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
这个答案展示了如何在Obj-C中实现。这座桥是要用的
let rgbValue = 0xFFEEDD
let r = Float((rgbValue & 0xFF0000) >> 16)/255.0
let g = Float((rgbValue & 0xFF00) >> 8)/255.0
let b = Float((rgbValue & 0xFF))/255.0
self.backgroundColor = UIColor(red:r, green: g, blue: b, alpha: 1.0)
其他回答
这是一个接受十六进制字符串并返回UIColor的函数。 (你可以输入十六进制字符串格式:#ffffff或ffffff)
用法:
var color1 = hexStringToUIColor("#d3d3d3")
Swift 5:(Swift 4+)
func hexStringToUIColor (hex:String) -> UIColor {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.count) != 6) {
return UIColor.gray
}
var rgbValue:UInt64 = 0
Scanner(string: cString).scanHexInt64(&rgbValue)
return UIColor(
red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: CGFloat(1.0)
)
}
斯威夫特3:
func hexStringToUIColor (hex:String) -> UIColor {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.characters.count) != 6) {
return UIColor.gray
}
var rgbValue:UInt32 = 0
Scanner(string: cString).scanHexInt32(&rgbValue)
return UIColor(
red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: CGFloat(1.0)
)
}
斯威夫特2:
func hexStringToUIColor (hex:String) -> UIColor {
var cString:String = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet() as NSCharacterSet).uppercaseString
if (cString.hasPrefix("#")) {
cString = cString.substringFromIndex(cString.startIndex.advancedBy(1))
}
if ((cString.characters.count) != 6) {
return UIColor.grayColor()
}
var rgbValue:UInt32 = 0
NSScanner(string: cString).scanHexInt(&rgbValue)
return UIColor(
red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: CGFloat(1.0)
)
}
沙德源代码:/ gist: de147c42d7b3063ef7bc
编辑:更新代码。谢谢,Hlung, jaytrixz, Ahmad F, Kegham K和Adam Waite!
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)
你可以在UIColor上使用这个扩展,它将你的字符串(十六进制,RGBA)转换为UIColor,反之亦然。
extension UIColor {
//Convert RGBA String to UIColor object
//"rgbaString" must be separated by space "0.5 0.6 0.7 1.0" 50% of Red 60% of Green 70% of Blue Alpha 100%
public convenience init?(rgbaString : String){
self.init(ciColor: CIColor(string: rgbaString))
}
//Convert UIColor to RGBA String
func toRGBAString()-> String {
var r: CGFloat = 0
var g: CGFloat = 0
var b: CGFloat = 0
var a: CGFloat = 0
self.getRed(&r, green: &g, blue: &b, alpha: &a)
return "\(r) \(g) \(b) \(a)"
}
//return UIColor from Hexadecimal Color string
public convenience init?(hexString: String) {
let r, g, b, a: CGFloat
if hexString.hasPrefix("#") {
let start = hexString.index(hexString.startIndex, offsetBy: 1)
let hexColor = hexString.substring(from: start)
if hexColor.characters.count == 8 {
let scanner = Scanner(string: hexColor)
var hexNumber: UInt64 = 0
if scanner.scanHexInt64(&hexNumber) {
r = CGFloat((hexNumber & 0xff000000) >> 24) / 255
g = CGFloat((hexNumber & 0x00ff0000) >> 16) / 255
b = CGFloat((hexNumber & 0x0000ff00) >> 8) / 255
a = CGFloat(hexNumber & 0x000000ff) / 255
self.init(red: r, green: g, blue: b, alpha: a)
return
}
}
}
return nil
}
// Convert UIColor to Hexadecimal String
func toHexString() -> String {
var r: CGFloat = 0
var g: CGFloat = 0
var b: CGFloat = 0
var a: CGFloat = 0
self.getRed(&r, green: &g, blue: &b, alpha: &a)
return String(
format: "%02X%02X%02X",
Int(r * 0xff),
Int(g * 0xff),
Int(b * 0xff))
}
}
斯威夫特2.3: 用户界面颜色扩展。我认为这样更简单。
extension UIColor {
static func colorFromHex(hexString: String, alpha: CGFloat = 1) -> UIColor {
//checking if hex has 7 characters or not including '#'
if hexString.characters.count < 7 {
return UIColor.whiteColor()
}
//string by removing hash
let hexStringWithoutHash = hexString.substringFromIndex(hexString.startIndex.advancedBy(1))
//I am extracting three parts of hex color Red (first 2 characters), Green (middle 2 characters), Blue (last two characters)
let eachColor = [
hexStringWithoutHash.substringWithRange(hexStringWithoutHash.startIndex...hexStringWithoutHash.startIndex.advancedBy(1)),
hexStringWithoutHash.substringWithRange(hexStringWithoutHash.startIndex.advancedBy(2)...hexStringWithoutHash.startIndex.advancedBy(3)),
hexStringWithoutHash.substringWithRange(hexStringWithoutHash.startIndex.advancedBy(4)...hexStringWithoutHash.startIndex.advancedBy(5))]
let hexForEach = eachColor.map {CGFloat(Int($0, radix: 16) ?? 0)} //radix is base of numeric system you want to convert to, Hexadecimal has base 16
//return the color by making color
return UIColor(red: hexForEach[0] / 255, green: hexForEach[1] / 255, blue: hexForEach[2] / 255, alpha: alpha)
}
}
用法:
let color = UIColor.colorFromHex("#25ac09")
RGBA版本Swift 3/4
我喜欢卢卡的回答,因为我认为它是最优雅的。
然而,我不希望我的颜色指定在ARGB。我宁愿RGBA +,我也需要在处理字符串的情况下,为每个频道指定1个字符“#FFFA”。
这个版本还增加了错误抛出+剥离'#'字符如果它包含在字符串中。 这是我修改后的Swift表格。
public enum ColourParsingError: Error
{
case invalidInput(String)
}
extension UIColor {
public convenience init(hexString: String) throws
{
let hexString = hexString.replacingOccurrences(of: "#", with: "")
let hex = hexString.trimmingCharacters(in:NSCharacterSet.alphanumerics.inverted)
var int = UInt32()
Scanner(string: hex).scanHexInt32(&int)
let a, r, g, b: UInt32
switch hex.count
{
case 3: // RGB (12-bit)
(r, g, b,a) = ((int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17,255)
//iCSS specification in the form of #F0FA
case 4: // RGB (24-bit)
(r, g, b,a) = ((int >> 12) * 17, (int >> 8 & 0xF) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
case 6: // RGB (24-bit)
(r, g, b, a) = (int >> 16, int >> 8 & 0xFF, int & 0xFF,255)
case 8: // ARGB (32-bit)
(r, g, b, a) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
default:
throw ColourParsingError.invalidInput("String is not a valid hex colour string: \(hexString)")
}
self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255)
}
}