在字符串中使用枚举属性并为字符串的一部分加下划线

 NSMutableDictionary *attributesDictionary = [NSMutableDictionary dictionary];
 [attributesDictionary setObject:[UIFont systemFontOfSize:14] forKey:NSFontAttributeName];
 //[attributesDictionary setObject:[UIColor redColor] forKey:NSForegroundColorAttributeName];
 NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]initWithString:@"Google www.google.com link" attributes:attributesDictionary];

 [attributedString enumerateAttribute:(NSString *) NSFontAttributeName
                             inRange:NSMakeRange(0, [attributedString length])
                             options:NSAttributedStringEnumerationLongestEffectiveRangeNotRequired
                          usingBlock:^(id value, NSRange range, BOOL *stop) {
                              NSLog(@"Attribute: %@, %@", value, NSStringFromRange(range));
                             }];

  NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc] initWithString:@"www.google.com "];

  [attributedString addAttribute:NSUnderlineStyleAttributeName
                         value:[NSNumber numberWithInt:NSUnderlineStyleDouble]
                         range:NSMakeRange(7, attributedStr.length)];

  [attributedString addAttribute:NSForegroundColorAttributeName
                         value:[UIColor blueColor]
                         range:NSMakeRange(6,attributedStr.length)];

  _attriLbl.attributedText = attributedString;//_attriLbl (of type UILabel) added in storyboard

输出：