斯威夫特4:

正确显示IB中的梯度:

@IBDesignable public class GradientView: UIView {

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

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

    public override init(frame: CGRect) {
        super.init(frame: frame)
        configureGradientLayer()
    }

    func configureGradientLayer() {
        let gradientLayer = layer as! CAGradientLayer
        gradientLayer.colors = [UIColor(hex: 0x003399).cgColor, UIColor(hex: 0x00297b).cgColor]
    }
}

调用上面的解决方案来更新层是一个好主意

viewDidLayoutSubviews 

正确地更新视图

斯威夫特3

在视图上添加一个渐变层

Bind your view outlet @IBOutlet var YOURVIEW : UIView! Define the CAGradientLayer() var gradient = CAGradientLayer() Here is the code you have to write in your viewDidLoad YOURVIEW.layoutIfNeeded() gradient.startPoint = CGPoint(x: CGFloat(0), y: CGFloat(1)) gradient.endPoint = CGPoint(x: CGFloat(1), y: CGFloat(0)) gradient.frame = YOURVIEW.bounds gradient.colors = [UIColor.red.cgColor, UIColor.green.cgColor] gradient.colors = [ UIColor(red: 255.0/255.0, green: 56.0/255.0, blue: 224.0/255.0, alpha: 1.0).cgColor,UIColor(red: 86.0/255.0, green: 13.0/255.0, blue: 232.0/255.0, alpha: 1.0).cgColor,UIColor(red: 16.0/255.0, green: 173.0/255.0, blue: 245.0/255.0, alpha: 1.0).cgColor] gradient.locations = [0.0 ,0.6 ,1.0] YOURVIEW.layer.insertSublayer(gradient, at: 0)

objective - c:

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 50)];
CAGradientLayer *gradient = [CAGradientLayer layer];

gradient.frame = view.bounds;
gradient.colors = @[(id)[UIColor whiteColor].CGColor, (id)[UIColor blackColor].CGColor];

[view.layer insertSublayer:gradient atIndex:0];

迅速:

let view = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 50))
let gradient = CAGradientLayer()

gradient.frame = view.bounds
gradient.colors = [UIColor.white.cgColor, UIColor.black.cgColor]

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

信息:使用startPoint和endPoint改变梯度的方向。

如果有任何其他视图添加到这个UIView(比如一个UILabel)，你可能想要考虑设置那些UIView的背景色为[UIColor clearColor]，这样渐变视图就会呈现而不是子视图的背景色。使用clearColor会对性能造成轻微的影响。

我已经使用Swift的扩展功能和枚举扩展了接受的答案。

哦，如果你像我一样使用Storyboard，一定要在viewDidLayoutSubviews()或以后调用gradientBackground(from:to:direction:)。

斯威夫特3

enum GradientDirection {
    case leftToRight
    case rightToLeft
    case topToBottom
    case bottomToTop
}

extension UIView {
    func gradientBackground(from color1: UIColor, to color2: UIColor, direction: GradientDirection) {
        let gradient = CAGradientLayer()
        gradient.frame = self.bounds
        gradient.colors = [color1.cgColor, color2.cgColor]

        switch direction {
        case .leftToRight:
            gradient.startPoint = CGPoint(x: 0.0, y: 0.5)
            gradient.endPoint = CGPoint(x: 1.0, y: 0.5)
        case .rightToLeft:
            gradient.startPoint = CGPoint(x: 1.0, y: 0.5)
            gradient.endPoint = CGPoint(x: 0.0, y: 0.5)
        case .bottomToTop:
            gradient.startPoint = CGPoint(x: 0.5, y: 1.0)
            gradient.endPoint = CGPoint(x: 0.5, y: 0.0)
        default:
            break
        }

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

试试这个对我来说很有魔力，

Objective - C

我已经设置了RGB渐变背景颜色为UIview

   UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0,0,320,35)];
   CAGradientLayer *gradient = [CAGradientLayer layer];
   gradient.frame = view.bounds;
   gradient.startPoint = CGPointZero;
   gradient.endPoint = CGPointMake(1, 1);
   gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor colorWithRed:34.0/255.0 green:211/255.0 blue:198/255.0 alpha:1.0] CGColor],(id)[[UIColor colorWithRed:145/255.0 green:72.0/255.0 blue:203/255.0 alpha:1.0] CGColor], nil];
   [view.layer addSublayer:gradient];

更新: Swift3 +

代码:

 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)

更多细节请参考CAGradientLayer文档

希望这对一些人有所帮助。