属性字符串NSMutableAttributedString

要实现如下效果：

 NSString * mailString = @"mymail@126.com";
    NSString * mailStringWithQuotes = [NSString stringWithFormat:@"\"%@\"",mailString];

    NSRange colorRange = [mailStringWithQuotes rangeOfString:mailStringWithQuotes];

    NSMutableAttributedString * attString = [[NSMutableAttributedString alloc] initWithString:mailStringWithQuotes];
    [attString addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:colorRange];

    NSRange underLineRange = [mailStringWithQuotes rangeOfString:mailString];
    [attString addAttribute:NSUnderlineStyleAttributeName value:@(NSUnderlineStyleSingle) range:underLineRange];

    self.mailLabel.attributedText = attString;