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];
}

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
       )
   }
}

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

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)

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。