How to convert UIColor to HEX and display in NSLog

Swift 5:

func hexStringFromColor(color: UIColor) -> String {    let components = color.cgColor.components    let r: CGFloat = components?[0] ?? 0.0    let g: CGFloat = components?[1] ?? 0.0    let b: CGFloat = components?[2] ?? 0.0    let hexString = String.init(format: "#%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)), lroundf(Float(b * 255)))    print(hexString)    return hexString }func colorWithHexString(hexString: String) -> UIColor {    var colorString = hexString.trimmingCharacters(in: .whitespacesAndNewlines)    colorString = colorString.replacingOccurrences(of: "#", with: "").uppercased()    print(colorString)    let alpha: CGFloat = 1.0    let red: CGFloat = self.colorComponentFrom(colorString: colorString, start: 0, length: 2)    let green: CGFloat = self.colorComponentFrom(colorString: colorString, start: 2, length: 2)    let blue: CGFloat = self.colorComponentFrom(colorString: colorString, start: 4, length: 2)    let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)    return color}func colorComponentFrom(colorString: String, start: Int, length: Int) -> CGFloat {    let startIndex = colorString.index(colorString.startIndex, offsetBy: start)    let endIndex = colorString.index(startIndex, offsetBy: length)    let subString = colorString[startIndex..<endIndex]    let fullHexString = length == 2 ? subString : "\(subString)\(subString)"    var hexComponent: UInt32 = 0    guard Scanner(string: String(fullHexString)).scanHexInt32(&hexComponent) else {        return 0    }    let hexFloat: CGFloat = CGFloat(hexComponent)    let floatValue: CGFloat = CGFloat(hexFloat / 255.0)    print(floatValue)    return floatValue}

How to use

let red =  CGFloat(30.0)let green =  CGFloat(171.0)let blue =  CGFloat(13.0)let alpha =  CGFloat(1.0)let color = UIColor(red: CGFloat(red/255.0), green: CGFloat(green/255.0), blue: CGFloat(blue / 255.0), alpha: alpha)let colorCode = self.hexStringFromColor(color: color)print(colorCode)let resultColor = self.colorWithHexString(hexString: colorCode)print(resultColor)

Objective-C:

- (NSString *)hexStringFromColor:(UIColor *)color {    const CGFloat *components = CGColorGetComponents(color.CGColor);    CGFloat r = components[0];    CGFloat g = components[1];    CGFloat b = components[2];    return [NSString stringWithFormat:@"#%02lX%02lX%02lX",            lroundf(r * 255),            lroundf(g * 255),            lroundf(b * 255)];}

After getting hex code string, Call below method to get UIColor

- (UIColor *) colorWithHexString: (NSString *) hexString{    NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];    NSLog(@"colorString :%@",colorString);    CGFloat alpha, red, blue, green;    // #RGB    alpha = 1.0f;    red   = [self colorComponentFrom: colorString start: 0 length: 2];    green = [self colorComponentFrom: colorString start: 2 length: 2];    blue  = [self colorComponentFrom: colorString start: 4 length: 2];    return [UIColor colorWithRed: red green: green blue: blue alpha: alpha];}- (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length {    NSString *substring = [string substringWithRange: NSMakeRange(start, length)];    NSString *fullHex = length == 2 ? substring : [NSString stringWithFormat: @"%@%@", substring, substring];    unsigned hexComponent;    [[NSScanner scannerWithString: fullHex] scanHexInt: &hexComponent];    return hexComponent / 255.0;}

How to use

// ( R = 30, G = 171, B = 13)? CGFloat red = 30.0;CGFloat green = 171.0;CGFloat blue = 13.0; CGFloat alpha = 255.0UIColor *color = [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:(alpha/255.0)];NSString *colorCode = [self hexStringFromColor:color];NSLog(@"Color Code: %@", colorCode);UIColor *resultColor = [self colorWithHexString:colorCode];

And finally the version which works with alpha-component and uses right multiplier

extension UIColor {    var hexString: String? {        var red: CGFloat = 0        var green: CGFloat = 0        var blue: CGFloat = 0        var alpha: CGFloat = 0        let multiplier = CGFloat(255.999999)        guard self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) else {            return nil        }        if alpha == 1.0 {            return String(                format: "#%02lX%02lX%02lX",                Int(red * multiplier),                Int(green * multiplier),                Int(blue * multiplier)            )        }        else {            return String(                format: "#%02lX%02lX%02lX%02lX",                Int(red * multiplier),                Int(green * multiplier),                Int(blue * multiplier),                Int(alpha * multiplier)            )        }    }}

Kampai's answer works for RGB colors, but not for monochrome (UIColor colorWithWhite:alpha:). It also doesn't handle alpha, which HEX supports. Here's a slightly modified version of hexStringFromColor:

+ (NSString *)hexStringFromColor:(UIColor *)color{    CGColorSpaceModel colorSpace = CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor));    const CGFloat *components = CGColorGetComponents(color.CGColor);    CGFloat r, g, b, a;    if (colorSpace == kCGColorSpaceModelMonochrome) {        r = components[0];        g = components[0];        b = components[0];        a = components[1];    }    else if (colorSpace == kCGColorSpaceModelRGB) {        r = components[0];        g = components[1];        b = components[2];        a = components[3];    }    return [NSString stringWithFormat:@"#%02lX%02lX%02lX%02lX",            lroundf(r * 255),            lroundf(g * 255),            lroundf(b * 255),            lroundf(a * 255)];}