iOS: Create UIColor Object From A Hex String (NSString)

If you need to convert a hex value stored in an NSString into a UIColor object, you’ve come to the right place.

As an example, assume you have the value @”0A5CEA” and need a UIColor object that represents the value of the string. With the code below, creating the UIColor object is as easy as:

UIColor *color = [self getUIColorObjectFromHexString:@"0A5CEA" alpha:.9];

Notice that I also provide a parameter to set the alpha value.

The code also supports hex values in the format @”0x0A5CEA” or @”#0A5CEA” (where the later is common in web development).

Convert Hex String To Integer

The first step is to convert the hex value stored as string into an integer. I covered the specifics of this in the post Convert Hex Value Stored As NSString To Integer.

The code is duplicated here:

- (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; }

The code below uses the integer value of the hex string to create a UIColor object by doing a bitwise ‘&’ operation to isolate the various color attributes and divide each by 255 to get the float value:

- (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; }

The code below shows a few iterations:

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);

As expected, the output for each hex string is the same:

UIColor: UIDeviceRGBColorSpace 0.0705882 0.227451 0.737255 0.9
UIColor: UIDeviceRGBColorSpace 0.0705882 0.227451 0.737255 0.9
UIColor: UIDeviceRGBColorSpace 0.0705882 0.227451 0.737255 0.9