你提供给渐变的颜色必须是CGColor类型。设置CGColor数组为gl。colors。

正确的代码是:

class Colors {
    var gl:CAGradientLayer!

    init() {
        let colorTop = UIColor(red: 192.0 / 255.0, green: 38.0 / 255.0, blue: 42.0 / 255.0, alpha: 1.0).cgColor
        let colorBottom = UIColor(red: 35.0 / 255.0, green: 2.0 / 255.0, blue: 2.0 / 255.0, alpha: 1.0).cgColor

        self.gl = CAGradientLayer()
        self.gl.colors = [colorTop, colorBottom]
        self.gl.locations = [0.0, 1.0]
    }
}

如果你需要改变渐变的方向你必须使用startPoint和endPoint。

let gradient: CAGradientLayer = CAGradientLayer()

gradient.colors = [UIColor.blue.cgColor, UIColor.red.cgColor]
gradient.locations = [0.0 , 1.0]
gradient.startPoint = CGPoint(x: 0.0, y: 1.0)
gradient.endPoint = CGPoint(x: 1.0, y: 1.0)
gradient.frame = CGRect(x: 0.0, y: 0.0, width: self.view.frame.size.width, height: self.view.frame.size.height)

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

我做了一个UIView扩展应用一个基本的渐变到任何视图

extension UIView {
    func layerGradient() {
        let layer : CAGradientLayer = CAGradientLayer()
        layer.frame.size = self.frame.size
        layer.frame.origin = CGPointMake(0.0,0.0)
        layer.cornerRadius = CGFloat(frame.width / 20)

        let color0 = UIColor(red:250.0/255, green:250.0/255, blue:250.0/255, alpha:0.5).CGColor
        let color1 = UIColor(red:200.0/255, green:200.0/255, blue: 200.0/255, alpha:0.1).CGColor
        let color2 = UIColor(red:150.0/255, green:150.0/255, blue: 150.0/255, alpha:0.1).CGColor
        let color3 = UIColor(red:100.0/255, green:100.0/255, blue: 100.0/255, alpha:0.1).CGColor
        let color4 = UIColor(red:50.0/255, green:50.0/255, blue:50.0/255, alpha:0.1).CGColor
        let color5 = UIColor(red:0.0/255, green:0.0/255, blue:0.0/255, alpha:0.1).CGColor
        let color6 = UIColor(red:150.0/255, green:150.0/255, blue:150.0/255, alpha:0.1).CGColor

        layer.colors = [color0,color1,color2,color3,color4,color5,color6]
        self.layer.insertSublayer(layer, atIndex: 0)
    }
}       

如果你想使用HEX而不是RGBA，只需拖动一个新的空的.swift并添加下面提到的代码:

     import UIKit

    extension UIColor {
        convenience init(rgba: String) {
            var red:   CGFloat = 0.0
            var green: CGFloat = 0.0
            var blue:  CGFloat = 0.0
            var alpha: CGFloat = 1.0

            if rgba.hasPrefix("#") {
                let index   = advance(rgba.startIndex, 1)
                let hex     = rgba.substringFromIndex(index)
                let scanner = NSScanner(string: hex)
                var hexValue: CUnsignedLongLong = 0
                if scanner.scanHexLongLong(&hexValue) {
                    switch (count(hex)) {
                    case 3:
                        red   = CGFloat((hexValue & 0xF00) >> 8)       / 15.0
                        green = CGFloat((hexValue & 0x0F0) >> 4)       / 15.0
                        blue  = CGFloat(hexValue & 0x00F)              / 15.0
                    case 4:
                        red   = CGFloat((hexValue & 0xF000) >> 12)     / 15.0
                        green = CGFloat((hexValue & 0x0F00) >> 8)      / 15.0
                        blue  = CGFloat((hexValue & 0x00F0) >> 4)      / 15.0
                        alpha = CGFloat(hexValue & 0x000F)             / 15.0
                    case 6:
                        red   = CGFloat((hexValue & 0xFF0000) >> 16)   / 255.0
                        green = CGFloat((hexValue & 0x00FF00) >> 8)    / 255.0
                        blue  = CGFloat(hexValue & 0x0000FF)           / 255.0
                    case 8:
                        red   = CGFloat((hexValue & 0xFF000000) >> 24) / 255.0
                        green = CGFloat((hexValue & 0x00FF0000) >> 16) / 255.0
                        blue  = CGFloat((hexValue & 0x0000FF00) >> 8)  / 255.0
                        alpha = CGFloat(hexValue & 0x000000FF)         / 255.0
                    default:
                        print("Invalid RGB string, number of characters after '#' should be either 3, 4, 6 or 8")
                    }
                } else {
                    println("Scan hex error")
                }
            } else {
                print("Invalid RGB string, missing '#' as prefix")
            }
            self.init(red:red, green:green, blue:blue, alpha:alpha)
        }
}

