Convert hex color to UIColor

UIColor+Hex.h

//
//  UIColor+Hex.h
//  Gists
//
//  Created by Andrey Streltsov on 24 Dec 2014.
//  Copyright (c) 2014 Scopicsoftware. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIColor (Hex)

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

@end

UIColor+Hex.mm

//
//  UIColor+Hex.mm
//  Gists
//
//  Created by Andrey Streltsov on 24 Dec 2014.
//  Copyright (c) 2014 Scopicsoftware. All rights reserved.
//

#import "UIColor+Hex.h"

@implementation UIColor (Hex)

+ (UIColor *)colorFromHexString:(NSString *)hexString {

    // Check for hash and add the missing hash
    if('#' != [hexString characterAtIndex:0])
    {
        hexString = [NSString stringWithFormat:@"#%@", hexString];
    }

    // check for string length
    NSAssert(7 == hexString.length || 4 == hexString.length, @"check for string length");

    // check for 3 character HexStrings
    hexString = [self hexStringTransformFromThreeCharacters:hexString];

    NSString *redHex    = [NSString stringWithFormat:@"0x%@", [hexString substringWithRange:NSMakeRange(1, 2)]];
    unsigned redInt = [self hexValueToUnsigned:redHex];

    NSString *greenHex  = [NSString stringWithFormat:@"0x%@", [hexString substringWithRange:NSMakeRange(3, 2)]];
    unsigned greenInt = [self hexValueToUnsigned:greenHex];

    NSString *blueHex   = [NSString stringWithFormat:@"0x%@", [hexString substringWithRange:NSMakeRange(5, 2)]];
    unsigned blueInt = [self hexValueToUnsigned:blueHex];

    UIColor *color = [UIColor colorWith8BitRed:redInt green:greenInt blue:blueInt alpha:1.0];

    return color;
}

+ (UIColor *)colorWith8BitRed:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue alpha:(CGFloat)alpha
{
    UIColor *color = nil;

    color = [UIColor colorWithRed:(float)red/255 green:(float)green/255 blue:(float)blue/255 alpha:alpha];

    return color;
}


+ (NSString *)hexStringTransformFromThreeCharacters:(NSString *)hexString
{
    if(hexString.length == 4)
    {
        hexString = [NSString stringWithFormat:@"#%@%@%@%@%@%@",
                                               [hexString substringWithRange:NSMakeRange(1, 1)],[hexString substringWithRange:NSMakeRange(1, 1)],
                                               [hexString substringWithRange:NSMakeRange(2, 1)],[hexString substringWithRange:NSMakeRange(2, 1)],
                                               [hexString substringWithRange:NSMakeRange(3, 1)],[hexString substringWithRange:NSMakeRange(3, 1)]];
    }

    return hexString;
}

+ (unsigned)hexValueToUnsigned:(NSString *)hexValue
{
    unsigned value = 0;

    NSScanner *hexValueScanner = [NSScanner scannerWithString:hexValue];
    [hexValueScanner scanHexInt:&value];

    return value;
}


@end