ios - 渐变色作为 Swift4 中 UIButton 的背景色

Question

我有一个按钮，我正在尝试设置它的背景颜色渐变。我有三个十六进制值，我将它们转换为 RGB 并在我的代码中写入三个值，并将所有三个值传递给按钮框架。但是当我运行应用程序按钮时，背景不会根据我在代码中设置的颜色而改变。我得到三种颜色代码的代码是这样的，

 let gradientColor = CAGradientLayer()
    gradientColor.frame = loginButton.frame
    let color1 = UIColor(red: 183, green: 46, blue: 79, alpha: 1)
    let color2 = UIColor(red: 232, green: 79, blue: 80, alpha: 1)
    let color3 = UIColor(red: 145, green: 21, blue: 79, alpha: 1)
    gradientColor.colors = [color1,color2,color3]
    self.loginButton.layer.addSublayer(gradientColor)

Answer 1

试试看:

@IBOutlet weak var loginButton: UIButton!
func testGradientButton() -> Void {
    let gradientColor = CAGradientLayer()
    gradientColor.frame = loginButton.frame
    gradientColor.colors = [UIColor.blue.cgColor,UIColor.red.withAlphaComponent(1).cgColor]
    self.loginButton.layer.insertSublayer(gradientColor, at: 0)
}

结果如下:

另请注意:代码中 RGB 颜色的值远高于其正常值。查看您的控制台日志，它可能打印出以下错误:

[Graphics] UIColor created with component values far outside the expected range. Set a breakpoint on UIColorBreakForOutOfRangeColorComponents to debug. This message will only be logged once.

将所有值除以 255.0 并使用 insertSubLayer 函数。

let color1 = UIColor(red: 183.0/255.0, green: 46.0/255.0, blue: 79.0/255.0, alpha: 1)
let color2 = UIColor(red: 232.0/255.0, green: 79.0/255.0, blue: 80.0/255.0, alpha: 1)
let color3 = UIColor(red: 145.0/255.0, green: 21.0/255.0, blue: 79.0/255.0, alpha: 1)

这是您的颜色代码值的结果:

func testGradientButton() -> Void {
    let gradientColor = CAGradientLayer()
    gradientColor.frame = loginButton.frame
    let color1 = UIColor(red: 183.0/255.0, green: 46.0/255.0, blue: 79.0/255.0, alpha: 1)
    let color2 = UIColor(red: 232.0/255.0, green: 79.0/255.0, blue: 80.0/255.0, alpha: 1)
    let color3 = UIColor(red: 145.0/255.0, green: 21.0/255.0, blue: 79.0/255.0, alpha: 1)
    gradientColor.colors = [color1.cgColor,color2.cgColor,color3.cgColor]
    self.loginButton.layer.insertSublayer(gradientColor, at: 0)
}