hexa code to UIColor + iphone

- (UIColor *) colorWithHexString: (NSString *) hex 
{ 
    NSString *cString = [[hex stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString]; 
   
    // String should be 6 or 8 characters 
    if ([cString length] < 6) return [UIColor grayColor]; 
   
    // strip 0X if it appears 
    if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2]; 
   
    if ([cString length] != 6) return  [UIColor grayColor]; 
   
    // Separate into r, g, b substrings 
    NSRange range; 
    range.location = 0; 
    range.length = 2; 
    NSString *rString = [cString substringWithRange:range]; 
   
    range.location = 2; 
    NSString *gString = [cString substringWithRange:range]; 
   
    range.location = 4; 
    NSString *bString = [cString substringWithRange:range]; 
   
    // Scan values 
    unsigned int r, g, b; 
    [[NSScanner scannerWithString:rString] scanHexInt:&r]; 
    [[NSScanner scannerWithString:gString] scanHexInt:&g]; 
    [[NSScanner scannerWithString:bString] scanHexInt:&b]; 
   
    return [UIColor colorWithRed:((float) r / 255.0f) 
                           green:((float) g / 255.0f) 
                            blue:((float) b / 255.0f) 
                           alpha:1.0f]; 
}
how to use it
[self.view setBackgroundColor: [self colorWithHexString:@"Ff0000"]];