类似地，拖动另一个空的.swift文件并添加下面提到的代码:

    class Colors {
    let colorTop = UIColor(rgba: "##8968CD").CGColor
    let colorBottom = UIColor(rgba: "#5D478B").CGColor

    let gl: CAGradientLayer

    init() {
        gl = CAGradientLayer()
        gl.colors = [ colorTop, colorBottom]
        gl.locations = [ 0.0, 1.0]
    }
}

然后在视图控制器中，在类下面实例化你的Color类，像这样:

let colors = Colors()

添加一个新函数:

func refresh() {
        view.backgroundColor = UIColor.clearColor()
        var backgroundLayer = colors.gl
        backgroundLayer.frame = view.frame
        view.layer.insertSublayer(backgroundLayer, atIndex: 0)
    }

在viewDidLoad中声明函数:

refresh()

你完成了:)) 如果与RGBA相比，使用HEX太容易了。: D

在Swift3试试这个:

 func addGradient(){

    let gradient:CAGradientLayer = CAGradientLayer()
    gradient.frame.size = self.viewThatHoldsGradient.frame.size
    gradient.colors = [UIColor.white.cgColor,UIColor.white.withAlphaComponent(0).cgColor] //Or any colors
    self.viewThatHoldsGradient.layer.addSublayer(gradient)

}

用这个自定义类扩展UIView。

GradientView.swift

import UIKit

class GradientView: UIView {

    // Default Colors
    var colors:[UIColor] = [UIColor.redColor(), UIColor.blueColor()]

    override func drawRect(rect: CGRect) {

        // Must be set when the rect is drawn
        setGradient(colors[0], color2: colors[1])
    }

    func setGradient(color1: UIColor, color2: UIColor) {

        let context = UIGraphicsGetCurrentContext()
        let gradient = CGGradientCreateWithColors(CGColorSpaceCreateDeviceRGB(), [color1.CGColor, color2.CGColor], [0, 1])!

        // Draw Path
        let path = UIBezierPath(rect: CGRectMake(0, 0, frame.width, frame.height))
        CGContextSaveGState(context)
        path.addClip()
        CGContextDrawLinearGradient(context, gradient, CGPointMake(frame.width / 2, 0), CGPointMake(frame.width / 2, frame.height), CGGradientDrawingOptions())
        CGContextRestoreGState(context)
    }

    override func layoutSubviews() {

        // Ensure view has a transparent background color (not required)
        backgroundColor = UIColor.clearColor()
    }

}

使用

gradientView。colors = [uiccolor . blackcolor ().colorWithAlphaComponent(0.8)， uiccolor . clearcolor ()]

结果

Xcode 11•Swift 5.1

你可以像下面这样设计你自己的渐变视图:

@IBDesignable
public class Gradient: UIView {
    @IBInspectable var startColor:   UIColor = .black { didSet { updateColors() }}
    @IBInspectable var endColor:     UIColor = .white { didSet { updateColors() }}
    @IBInspectable var startLocation: Double =   0.05 { didSet { updateLocations() }}
    @IBInspectable var endLocation:   Double =   0.95 { didSet { updateLocations() }}
    @IBInspectable var horizontalMode:  Bool =  false { didSet { updatePoints() }}
    @IBInspectable var diagonalMode:    Bool =  false { didSet { updatePoints() }}

