[ios] ¿Cómo puedo crear un UIColor a partir de una cadena hexagonal?



Answers

Una solución concisa:

// Assumes input like "#00FF00" (#RRGGBB).
+ (UIColor *)colorFromHexString:(NSString *)hexString {
    unsigned rgbValue = 0;
    NSScanner *scanner = [NSScanner scannerWithString:hexString];
    [scanner setScanLocation:1]; // bypass '#' character
    [scanner scanHexInt:&rgbValue];
    return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
}
Question

¿Cómo puedo crear un UIColor partir de un formato de cadena hexadecimal , como #00FF00 ?




Puede usar varias herramientas en línea para convertir una cadena HEX en UIColor real. Consulte uicolor.org o UI Color Picker . La salida se convertiría en código Objective-C, como:

[UIColor colorWithRed:0.93 green:0.80 blue:0.80 alpha:1.0];

Que podría incrustar en su aplicación. ¡Espero que esto ayude!




Swift equivalente a la respuesta de @ Tom, aunque recibe el valor RGBA Int para admitir la transparencia:

func colorWithHex(aHex: UInt) -> UIColor
{
    return UIColor(red: CGFloat((aHex & 0xFF000000) >> 24) / 255,
        green: CGFloat((aHex & 0x00FF0000) >> 16) / 255,
        blue: CGFloat((aHex & 0x0000FF00) >> 8) / 255,
        alpha: CGFloat((aHex & 0x000000FF) >> 0) / 255)
}

//usage
var color = colorWithHex(0x7F00FFFF)

Y si quieres poder utilizarlo desde una cadena, puedes usar strtoul:

var hexString = "0x7F00FFFF"

let num = strtoul(hexString, nil, 16)

var colorFromString = colorWithHex(num)



Creé un init de conveniencia para eso:

extension UIColor {
convenience init(hex: String, alpha: CGFloat)
{
    let redH = CGFloat(strtoul(hex.substringToIndex(advance(hex.startIndex,2)), nil, 16))
    let greenH = CGFloat(strtoul(hex.substringWithRange(Range<String.Index>(start: advance(hex.startIndex, 2), end: advance(hex.startIndex, 4))), nil, 16))
    let blueH = CGFloat(strtoul(hex.substringFromIndex(advance(hex.startIndex,4)), nil, 16))

    self.init(red: redH/255, green: greenH/255, blue: blueH/255, alpha: alpha)
}
}

entonces puedes crear un UIColor en cualquier lugar de tu proyecto como este:

UIColor(hex: "ffe3c8", alpha: 1)

espero que esto ayude...




Esto es bueno con el soporte de cocoapod

https://github.com/mRs-/HexColors

// with hash
NSColor *colorWithHex = [NSColor colorWithHexString:@"#ff8942" alpha:1];

// wihtout hash
NSColor *secondColorWithHex = [NSColor colorWithHexString:@"ff8942" alpha:1];

// short handling
NSColor *shortColorWithHex = [NSColor colorWithHexString:@"fff" alpha:1]



actualizado para veloz 1.2

class func colorWithHexString (hex:String) -> UIColor {
    var cString: NSString = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString

    if (cString.hasPrefix("#")) {
        cString = cString.substringFromIndex(1)
    }

    if (count(cString as String) != 6) {
        return UIColor.grayColor()
    }

    var rString: String = cString.substringToIndex(2)
    var gString: String = (cString.substringFromIndex(2) as NSString).substringToIndex(2)
    var bString: String = (cString.substringFromIndex(4) as NSString).substringToIndex(2)

    var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0;
    NSScanner(string: rString).scanHexInt(&r)
    NSScanner(string: gString).scanHexInt(&g)
    NSScanner(string: bString).scanHexInt(&b)
    return UIColor(red: CGFloat(Float(r) / 255.0), green: CGFloat(Float(g) / 255.0), blue: CGFloat(Float(b) / 255.0), alpha: CGFloat(1))

}



Usa esta categoría:

en el archivo UIColor + Hexadecimal.h

#import <UIKit/UIKit.h>

@interface UIColor(Hexadecimal)

+ (UIColor *)colorWithHexString:(NSString *)hexString;

@end

en el archivo UIColor + Hexadecimal.m

#import "UIColor+Hexadecimal.h"

@implementation UIColor(Hexadecimal)

+ (UIColor *)colorWithHexString:(NSString *)hexString {
    unsigned rgbValue = 0;
    NSScanner *scanner = [NSScanner scannerWithString:hexString];
    [scanner setScanLocation:1]; // bypass '#' character
    [scanner scanHexInt:&rgbValue];

    return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
}

@end

En Class quieres usarlo:

#import "UIColor+Hexadecimal.h"

y:

[UIColor colorWithHexString:@"#6e4b4b"];



extension UIColor 
{
    class func fromHexaString(hex:String) -> UIColor
    {
        let scanner           = Scanner(string: hex)
        scanner.scanLocation  = 0
        var rgbValue: UInt64  = 0
        scanner.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)
        )
    }
}

//you can call like this.

