NSString删除html标签，保留< brackets>中的文本

Question

如何从NSString中删除html标记，但保留任何<Text in angle brackets>

像<p>123 <Hello> abc</p> -> 123 <Hello> abc

我尝试过所有类型的regexp、scanner和XML Parser解决方案，但它们删除了<Text in angle brackets>和标签。

唯一适合我的解决方案是使用带选项的NSAttributedString

NSAttributedString *str = [[NSAttributedString alloc] initWithData:utf8Data
                                                               options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType,
                                                                         NSCharacterEncodingDocumentAttribute: @(NSUTF8StringEncoding)}
                                                    documentAttributes:nil
                                                                 error:nil];

NSString *result = [str string];

但是这种方法使用了WebKit，并且为我的任务消耗了太多的内存。

那么，如何从NSString中剥离标记，而不使用任何类型的WebKit/UIWebView等来保留<Text in angle brackets>呢？

Answer 1

我前段时间问了一个similar questionma，可能有一些答案可以帮到你。如果您确实需要完整的超文本标记语言解析器，并且只想剥离超文本标记语言标记，那么NSString类别可能会很有用(这个类别是mwaterfal修改后的类别)：

- (NSString *)stringByStrippingTags {

    // Find first & and short-cut if we can
    NSUInteger ampIndex = [self rangeOfString:@"<" options:NSLiteralSearch].location;
    if (ampIndex == NSNotFound) {
        return [NSString stringWithString:self]; // return copy of string as no tags found
    }

    // Scan and find all tags
    NSScanner *scanner = [NSScanner scannerWithString:self];
    [scanner setCharactersToBeSkipped:nil];
    NSMutableSet *tags = [[NSMutableSet alloc] init];
    NSString *tag;
    do {
        // Scan up to <
        tag = nil;
        [scanner scanUpToString:@"<" intoString:NULL];
        [scanner scanUpToString:@">" intoString:&tag];

        if (tag) {
            NSString *t = [[NSString alloc] initWithFormat:@"%@>", tag];
            [tags addObject:t];
        }

    } while (![scanner isAtEnd]);
    NSMutableString *result = [[NSMutableString alloc] initWithString:self];
    NSString *finalString;

    NSString *replacement;
    for (NSString *t in tags) {
        replacement = @" ";
        if ([t isEqualToString:@"<a>"] ||
            [t isEqualToString:@"</a>"] ||
            [t isEqualToString:@"<span>"] ||
            [t isEqualToString:@"</span>"] ||
            [t isEqualToString:@"<strong>"] ||
            [t isEqualToString:@"</strong>"] ||
            [t isEqualToString:@"<em>"] ||
            [t isEqualToString:@"</em>"]) {
            replacement = @"";
        }
        [result replaceOccurrencesOfString:t
                            withString:replacement
                               options:NSLiteralSearch
                                 range:NSMakeRange(0, result.length)];
    }

    // Remove multi-spaces and line breaks
    return = [result stringByRemovingNewLinesAndWhitespace];
}