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

    var gradientLayer: CAGradientLayer { layer as! CAGradientLayer }

    func updatePoints() {
        if horizontalMode {
            gradientLayer.startPoint = diagonalMode ? .init(x: 1, y: 0) : .init(x: 0, y: 0.5)
            gradientLayer.endPoint   = diagonalMode ? .init(x: 0, y: 1) : .init(x: 1, y: 0.5)
        } else {
            gradientLayer.startPoint = diagonalMode ? .init(x: 0, y: 0) : .init(x: 0.5, y: 0)
            gradientLayer.endPoint   = diagonalMode ? .init(x: 1, y: 1) : .init(x: 0.5, y: 1)
        }
    }
    func updateLocations() {
        gradientLayer.locations = [startLocation as NSNumber, endLocation as NSNumber]
    }
    func updateColors() {
        gradientLayer.colors = [startColor.cgColor, endColor.cgColor]
    }
    override public func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
        super.traitCollectionDidChange(previousTraitCollection)
        updatePoints()
        updateLocations()
        updateColors()
    }

}

清洁的代码，让你传递任何UIColor到GradientLayer类的实例:

class GradientLayer {

    let gradientLayer: CAGradientLayer
    let colorTop: CGColor
    let colorBottom: CGColor

    init(colorTop: UIColor, colorBottom: UIColor) {
        self.colorTop = colorTop.CGColor
        self.colorBottom = colorBottom.CGColor
        gradientLayer = CAGradientLayer()
        gradientLayer.colors = [colorTop, colorBottom]
        gradientLayer.locations = [0.0, 1.0]
    }
}

只是修改上面提到的答案。

func setGradientBackground() {
    let colorTop =  UIColor(red: 255.0/255.0, green: 149.0/255.0, blue: 0.0/255.0, alpha: 1.0).cgColor
    let colorBottom = UIColor(red: 255.0/255.0, green: 94.0/255.0, blue: 58.0/255.0, alpha: 1.0).cgColor
                
    let gradientLayer = CAGradientLayer()
    gradientLayer.colors = [colorTop, colorBottom]
    gradientLayer.locations = [0.0, 1.0]
    gradientLayer.frame = self.view.bounds
            
    self.view.layer.insertSublayer(gradientLayer, at:0)
}

然后在viewWillAppear中调用这个方法

override func viewWillAppear(_ animated: Bool) {
    setGradientBackground()
    super.viewWillAppear(animated)
}

这是一个快速扩展，你可以通过任意数量的颜色。在插入一个渐变图层之前，它会删除之前的任何渐变图层，如果需要的话，它会返回新插入的渐变图层进行进一步的操作:

    extension UIView {

    /**
     Given an Array of CGColor, it will:
        - Remove all sublayers of type CAGradientLayer.
        - Create and insert a new CAGradientLayer.

     - Parameters: 
        - colors: An Array of CGColor with the colors for the gradient fill

     - Returns: The newly created gradient CAGradientLayer
     */
    func layerGradient(colors c:[CGColor])->CAGradientLayer {
        self.layer.sublayers = self.layer.sublayers?.filter(){!($0 is CAGradientLayer)}
        let layer : CAGradientLayer = CAGradientLayer()
        layer.frame.size = self.frame.size
        layer.frame.origin = CGPointZero
        layer.colors = c
        self.layer.insertSublayer(layer, atIndex: 0)
        return layer
    }
}

Swift 3 -只使用纹理和SKSpriteNode，不需要UIView

import Foundation
import SpriteKit

class GradientSpriteNode : SKSpriteNode
{
    convenience init(size: CGSize, colors: [UIColor], locations: [CGFloat])
    {
        let texture = GradientSpriteNode.texture(size: size, colors: colors, locations: locations)
        self.init(texture: texture, color:SKColor.clear, size: texture.size())
    }

    private override init(texture: SKTexture!, color: SKColor, size: CGSize) {
        super.init(texture: texture, color: color, size: size)
    }

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

    private static func texture(size: CGSize, colors: [UIColor], locations: [CGFloat]) -> SKTexture
    {
        UIGraphicsBeginImageContext(size)
        let context = UIGraphicsGetCurrentContext()!
        let gradient = CGGradient(colorsSpace: CGColorSpaceCreateDeviceRGB(), colors: colors.map{$0.cgColor} as CFArray, locations: locations)!
        context.drawLinearGradient(gradient, start: CGPoint(x: size.width / 2, y: 0), end: CGPoint(x: size.width / 2, y: size.height), options: CGGradientDrawingOptions())
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return SKTexture(image: image!)