UIColor.fromHexaString(hex:3276b1)



For swift 2.0+. This code works fine to me.

extension UIColor {
    /// UIColor(hexString: "#cc0000")
    internal convenience init?(hexString:String) {
        guard hexString.characters[hexString.startIndex] == Character("#") else {
            return nil
        }
        guard hexString.characters.count == "#000000".characters.count else {
            return nil
        }
        let digits = hexString.substringFromIndex(hexString.startIndex.advancedBy(1))
        guard Int(digits,radix:16) != nil else{
            return nil
        }
        let red = digits.substringToIndex(digits.startIndex.advancedBy(2))
        let green = digits.substringWithRange(Range<String.Index>(start: digits.startIndex.advancedBy(2),
            end: digits.startIndex.advancedBy(4)))
        let blue = digits.substringWithRange(Range<String.Index>(start:digits.startIndex.advancedBy(4),
            end:digits.startIndex.advancedBy(6)))
        let redf = CGFloat(Double(Int(red, radix:16)!) / 255.0)
        let greenf = CGFloat(Double(Int(green, radix:16)!) / 255.0)
        let bluef = CGFloat(Double(Int(blue, radix:16)!) / 255.0)
        self.init(red: redf, green: greenf, blue: bluef, alpha: CGFloat(1.0))
    }
}

This code includes string format checking. p.ej

let aColor = UIColor(hexString: "#dadada")!
let failed = UIColor(hexString: "123zzzz")

And as far as I know, my code is of no disadvantage for its maintaining the semantic of failible condition and returning an optional value. And this should be the best answer.







Hay una buena publicación sobre cómo abordar la cuestión del OP de extraer un UIColor de una cadena hexagonal. La solución presentada a continuación es diferente de otras porque admite valores de cadena que pueden incluir '0x' o '#' prefijados a la representación de cadena hexadecimal ... (ver uso)

Aquí está el bit principal ...

- (UIColor *)getUIColorObjectFromHexString:(NSString *)hexStr alpha:(CGFloat)alpha
{
  // Convert hex string to an integer
  unsigned int hexint = [self intFromHexString:hexStr];

  // Create color object, specifying alpha as well
  UIColor *color =
    [UIColor colorWithRed:((CGFloat) ((hexint & 0xFF0000) >> 16))/255
    green:((CGFloat) ((hexint & 0xFF00) >> 8))/255
    blue:((CGFloat) (hexint & 0xFF))/255
    alpha:alpha];

  return color;
}

Método de ayuda ...

- (unsigned int)intFromHexString:(NSString *)hexStr
{
  unsigned int hexInt = 0;

  // Create scanner
  NSScanner *scanner = [NSScanner scannerWithString:hexStr];

  // Tell scanner to skip the # character
  [scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"#"]];

  // Scan hex value
  [scanner scanHexInt:&hexInt];

  return hexInt;
}

Uso:

NSString *hexStr1 = @"123ABC";
NSString *hexStr2 = @"#123ABC";
NSString *hexStr3 = @"0x123ABC";

UIColor *color1 = [self getUIColorObjectFromHexString:hexStr1 alpha:.9];
NSLog(@"UIColor: %@", color1);

UIColor *color2 = [self getUIColorObjectFromHexString:hexStr2 alpha:.9];
NSLog(@"UIColor: %@", color2);

UIColor *color3 = [self getUIColorObjectFromHexString:hexStr3 alpha:.9];
NSLog(@"UIColor: %@", color3);

Artículo completo de referencia

Swift 2+

He portado esta solución a Swift 2.2. Tenga en cuenta que he cambiado el parámetro alpha a un valor opcional con un conjunto predeterminado en 1.0. También actualicé el tipo int a UInt32 según lo requerido por la clase NSScanner en Swift 2.2.

func colorWithHexString(hexString: String, alpha:CGFloat? = 1.0) -> UIColor {

    // Convert hex string to an integer
    let hexint = Int(self.intFromHexString(hexString))
    let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
    let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
    let blue = CGFloat((hexint & 0xff) >> 0) / 255.0 
    let alpha = alpha!

