NSRegularExpression问题

Question

我正在使用NSRegularExpression来读取文本并查找hashtag。这是我在regularExpressionWithPattern中使用的NSString。

- (NSString *)hashtagRegex
{
    return @"#((?:[A-Za-z0-9-_]*))";
    //return @"#{1}([A-Za-z0-9-_]{2,})";

}

这是我的方法：

 // Handle Twitter Hashtags
  detector = [NSRegularExpression regularExpressionWithPattern:[self hashtagRegex] options:0 error:&error];
  links = [detector matchesInString:theText options:0 range:NSMakeRange(0, theText.length)];
  current = [NSMutableArray arrayWithArray:links];

    NSString *hashtagURL =   @"http://twitter.com/search?q=%23";
  //hashtagURL = [hashtagURL stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];

  for ( int i = 0; i < [links count]; i++ ) {

    NSTextCheckingResult *cr = [current objectAtIndex:i];

    NSString *url = [theText substringWithRange:cr.range];

    NSString *nohashURL = [url stringByReplacingOccurrencesOfString:@"#" withString:@""];
    nohashURL = [nohashURL stringByReplacingOccurrencesOfString:@" " withString:@""];

    [theText replaceOccurrencesOfString:url 
                             withString:[NSString stringWithFormat:@"<a href=\"%@%@\">%@</a>", hashtagURL, nohashURL, url]
                                options:NSLiteralSearch 
                                  range:NSMakeRange(0, theText.length)];
    current = [NSMutableArray arrayWithArray:[detector matchesInString:theText options:0 range:NSMakeRange(0, theText.length)]];

  }

  [theText replaceOccurrencesOfString:@"\n" withString:@"<br />" options:NSLiteralSearch range:NSMakeRange(0, theText.length)];

  [_aWebView loadHTMLString:[self embedHTMLWithFontName:[self fontName] 
                                                   size:[self fontSize] 
                                                   text:theText]
                    baseURL:nil];

一切都正常，但当我使用这样的字符串时，它解决了一个小问题：

NSString * theText = @"#twitter #twitterapp #twittertag";

我的代码只在每个单词上突出显示#twitter，而不是它的第二部分(#twitter #twitter(app) #twitter(tag))。我希望有人能帮助我！

谢谢您:)

Answer 1

这句话

[theText replaceOccurrencesOfString:url 
                         withString:[NSString stringWithFormat:@"<a href=\"%@%@\">%@</a>", hashtagURL, nohashURL, url]
                            options:NSLiteralSearch 
                              range:NSMakeRange(0, theText.length)];

将字符串url的所有实例替换为替换字符串。在您给出的示例中，第一次遍历循环时，url为@"#twitter"，并且在theText中出现该字符串的所有三次都会被一次性替换。下面是theText的样子：

<a href="http://twitter.com/search?q=%23twitter">#twitter</a> <a href="http://twitter.com/search?q=%23twitter">#twitter</a>app <a href="http://twitter.com/search?q=%23twitter">#twitter</a>tag

所以，当然，在接下来的两次循环中，结果并不完全是你所期望的…好了！

我认为解决办法是限制替换的范围：

[theText replaceOccurrencesOfString:url 
                         withString:[NSString stringWithFormat:@"<a href=\"%@%@\">%@</a>", hashtagURL, nohashURL, url]
                            options:NSLiteralSearch 
                              range:cr.range];