    }
}

用法:

let gradient = GradientSpriteNode(
        size: CGSize(width: 100, height: 100),
        colors: [UIColor.red, UIColor.blue],
        locations: [0.0, 1.0])
addChild(gradient)

这段代码将与Swift 3.0一起工作

class GradientView: UIView {

    override open class var layerClass: AnyClass {
        get{
            return CAGradientLayer.classForCoder()
        }
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        let gradientLayer = self.layer as! CAGradientLayer
        let color1 = UIColor.white.withAlphaComponent(0.1).cgColor as CGColor
        let color2 = UIColor.white.withAlphaComponent(0.9).cgColor as CGColor
        gradientLayer.locations = [0.60, 1.0]
        gradientLayer.colors = [color2, color1]
    }
}

只需要指定视图的框架，你想在其中显示渐变颜色。

let firstColor =  UIColor(red: 69/255, green: 90/255, blue: 195/255, alpha: 1.0).CGColor

 let secondColor = UIColor(red: 230/255, green: 44/255, blue: 75/255, alpha: 1.0).CGColor

    let gradientLayer = CAGradientLayer()
    gradientLayer.colors = [ firstColor, secondColor]
    gradientLayer.locations = [ 0.0, 1.0]
    gradientLayer.frame = CGRectMake(0, 0, 375, 64)// You can mention frame here

    self.view.layer.addSublayer(gradientLayer)

我有这些扩展:

@IBDesignable class GradientView: UIView {
    @IBInspectable var firstColor: UIColor = UIColor.red
    @IBInspectable var secondColor: UIColor = UIColor.green

    @IBInspectable var vertical: Bool = true

    lazy var gradientLayer: CAGradientLayer = {
        let layer = CAGradientLayer()
        layer.colors = [firstColor.cgColor, secondColor.cgColor]
        layer.startPoint = CGPoint.zero
        return layer
    }()

    //MARK: -

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        applyGradient()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        applyGradient()
    }

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        applyGradient()
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        updateGradientFrame()
    }

    //MARK: -

    func applyGradient() {
        updateGradientDirection()
        layer.sublayers = [gradientLayer]
    }

    func updateGradientFrame() {
        gradientLayer.frame = bounds
    }

    func updateGradientDirection() {
        gradientLayer.endPoint = vertical ? CGPoint(x: 0, y: 1) : CGPoint(x: 1, y: 0)
    }
}

@IBDesignable class ThreeColorsGradientView: UIView {
    @IBInspectable var firstColor: UIColor = UIColor.red
    @IBInspectable var secondColor: UIColor = UIColor.green
    @IBInspectable var thirdColor: UIColor = UIColor.blue

    @IBInspectable var vertical: Bool = true {
        didSet {
            updateGradientDirection()
        }
    }

    lazy var gradientLayer: CAGradientLayer = {
        let layer = CAGradientLayer()
        layer.colors = [firstColor.cgColor, secondColor.cgColor, thirdColor.cgColor]
        layer.startPoint = CGPoint.zero
        return layer
    }()

    //MARK: -

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        applyGradient()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        applyGradient()
    }

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        applyGradient()
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        updateGradientFrame()
    }

    //MARK: -

    func applyGradient() {
        updateGradientDirection()
        layer.sublayers = [gradientLayer]
    }

    func updateGradientFrame() {
        gradientLayer.frame = bounds
    }

    func updateGradientDirection() {
        gradientLayer.endPoint = vertical ? CGPoint(x: 0, y: 1) : CGPoint(x: 1, y: 0)
    }
}

