16进制转rgb
- (void)colorWithHexString: (NSString *) stringToConvert
{
//去掉前后空格换行符
NSString *cString = [[stringToConvert stringByTrimmingCharactersInSet:[NSCharacterSetwhitespaceAndNewlineCharacterSet]] uppercaseString];
if ([cString hasPrefix:@"0X"])
cString = [cString substringFromIndex:2];
else if ([cString hasPrefix:@"#"])
cString = [cString substringFromIndex:1];
// 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];
unsigned int r, g, b;
[[NSScanner scannerWithString:rString] scanHexInt:&r];
[[NSScanner scannerWithString:gString] scanHexInt:&g];
[[NSScanner scannerWithString:bString] scanHexInt:&b];
NSLog(@"r = %u, g = %u, b = %u",r, g, b);
}