    // Create color object, specifying alpha as well
    let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
    return color
}

func intFromHexString(hexStr: String) -> UInt32 {
    var hexInt: UInt32 = 0
    // Create scanner
    let scanner: NSScanner = NSScanner(string: hexStr)
    // Tell scanner to skip the # character
    scanner.charactersToBeSkipped = NSCharacterSet(charactersInString: "#")
    // Scan hex value
    scanner.scanHexInt(&hexInt)
    return hexInt
}

Referencias hexadecimales de color

Códigos y nombres de colores HTML

Códigos de color Hex Color




Aquí hay una versión de Swift 1.2 escrita como una extensión de UIColor . Esto te permite hacer

let redColor = UIColor(hex: "#FF0000")

Lo cual creo que es la forma más natural de hacerlo.

extension UIColor {
  // Initialiser for strings of format '#_RED_GREEN_BLUE_'
  convenience init(hex: String) {
    let redRange    = Range<String.Index>(start: hex.startIndex.advancedBy(1), end: hex.startIndex.advancedBy(3))
    let greenRange  = Range<String.Index>(start: hex.startIndex.advancedBy(3), end: hex.startIndex.advancedBy(5))
    let blueRange   = Range<String.Index>(start: hex.startIndex.advancedBy(5), end: hex.startIndex.advancedBy(7))

    var red     : UInt32 = 0
    var green   : UInt32 = 0
    var blue    : UInt32 = 0

    NSScanner(string: hex.substringWithRange(redRange)).scanHexInt(&red)
    NSScanner(string: hex.substringWithRange(greenRange)).scanHexInt(&green)
    NSScanner(string: hex.substringWithRange(blueRange)).scanHexInt(&blue)

    self.init(
      red: CGFloat(red) / 255,
      green: CGFloat(green) / 255,
      blue: CGFloat(blue) / 255,
      alpha: 1
    )
  }
}



Encontré una buena categoría de UIColor para esto, UIColor+PXExtensions .

Uso: UIColor *mycolor = [UIColor pxColorWithHexValue:@"#BADA55"];

Y, en caso de que el enlace a mi idea principal falle, aquí está el código de implementación real:

//
//  UIColor+PXExtensions.m
//

#import "UIColor+UIColor_PXExtensions.h"

@implementation UIColor (UIColor_PXExtensions)

+ (UIColor*)pxColorWithHexValue:(NSString*)hexValue
{
    //Default
    UIColor *defaultResult = [UIColor blackColor];

    //Strip prefixed # hash
    if ([hexValue hasPrefix:@"#"] && [hexValue length] > 1) {
        hexValue = [hexValue substringFromIndex:1];
    }

    //Determine if 3 or 6 digits
    NSUInteger componentLength = 0;
    if ([hexValue length] == 3)
    {
        componentLength = 1;
    }
    else if ([hexValue length] == 6)
    {
        componentLength = 2;
    }
    else
    {
        return defaultResult;
    }

    BOOL isValid = YES;
    CGFloat components[3];

    //Seperate the R,G,B values
    for (NSUInteger i = 0; i < 3; i++) {
        NSString *component = [hexValue substringWithRange:NSMakeRange(componentLength * i, componentLength)];
        if (componentLength == 1) {
            component = [component stringByAppendingString:component];
        }
        NSScanner *scanner = [NSScanner scannerWithString:component];
        unsigned int value;
        isValid &= [scanner scanHexInt:&value];
        components[i] = (CGFloat)value / 256.0f;
    }

    if (!isValid) {
        return defaultResult;
    }

    return [UIColor colorWithRed:components[0]
                           green:components[1]
                            blue:components[2]
                           alpha:1.0];
}

@end



extension UIColor {
    convenience init(hexaString: String, alpha: CGFloat = 1) {
        let chars = Array(hexaString.characters)
        self.init(red:   CGFloat(strtoul(String(chars[1...2]),nil,16))/255,
                  green: CGFloat(strtoul(String(chars[3...4]),nil,16))/255,
                  blue:  CGFloat(strtoul(String(chars[5...6]),nil,16))/255,
                  alpha: alpha)}
}

Uso:

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



You can use this library

github.com/burhanuddin353/TFTColor

Rápido

UIColor.colorWithRGB(hexString: "FF34AE" alpha: 1.0)

C objetivo

[UIColor colorWithRGBHexString:@"FF34AE" alpha:1.0f]



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