@IBDesignable class RadialGradientView: UIView {

    @IBInspectable var outsideColor: UIColor = UIColor.red
    @IBInspectable var insideColor: UIColor = UIColor.green

    override func awakeFromNib() {
        super.awakeFromNib()

        applyGradient()
    }

    func applyGradient() {
        let colors = [insideColor.cgColor, outsideColor.cgColor] as CFArray
        let endRadius = sqrt(pow(frame.width/2, 2) + pow(frame.height/2, 2))
        let center = CGPoint(x: bounds.size.width / 2, y: bounds.size.height / 2)
        let gradient = CGGradient(colorsSpace: nil, colors: colors, locations: nil)
        let context = UIGraphicsGetCurrentContext()

        context?.drawRadialGradient(gradient!, startCenter: center, startRadius: 0.0, endCenter: center, endRadius: endRadius, options: CGGradientDrawingOptions.drawsBeforeStartLocation)
    }

    override func draw(_ rect: CGRect) {
        super.draw(rect)

        #if TARGET_INTERFACE_BUILDER
            applyGradient()
        #endif
    }
}

用法:

如果你有视图集合(多视图)，请这样做

  func setGradientBackground() {
    let v:UIView
    for v in viewgradian
    //here viewgradian is your view Collection Outlet name
    {
        let layer:CALayer
        var arr = [AnyObject]()
        for layer in v.layer.sublayers!
        {
           arr.append(layer)
        }

        let colorTop = UIColor(red: 216.0/255.0, green: 240.0/255.0, blue: 244.0/255.0, alpha: 1.0).cgColor
        let colorBottom = UIColor(red: 255.0/255.0, green: 255.0/255.0, blue: 255.0/255.0, alpha: 1.0).cgColor
        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [ colorBottom, colorTop]
        gradientLayer.startPoint = CGPoint(x: 1.0, y: 0.0)
        gradientLayer.endPoint = CGPoint(x: 0.0, y: 1.0)
        gradientLayer.frame = v.bounds
        v.layer.insertSublayer(gradientLayer, at: 0)
    }
}

下面是在可重用的Util类文件中进行设置的变体

在你的Xcode项目中:

Create a new Swift class call it UI_Util.swift, and populate it as follows: import Foundation import UIKit class UI_Util { static func setGradientGreenBlue(uiView: UIView) { let colorTop = UIColor(red: 15.0/255.0, green: 118.0/255.0, blue: 128.0/255.0, alpha: 1.0).cgColor let colorBottom = UIColor(red: 84.0/255.0, green: 187.0/255.0, blue: 187.0/255.0, alpha: 1.0).cgColor let gradientLayer = CAGradientLayer() gradientLayer.colors = [ colorTop, colorBottom] gradientLayer.locations = [ 0.0, 1.0] gradientLayer.frame = uiView.bounds uiView.layer.insertSublayer(gradientLayer, at: 0) } }

现在你可以像这样从任何ViewController调用这个函数: 类AbcViewController: UIViewController override func viewDidLoad() { super.viewDidLoad () UI_Util。setGradientGreen (uiView self。view): ｝

感谢katwal-Dipak对函数代码的回答

易于使用的扩展swift 3

extension CALayer {
    func addGradienBorder(colors:[UIColor] = [UIColor.red,UIColor.blue], width:CGFloat = 1) {
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame =  CGRect(origin: .zero, size: self.bounds.size)
        gradientLayer.startPoint = CGPoint(x:0.0, y:0.5)
        gradientLayer.endPoint = CGPoint(x:1.0, y:0.5)
        gradientLayer.colors = colors.map({$0.cgColor})

        let shapeLayer = CAShapeLayer()
        shapeLayer.lineWidth = width
        shapeLayer.path = UIBezierPath(rect: self.bounds).cgPath
        shapeLayer.fillColor = nil
        shapeLayer.strokeColor = UIColor.black.cgColor
        gradientLayer.mask = shapeLayer

        self.addSublayer(gradientLayer)
    }
}

用你的观点，例子

yourView.addGradienBorder(color: UIColor.black, opacity: 0.1, offset: CGSize(width:2 , height: 5), radius: 3, viewCornerRadius: 3.0)

