在Swift 4中不推荐使用init(colorLiteralRed:,green:,blue:,alpha :)

Question

let startingColorOfGradient = UIColor(colorLiteralRed: 255/255, green: 
255/255, blue: 255/255, alpha: 1.0).cgColor
let endingColorOFGradient = UIColor(colorLiteralRed: 251/255, green: 
247/255, blue: 234/255, alpha: 1.0).cgColor
let gradient: CAGradientLayer = CAGradientLayer()

错误:

'init(colorLiteralRed:green:blue:alpha :)'在Swift 4.0中被淘汰(Swift._ExpressibleByColorLiteral)

如果init(colorLiteralRed:,green:,blue:,alpha:)在Swift 4中弃用,如何使用渐变颜色？

Answer 1

init(colorLiteralRed:green:blue:alpha:) 旨在与由开发工具管理的Color Literals一起使用.

你为什么不使用正常的init(red:green:blue:alpha:)？

let startingColorOfGradient = UIColor(red: 255.0/255.0, green:
    255.0/255.0, blue: 255.0/255.0, alpha: 1.0).cgColor
let endingColorOFGradient = UIColor(red: 251.0/255.0, green:
    247.0/255.0, blue: 234.0/255.0, alpha: 1.0).cgColor
let gradient: CAGradientLayer = CAGradientLayer()

(234.0/255.0在上面的Swift中,上下文中的写法不是强制性的.但它阻止Swift编译器234/255在其他一些上下文中解释为整数除法.)