我试图在Swift中使用十六进制颜色值,而不是UIColor允许您使用的少数标准值,但我不知道如何做到这一点。
示例:我如何使用#ffffff作为颜色?
我试图在Swift中使用十六进制颜色值,而不是UIColor允许您使用的少数标准值,但我不知道如何做到这一点。
示例:我如何使用#ffffff作为颜色?
当前回答
extension UIColor {
convenience init(r: CGFloat, g: CGFloat, b: CGFloat, a: CGFloat = 1) {
self.init(red: r/255, green: g/255, blue: b/255, alpha: a)
}
convenience init(hex: Int, alpha: CGFloat = 1) {
self.init(r: CGFloat((hex >> 16) & 0xff), g: CGFloat((hex >> 08) & 0xff), b: CGFloat((hex >> 00) & 0xff), a: alpha)
}
}
其他回答
Swift 5:你可以在Xcode中创建颜色,如下图所示:
您应该命名颜色,因为您通过名称引用了颜色。如图2所示:
这是UIColor的一个Swift扩展,它采用十六进制字符串:
import UIKit
extension UIColor {
convenience init(hexString: String) {
// Trim leading '#' if needed
var cleanedHexString = hexString
if hexString.hasPrefix("#") {
// cleanedHexString = dropFirst(hexString) // Swift 1.2
cleanedHexString = String(hexString.characters.dropFirst()) // Swift 2
}
// String -> UInt32
var rgbValue: UInt32 = 0
NSScanner(string: cleanedHexString).scanHexInt(&rgbValue)
// UInt32 -> R,G,B
let red = CGFloat((rgbValue >> 16) & 0xff) / 255.0
let green = CGFloat((rgbValue >> 08) & 0xff) / 255.0
let blue = CGFloat((rgbValue >> 00) & 0xff) / 255.0
self.init(red: red, green: green, blue: blue, alpha: 1.0)
}
}
Swift 4:结合Sulthan和Luca Torella的回答:
extension UIColor {
convenience init(hexFromString:String, alpha:CGFloat = 1.0) {
var cString:String = hexFromString.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
var rgbValue:UInt32 = 10066329 //color #999999 if string has wrong format
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.count) == 6) {
Scanner(string: cString).scanHexInt32(&rgbValue)
}
self.init(
red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: alpha
)
}
}
使用例子:
let myColor = UIColor(hexFromString: "4F9BF5")
let myColor = UIColor(hexFromString: "#4F9BF5")
let myColor = UIColor(hexFromString: "#4F9BF5", alpha: 0.5)
extension UIColor {
convenience init(hex: Int, alpha: Double = 1.0) {
self.init(red: CGFloat((hex>>16)&0xFF)/255.0, green:CGFloat((hex>>8)&0xFF)/255.0, blue: CGFloat((hex)&0xFF)/255.0, alpha: CGFloat(255 * alpha) / 255)
}
}
使用这个扩展像:
let selectedColor = UIColor(hex: 0xFFFFFF)
let selectedColor = UIColor(hex: 0xFFFFFF, alpha: 0.5)
我做了一个小函数,把它放在我可以全局使用它的地方,在swift 2.1中工作得很好:
func getColorFromHex(rgbValue:UInt32)->UIColor{
let red = CGFloat((rgbValue & 0xFF0000) >> 16)/255.0
let green = CGFloat((rgbValue & 0xFF00) >> 8)/255.0
let blue = CGFloat(rgbValue & 0xFF)/255.0
return UIColor(red:red, green:green, blue:blue, alpha:1.0)
}
用法:
getColorFromHex(0xffffff)