试试这个，对我很有效，

  var gradientView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 35))
  let gradientLayer:CAGradientLayer = CAGradientLayer()
  gradientLayer.frame.size = self.gradientView.frame.size
  gradientLayer.colors = 
  [UIColor.white.cgColor,UIColor.red.withAlphaComponent(1).cgColor] 
  //Use diffrent colors
  gradientView.layer.addSublayer(gradientLayer)

你可以添加渐变颜色的起点和终点。

    gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
    gradientLayer.endPoint = CGPoint(x: 1.0, y: 1.0)

要了解更多详细描述，请参阅Best Answer或从Apple跟踪CAGradientLayer

希望这是对某人的帮助。

对于swift应用CAGradientLayer到任何对象(水平和垂直)

func makeGradientColor(`for` object : AnyObject , startPoint : CGPoint , endPoint : CGPoint) -> CAGradientLayer {
    let gradient: CAGradientLayer = CAGradientLayer()

    gradient.colors = [(UIColor(red: 59.0/255.0, green: 187.0/255.0, blue: 182.0/255.0, alpha: 1.00).cgColor), (UIColor(red: 57.0/255.0, green: 174.0/255.0, blue: 236.0/255.0, alpha: 1.00).cgColor)]
    gradient.locations = [0.0 , 1.0]

    gradient.startPoint = startPoint
    gradient.endPoint = endPoint
    gradient.frame = CGRect(x: 0.0, y: 0.0, width: object.frame.size.width, height: object.frame.size.height)
    return gradient
}

如何使用

let start : CGPoint = CGPoint(x: 0.0, y: 1.0)
let end : CGPoint = CGPoint(x: 1.0, y: 1.0)
let gradient: CAGradientLayer = self.makeGradientColor(for: vwTop, startPoint: start, endPoint: end)
vwTop.layer.insertSublayer(gradient, at: 0)

let start1 : CGPoint = CGPoint(x: 1.0, y: 1.0)
let end1 : CGPoint = CGPoint(x: 1.0, y: 0.0)
let gradient1: CAGradientLayer = self.makeGradientColor(for: vwTop, startPoint: start1, endPoint: end1)
vwBottom.layer.insertSublayer(gradient1, at: 0)

您可以在这里检查输出

我想添加一个渐变到一个视图，然后使用自动布局锚定它。

    class GradientView: UIView {

    private let gradient: CAGradientLayer = {
        let layer = CAGradientLayer()
        let topColor: UIColor = UIColor(red:0.98, green:0.96, blue:0.93, alpha:0.5)
        let bottomColor: UIColor = UIColor.white
        layer.colors = [topColor.cgColor, bottomColor.cgColor]
        layer.locations = [0,1]
        return layer
    }()

    init() {
        super.init(frame: .zero)
        gradient.frame = frame
        layer.insertSublayer(gradient, at: 0)
    }

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

    override func layoutSubviews() {
        super.layoutSubviews()
        gradient.frame = bounds

    }
}

斯威夫特4

添加一个视图出口

@IBOutlet弱变量梯度视图：UIView！

为视图添加渐变

func setGradient() {
    let gradient: CAGradientLayer = CAGradientLayer()
    gradient.colors = [UIColor.red.cgColor, UIColor.blue.cgColor]
    gradient.locations = [0.0 , 1.0]
    gradient.startPoint = CGPoint(x: 0.0, y: 1.0)
    gradient.endPoint = CGPoint(x: 1.0, y: 1.0)
    gradient.frame = gradientView.layer.frame
    gradientView.layer.insertSublayer(gradient, at: 0)
}

有一个名为Chameleon (https://github.com/viccalexander/Chameleon)的库可以用于渐变颜色。它甚至有渐变的风格来实现。这就是如何在swift 4 podfile中添加它 “变色龙框架/Swift”，:git => 'https://github.com/ViccAlexander/Chameleon.git'，:branch => 'wip/swift4'

import ChameleonFramework

let colors:[UIColor] = [
  UIColor.flatPurpleColorDark(), 
  UIColor.flatWhiteColor()
]
view.backgroundColor = GradientColor(.TopToBottom, frame: view.frame, colors: colors)

