如何应用梯度的背景视图的iOS Swift应用程序

我试图应用渐变作为一个视图(故事板的主视图)的背景色。代码运行，但没有任何变化。我使用xCode Beta 2和Swift。

代码如下:

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

  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:

  let colors = Colors()

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

当前回答

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)

2019-07-16 06:27:41

其他回答

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)

}

2015-11-29 10:27:18

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]
    }
}

2014-06-24 07:39:05

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)

2015-01-17 21:39:00

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)
    }
}

2015-01-27 04:04:12

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)

2016-12-13 07:58:02

如何应用梯度的背景视图的iOS Swift应用程序

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