iOS Creating a UIColor from hexadecimal number or string


Example

You can create a UIColor from a hexadecimal number or string, e.g. 0xff00cc, "#FFFFFF"

Swift

Int Value

extension UIColor {
    convenience init(hex: Int, alpha: CGFloat = 1.0) {
        let r = CGFloat((hex >> 16) & 0xff) / 255
        let g = CGFloat((hex >> 08) & 0xff) / 255
        let b = CGFloat((hex >> 00) & 0xff) / 255
        self.init(red: r, green: g, blue: b, alpha: alpha)
    }
}

Example:

let color = UIColor(hex: 0xff00cc, alpha: 1.0)

Note that for alpha the default value of 1.0 is provided, so it can be used as follows:

let color = UIColor(hex: 0xff00cc)

String Value

extension UIColor {
    convenience init(hexCode: String) {
        let hex = hexCode.stringByTrimmingCharactersInSet(NSCharacterSet.alphanumericCharacterSet().invertedSet)
        var int = UInt32()
        NSScanner(string: hex).scanHexInt(&int)
        let a, r, g, b: UInt32

        switch hex.characters.count {
        case 3:
            (a, r, g, b) = (255, (int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
        case 6:
            (a, r, g, b) = (255, int >> 16, int >> 8 & 0xFF, int & 0xFF)
        case 8:
            (a, r, g, b) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
        default:
            (a, r, g, b) = (1, 1, 1, 0)
        }
    
        self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255)
    }
}

Example Usage:

Hex with alpha

let color = UIColor("#80FFFFFF")

Hex with no alpha (color alpha will equal 1.0)

let color = UIColor("#FFFFFF")
let color = UIColor("#FFF")

Objective-C

Int Value

@interface UIColor (Hex)
+ (UIColor *)colorWithHex:(NSUInteger)hex alpha:(CGFloat)alpha;
@end

@implementation UIColor (Hex)
+ (UIColor *)colorWithHex:(NSUInteger)hex alpha:(CGFloat)alpha {
    return [UIColor colorWithRed:((CGFloat)((hex & 0xFF0000) >> 16))/255.0
                           green:((CGFloat)((hex & 0xFF00) >> 8))/255.0
                            blue:((CGFloat)(hex & 0xFF))/255.0
                           alpha:alpha];
}
@end

Example:

UIColor *color = [UIColor colorWithHex:0xff00cc alpha:1.0];

String Value

- (UIColor*) hex:(NSString*)hexCode {
    
    NSString *noHashString = [hexCode stringByReplacingOccurrencesOfString:@"#" withString:@""];
    NSScanner *scanner = [NSScanner scannerWithString:noHashString];
    [scanner setCharactersToBeSkipped:[NSCharacterSet symbolCharacterSet]];
    
    unsigned hex;
    if (![scanner scanHexInt:&hex]) return nil;
    int a;
    int r;
    int g;
    int b;

    switch (noHashString.length) {
        case 3:
            a = 255;
            r = (hex >> 8) * 17;
            g = ((hex >> 4) & 0xF) * 17;
            b = ((hex >> 0) & 0xF) * 17;
            break;
        case 6:
            a = 255;
            r = (hex >> 16);
            g = (hex >> 8) & 0xFF;
            b = (hex) & 0xFF;
            break;
        case 8:
            a = (hex >> 24);
            r = (hex >> 16) & 0xFF;
            g = (hex >> 8) & 0xFF;
            b = (hex) & 0xFF;
            break;
            
        default:
            a = 255.0;
            r = 255.0;
            b = 255.0;
            g = 255.0;
            break;
    }

    return [UIColor colorWithRed:r / 255.0f green:g / 255.0f blue:b / 255.0f alpha:a / 255];
}

Example usage:

Hex with alpha

UIColor* color = [self hex:@"#80FFFFFF"];

Hex with no alpha (color alpha will equal 1)

UIColor* color = [self hex:@"#FFFFFF"];
UIColor* color = [self hex:@"#FFF"];