使用以下代码:

extension UIView {
func applyGradient(colours: [UIColor]) -> Void {
 let gradient: CAGradientLayer = CAGradientLayer()
 gradient.frame = self.bounds
 gradient.colors = colours.map { $0.cgColor }
 gradient.startPoint = CGPoint(x : 0.0, y : 0.5)
 gradient.endPoint = CGPoint(x :1.0, y: 0.5)
 self.layer.insertSublayer(gradient, at: 0)
 }
}

像这样调用这个函数:

  self.mainView.applyGradient(colours: [.green, .blue])

很容易

    // MARK: - Gradient
extension CAGradientLayer {
    enum Point {
        case topLeft
        case centerLeft
        case bottomLeft
        case topCenter
        case center
        case bottomCenter
        case topRight
        case centerRight
        case bottomRight
        var point: CGPoint {
            switch self {
            case .topLeft:
                return CGPoint(x: 0, y: 0)
            case .centerLeft:
                return CGPoint(x: 0, y: 0.5)
            case .bottomLeft:
                return CGPoint(x: 0, y: 1.0)
            case .topCenter:
                return CGPoint(x: 0.5, y: 0)
            case .center:
                return CGPoint(x: 0.5, y: 0.5)
            case .bottomCenter:
                return CGPoint(x: 0.5, y: 1.0)
            case .topRight:
                return CGPoint(x: 1.0, y: 0.0)
            case .centerRight:
                return CGPoint(x: 1.0, y: 0.5)
            case .bottomRight:
                return CGPoint(x: 1.0, y: 1.0)
            }
        }
    }
    convenience init(start: Point, end: Point, colors: [CGColor], type: CAGradientLayerType) {
        self.init()
        self.startPoint = start.point
        self.endPoint = end.point
        self.colors = colors
        self.locations = (0..<colors.count).map(NSNumber.init)
        self.type = type
    }
}

像这样使用:-

let fistColor = UIColor.white
let lastColor = UIColor.black
let gradient = CAGradientLayer(start: .topLeft, end: .topRight, colors: [fistColor.cgColor, lastColor.cgColor], type: .radial)
gradient.frame = yourView.bounds
yourView.layer.addSublayer(gradient)

添加渐变到图层，添加:

let layer = CAGradientLayer()
layer.frame = CGRect(x: 64, y: 64, width: 120, height: 120)
layer.colors = [UIColor.red.cgColor, UIColor.blue.cgColor]
view.layer.addSublayer(layer)

对于那些想要Objective C版本的答案的人。经过测试，在iOS13上运行

// Done here so that constraints have completed and the frame is correct.
- (void) viewDidLayoutSubviews { 
    [super viewDidLayoutSubviews];
    UIColor *colorTop = [UIColor colorWithRed:(CGFloat)192.0/255.0 green: 38.0/255.0 blue: 42.0/255.0 alpha:1.0];
    UIColor *colorBottom = [UIColor colorWithRed: 35.0/255.0 green: 2.0/255.0 blue: 2.0/255.0 alpha: 1.0];
    CAGradientLayer *gl = [CAGradientLayer new];
    [gl setColors:@[(id)[colorTop CGColor], (id)[colorBottom CGColor]]];
    [gl setLocations:@[@0.0f, @1.0f]];
    self.view.backgroundColor = [UIColor clearColor];
    CALayer *backgroundLayer = gl;
    backgroundLayer.frame = self.view.frame;
    [self.view.layer insertSublayer:backgroundLayer atIndex:0];
}

我注意到的一件事是，你不能在不清除文本的情况下给UILabel添加渐变。一个简单的解决方法是使用UIButton并禁用用户交互。

SwiftUI:你可以使用线性梯度结构作为ZStack的第一个元素。作为ZStack的“底部”，它将作为背景色。AngularGradient和RadialGradient也可用。

import SwiftUI

struct ContentView: View {
    var body: some View {
        ZStack {
            LinearGradient(gradient: Gradient(colors: [.red, .blue]), startPoint: .top, endPoint: .bottom)
                .edgesIgnoringSafeArea(.all)
            // Put other content here; it will appear on top of the background gradient
        }
    }
}

