我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
斯威夫特版本:
extension UIColor {
convenience init?(var hex: String) {
hex = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
hex = (hex.hasPrefix("#")) ? hex.substringFromIndex(advance(hex.startIndex, 1)) : hex
var value: UInt32 = 0
if NSScanner(string: hex).scanHexInt(&value) {
if count(hex) == 8 {
self.init(red: CGFloat((value & 0xFF000000) >> 24) / 255.0,
green: CGFloat((value & 0x00FF0000) >> 16) / 255.0,
blue: CGFloat((value & 0x0000FF00) >> 8) / 255.0,
alpha: CGFloat((value & 0x000000FF)) / 255.0)
return
} else if count(hex) == 6 {
self.init(red: CGFloat((value & 0xFF0000) >> 16) / 255.0,
green: CGFloat((value & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(value & 0x0000FF) / 255.0,
alpha: 1.0)
return
}
}
self.init()
return nil
}
}
其他回答
Swift 5, iOS 14
convenience init(hex: String, alpha: CGFloat = 1.0) {
var hexFormatted: String = hex.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).uppercased()
if hexFormatted.hasPrefix("#") {
hexFormatted = String(hexFormatted.dropFirst())
}
assert(hexFormatted.count == 6, "Invalid hex code used.")
var rgbValue: UInt64 = 0
Scanner(string: hexFormatted).scanHexInt64(&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)
}
我发现最简单的方法是使用宏。只要把它包括在你的标题中,它就可以在你的整个项目中使用。
#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]
Uicolor宏十六进制值
这段代码的格式化版本:
#define UIColorFromRGB(rgbValue) \
[UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 \
green:((float)((rgbValue & 0x00FF00) >> 8))/255.0 \
blue:((float)((rgbValue & 0x0000FF) >> 0))/255.0 \
alpha:1.0]
用法:
label.textColor = UIColorFromRGB(0xBC1128);
迅速:
static func UIColorFromRGB(_ rgbValue: Int) -> UIColor! {
return UIColor(
red: CGFloat((Float((rgbValue & 0xff0000) >> 16)) / 255.0),
green: CGFloat((Float((rgbValue & 0x00ff00) >> 8)) / 255.0),
blue: CGFloat((Float((rgbValue & 0x0000ff) >> 0)) / 255.0),
alpha: 1.0)
}
十六进制初始化
extension UIColor{
public convenience init(hex : String) {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.count) != 6) {
self.init(red: 1, green: 1, blue: 1, alpha: 1)
return
}
var rgbValue:UInt32 = 0
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: CGFloat(1.0)
)
}
//Iniitailization
let myColor = UIColor(hex: "#452b4e")
编码愉快!享受! !
使用任何转换器网站将十六进制颜色转换为RGB值(如果你谷歌“十六进制到RGB”,你会看到一吨)。例如,这个:http://www.rgbtohex.net/hextorgb/
然后将颜色属性更改为UIColor。例子:
self.profilePicture.layer.borderColor = [UIColor colorWithRed:0 green:167 blue:142 alpha:1.0].CGColor;
十六进制颜色值是:00a78e转换为RGB: R: 0 G: 167 B: 142
如果你给出的RGB值不在0到1.0之间,你必须将它们除以255。例子:
self.profilePicture.layer.borderColor = [UIColor colorWithRed:83.00/255.0 green:123.00/255.0 blue:53.00/255.0 alpha:1.0].CGColor;
extension UIColor {
convenience init(hexaString: String, alpha: CGFloat = 1) {
let chars = Array(hexaString.dropFirst())
self.init(red: .init(strtoul(String(chars[0...1]),nil,16))/255,
green: .init(strtoul(String(chars[2...3]),nil,16))/255,
blue: .init(strtoul(String(chars[4...5]),nil,16))/255,
alpha: alpha)}
}
用法:
let redColor = UIColor(hexaString: "#FF0000") // r 1,0 g 0,0 b 0,0 a 1,0
let transparentRed = UIColor(hexaString: "#FF0000", alpha: 0.5) // r 1,0 g 0,0 b 0,0 a 0,5
另一种选择是将六值转换为无符号整数,并从中提取相应的值:
extension UIColor {
convenience init(hexaString: String, alpha: CGFloat = 1) {
self.init(hexa: UInt(hexaString.dropFirst(), radix: 16) ?? 0, alpha: alpha)
}
convenience init(hexa: UInt, alpha: CGFloat = 1) {
self.init(red: .init((hexa & 0xff0000) >> 16) / 255,
green: .init((hexa & 0xff00 ) >> 8) / 255,
blue: .init( hexa & 0xff ) / 255,
alpha: alpha)
}
}
let purpleColor = UIColor(hexaString: "#FF00FF") // r 1,0 g 0,0 b 1,0 a 1,0
let transparentYellow = UIColor(hexaString: "#FFFF00", alpha: 0.5) // r 1,0 g 1,0 b 0,0 a 0,5
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