Objective C - UIColor

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UIColor+Hex.h

#import <UIKit/UIKit.h> @interface UIColor (Hex) + (UIColor *) colorWithHexString: (NSString *) hexString;+ (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length; @end

UIColor+Hex.m

#import "UIColor+Hex.h" @interface UIColor() + (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length; @end  @implementation UIColor(HexString) + (UIColor *) colorWithHexString: (NSString *) hexString{    NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];    CGFloat alpha, red, blue, green;    switch ([colorString length]) {        case 3: // #RGB            alpha = 1.0f;            red   = [self colorComponentFrom: colorString start: 0 length: 1];            green = [self colorComponentFrom: colorString start: 1 length: 1];            blue  = [self colorComponentFrom: colorString start: 2 length: 1];            break;        case 4: // #ARGB            alpha = [self colorComponentFrom: colorString start: 0 length: 1];            red   = [self colorComponentFrom: colorString start: 1 length: 1];            green = [self colorComponentFrom: colorString start: 2 length: 1];            blue  = [self colorComponentFrom: colorString start: 3 length: 1];            break;        case 6: // #RRGGBB            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];            break;        case 8: // #AARRGGBB            alpha = [self colorComponentFrom: colorString start: 0 length: 2];            red   = [self colorComponentFrom: colorString start: 2 length: 2];            green = [self colorComponentFrom: colorString start: 4 length: 2];            blue  = [self colorComponentFrom: colorString start: 6 length: 2];            break;        default:            [NSException raise:@"Invalid color value" format: @"Color value %@ is invalid.  It should be a hex value of the form #RBG, #ARGB, #RRGGBB, or #AARRGGBB", hexString];            break;    }    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;} @end

Objective C - UIColor