我把罗希特·西索迪亚和米高梅的答案混在了一起

// MARK: - Gradient

public enum CAGradientPoint {
    case topLeft
    case centerLeft
    case bottomLeft
    case topCenter
    case center
    case bottomCenter
    case topRight
    case centerRight
    case bottomRight
    var point: CGPoint {
        switch self {
        case .topLeft:
            return CGPoint(x: 0, y: 0)
        case .centerLeft:
            return CGPoint(x: 0, y: 0.5)
        case .bottomLeft:
            return CGPoint(x: 0, y: 1.0)
        case .topCenter:
            return CGPoint(x: 0.5, y: 0)
        case .center:
            return CGPoint(x: 0.5, y: 0.5)
        case .bottomCenter:
            return CGPoint(x: 0.5, y: 1.0)
        case .topRight:
            return CGPoint(x: 1.0, y: 0.0)
        case .centerRight:
            return CGPoint(x: 1.0, y: 0.5)
        case .bottomRight:
            return CGPoint(x: 1.0, y: 1.0)
        }
    }
}

extension CAGradientLayer {

    convenience init(start: CAGradientPoint, end: CAGradientPoint, colors: [CGColor], type: CAGradientLayerType) {
        self.init()
        self.frame.origin = CGPoint.zero
        self.startPoint = start.point
        self.endPoint = end.point
        self.colors = colors
        self.locations = (0..<colors.count).map(NSNumber.init)
        self.type = type
    }
}

extension UIView {

    func layerGradient(startPoint:CAGradientPoint, endPoint:CAGradientPoint ,colorArray:[CGColor], type:CAGradientLayerType ) {
        let gradient = CAGradientLayer(start: .topLeft, end: .topRight, colors: colorArray, type: type)
        gradient.frame.size = self.frame.size
        self.layer.insertSublayer(gradient, at: 0)
    }
}

To Use写:-

        btnUrdu.layer.cornerRadius = 25
        btnUrdu.layer.masksToBounds = true 
        btnUrdu.layerGradient(startPoint: .centerRight, endPoint: .centerLeft, colorArray: [UIColor.appBlue.cgColor, UIColor.appLightBlue.cgColor], type: .axial)

输出:

Xcode 11 | Swift 5

如果有人正在寻找一个快速和简单的方法来添加一个渐变视图:

extension UIView {
    
    func addGradient(colors: [UIColor] = [.blue, .white], locations: [NSNumber] = [0, 2], startPoint: CGPoint = CGPoint(x: 0.0, y: 1.0), endPoint: CGPoint = CGPoint(x: 1.0, y: 1.0), type: CAGradientLayerType = .axial){
        
        let gradient = CAGradientLayer()
        
        gradient.frame.size = self.frame.size
        gradient.frame.origin = CGPoint(x: 0.0, y: 0.0)

        // Iterates through the colors array and casts the individual elements to cgColor
        // Alternatively, one could use a CGColor Array in the first place or do this cast in a for-loop
        gradient.colors = colors.map{ $0.cgColor }
        
        gradient.locations = locations
        gradient.startPoint = startPoint
        gradient.endPoint = endPoint
        
        // Insert the new layer at the bottom-most position
        // This way we won't cover any other elements
        self.layer.insertSublayer(gradient, at: 0)
    }
}

关于如何使用扩展的例子:

// Testing
view.addGradient()
        
// Two Colors
view.addGradient(colors: [.init(rgb: 0x75BBDB), .black], locations: [0, 3])
        
// Full Blown
view.addGradient(colors: [.init(rgb: 0x75BBDB), .black], locations: [0, 3], startPoint: CGPoint(x: 0.0, y: 1.5), endPoint: CGPoint(x: 1.0, y: 2.0), type: .axial)

可选地，使用以下命令输入十六进制数字。init(rgb: 0x75BBDB)

extension UIColor {
   convenience init(red: Int, green: Int, blue: Int) {
       self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
   }

   convenience init(rgb: Int) {
       self.init(
           red: (rgb >> 16) & 0xFF,
           green: (rgb >> 8) & 0xFF,
           blue: rgb & 0xFF
       )
   }
}