayer()
        layer.colors = [
            UIColor.blue.cgColor,
            UIColor.cyan.cgColor
        ]
        self.layer.addSublayer(layer)
        return layer
    }()

    override func layoutSubviews() {
        gradientLayer.frame = bounds
    }

}

LayerView.swift （替代）

import UIKit

class LayerView: UIView {

    var gradientLayer: CAGradientLayer!

    override func layoutSubviews() {
        if gradientLayer == nil {
            let gradientLayer = CAGradientLayer()
            gradientLayer.colors = [
                UIColor.blue.cgColor,
                UIColor.cyan.cgColor
            ]
            self.gradientLayer = gradientLayer
            layer.addSublayer(gradientLayer)
        }

        gradientLayer.frame = bounds
    }

}

ViewController.swift

import UIKit

class ViewController: UIViewController {

    let layerView = LayerView()

    override func loadView() {
        view = layerView
    }

}

#3。使用键值观察 (KVO)

import UIKit

class ViewController: UIViewController {

    var observation: NSKeyValueObservation?

    let gradientLayer: CAGradientLayer = {
        let layer = CAGradientLayer()
        layer.colors = [
            UIColor.blue.cgColor,
            UIColor.cyan.cgColor
        ]
        return layer
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        view.layer.addSublayer(gradientLayer)

        observation = view.observe(\.frame, options: [.new], changeHandler: { [unowned self] (object: UIView, change: NSKeyValueObservedChange<CGRect>) in
            guard let frame = change.newValue else { return }
            self.gradientLayer.frame = frame
        })

        // Also works
        /*
        observation = observe(\.view.frame, options: [.new], changeHandler: { [unowned self] (object: ViewController, change: NSKeyValueObservedChange<CGRect>) in
            guard let frame = change.newValue else { return }
            self.gradientLayer.frame = frame
        })
        */
    }

}

#4。覆盖UIViewController loadView(),子类化UIView和覆盖UIView layerClass

层视图.swift

import UIKit

class LayerView: UIView {

    override public class var layerClass: AnyClass {
        return CAGradientLayer.self
    }

    required init() {
        super.init(frame: .zero)

        guard let gradientLayer = layer as? CAGradientLayer else { return }
        gradientLayer.colors = [
            UIColor.blue.cgColor,
            UIColor.cyan.cgColor
        ]
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

ViewController.swift

import UIKit

class ViewController: UIViewController {

    let layerView = LayerView()

    override func loadView() {
        view = layerView
    }

}

#5。覆盖UIViewController loadView(),子类化UIView和覆盖CALayerDelegate layoutSublayers(of:)

层视图.swift

import UIKit

class LayerView: UIView {

    required init() {
        super.init(frame: .zero)

        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [
            UIColor.blue.cgColor,
            UIColor.cyan.cgColor
        ]

        layer.addSublayer(gradientLayer)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func layoutSublayers(of layer: CALayer) {
        layer.sublayers?.forEach {
            $0.frame = layer.bounds
        }
    }

}

ViewController.swift

import UIKit

class ViewController: UIViewController {

    let layerView = LayerView()

    override func loadView() {
        view = layerView
    }

}

#6。覆盖UIViewController loadView()、子类化UIView、覆盖UIView layerClass、子类化CALayer和覆盖CALayer layoutSublayers()

层.swift

import UIKit

class Layer: CALayer {

    override init() {
        super.init()

        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [
            UIColor.blue.cgColor,
            UIColor.cyan.cgColor
        ]

        addSublayer(gradientLayer)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func layoutSublayers() {
        sublayers?.forEach {
            $0.frame = bounds
        }
    }

}

层视图.swift

import UIKit

class LayerView: UIView {

    override public class var layerClass: AnyClass {
        return Layer.self
    }

}

ViewController.swift

import UIKit

class ViewController: UIViewController {

    let layerView = LayerView()

    override func loadView() {
        view = layerView
    }

}

资料来源：

于 2017-06-27T21:46:26.213 回答
0

您需要自己管理 CALayer 的旋转。我相信 0,0 保持在同一个位置，并且大小会更改以匹配新的方向，所以如果你想自己做一些事情，你需要自己管理旋转变换的添加。

于 2009-08-15T16:54:35.807 回答