5

我正在使用一种将 html 文本解析为 NSString 的开源方法。

生成的字符串在前几段之间有大量空白，但后续段落只有一行空间。这是一个输出示例。

在此处输入图像描述 以下是我正在调用的方法。我只更改了两行代码。对于stopCharactersand newLineAndWhitespaceCharacters，我/n从字符集中删除了，因为当它被包含在内时，整个文本就是一个长段落。

- (NSString *)stringByConvertingHTMLToPlainText {

    // Pool
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    // Character sets
    NSCharacterSet *stopCharacters = [NSCharacterSet characterSetWithCharactersInString:[NSString stringWithFormat:@"< \t\r%C%C%C%C", 0x0085, 0x000C, 0x2028, 0x2029]];
    NSCharacterSet *newLineAndWhitespaceCharacters = [NSCharacterSet characterSetWithCharactersInString:[NSString stringWithFormat:@" \t\r%C%C%C%C", 0x0085, 0x000C, 0x2028, 0x2029]];
    NSCharacterSet *tagNameCharacters = [NSCharacterSet characterSetWithCharactersInString:@"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"];

    // Scan and find all tags
    NSMutableString *result = [[NSMutableString alloc] initWithCapacity:self.length];
    NSScanner *scanner = [[NSScanner alloc] initWithString:self];
    [scanner setCharactersToBeSkipped:nil];
    [scanner setCaseSensitive:YES];
    NSString *str = nil, *tagName = nil;
    BOOL dontReplaceTagWithSpace = NO;
    do {

        // Scan up to the start of a tag or whitespace
        if ([scanner scanUpToCharactersFromSet:stopCharacters intoString:&str]) {
            [result appendString:str];
            str = nil; // reset
        }

        // Check if we've stopped at a tag/comment or whitespace
        if ([scanner scanString:@"<" intoString:NULL]) {

            // Stopped at a comment or tag
            if ([scanner scanString:@"!--" intoString:NULL]) {

                // Comment
                [scanner scanUpToString:@"-->" intoString:NULL];
                [scanner scanString:@"-->" intoString:NULL];

            } else {

                // Tag - remove and replace with space unless it's
                // a closing inline tag then dont replace with a space
                if ([scanner scanString:@"/" intoString:NULL]) {

                    // Closing tag - replace with space unless it's inline
                    tagName = nil; dontReplaceTagWithSpace = NO;
                    if ([scanner scanCharactersFromSet:tagNameCharacters intoString:&tagName]) {
                        tagName = [tagName lowercaseString];
                        dontReplaceTagWithSpace = ([tagName isEqualToString:@"a"] ||
                                                   [tagName isEqualToString:@"b"] ||
                                                   [tagName isEqualToString:@"i"] ||
                                                   [tagName isEqualToString:@"q"] ||
                                                   [tagName isEqualToString:@"span"] ||
                                                   [tagName isEqualToString:@"em"] ||
                                                   [tagName isEqualToString:@"strong"] ||
                                                   [tagName isEqualToString:@"cite"] ||
                                                   [tagName isEqualToString:@"abbr"] ||
                                                   [tagName isEqualToString:@"acronym"] ||
                                                   [tagName isEqualToString:@"label"]);
                    }

                    // Replace tag with string unless it was an inline
                    if (!dontReplaceTagWithSpace && result.length > 0 && ![scanner isAtEnd]) [result appendString:@" "];

                }

                // Scan past tag
                [scanner scanUpToString:@">" intoString:NULL];
                [scanner scanString:@">" intoString:NULL];

            }

        } else {

            // Stopped at whitespace - replace all whitespace and newlines with a space
            if ([scanner scanCharactersFromSet:newLineAndWhitespaceCharacters intoString:NULL]) {
                if (result.length > 0 && ![scanner isAtEnd]) [result appendString:@" "]; // Dont append space to beginning or end of result
            }

        }

    } while (![scanner isAtEnd]);

    // Cleanup
    [scanner release];

    // Decode HTML entities and return
    NSString *retString = [[result stringByDecodingHTMLEntities] retain];
    [result release];

    // Drain
    [pool drain];

    // Return
    return [retString autorelease];

}

编辑：

这是字符串的 NSLog。我只粘贴了前几段

Mitt Romney spent the past six years running for president. After his loss to President Barack Obama, he'll have to chart a different course.  


 His initial plan: spend time with his family. He has five sons and 18 grandchildren, with a 19th on the way.  






 "I don't look at postelection to be a time of regrouping. Instead it's a time of forward focus," Romney told reporters aboard his plane Tuesday evening as he returned to Boston after the final campaign stop of his political career. "I have, of course, a family and life important to me, win or lose."  

 The most visible member of that family — wife Ann Romney — says neither she nor her husband will seek political office again.

ETC....

for (int j = 25; j< 50; j++) {
    char test =  [completeTrimmed characterAtIndex:([completeTrimmed rangeOfString:@"chart a different course."].location + j)];

        NSLog(@"%hhd", test);
    }

012-11-11 17:15:57.668 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.669 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.669 LMU_LAL_LAUNCHER[5431:c07] 10
2012-11-11 17:15:57.670 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.670 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.670 LMU_LAL_LAUNCHER[5431:c07] 10
2012-11-11 17:15:57.671 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.671 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.671 LMU_LAL_LAUNCHER[5431:c07] 10
2012-11-11 17:15:57.672 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.672 LMU_LAL_LAUNCHER[5431:c07] 72
2012-11-11 17:15:57.672 LMU_LAL_LAUNCHER[5431:c07] 105
2012-11-11 17:15:57.673 LMU_LAL_LAUNCHER[5431:c07] 115
2012-11-11 17:15:57.673 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.673 LMU_LAL_LAUNCHER[5431:c07] 105
2012-11-11 17:15:57.673 LMU_LAL_LAUNCHER[5431:c07] 110
2012-11-11 17:15:57.674 LMU_LAL_LAUNCHER[5431:c07] 105
2012-11-11 17:15:57.674 LMU_LAL_LAUNCHER[5431:c07] 116
2012-11-11 17:15:57.674 LMU_LAL_LAUNCHER[5431:c07] 105
2012-11-11 17:15:57.675 LMU_LAL_LAUNCHER[5431:c07] 97
2012-11-11 17:15:57.675 LMU_LAL_LAUNCHER[5431:c07] 108
2012-11-11 17:15:57.675 LMU_LAL_LAUNCHER[5431:c07] 32
2012-11-11 17:15:57.675 LMU_LAL_LAUNCHER[5431:c07] 112
2012-11-11 17:15:57.676 LMU_LAL_LAUNCHER[5431:c07] 108
2012-11-11 17:15:57.676 LMU_LAL_LAUNCHER[5431:c07] 97
4

3 回答 3

4

检查这个，

  //Decode HTML entities and return
  NSString *retString = [result stringByDecodingHTMLEntities];
  [result release];

  //Drain
  [pool drain];

  retString = [[retString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] retain];

  //Return
  return [retString autorelease];   
}

如果上述方法不起作用，请尝试使用

completeTrimmed = [completeTrimmed stringByReplacingOccurrencesOfString:@"\n" withString:@""];

和

completeTrimmed = [completeTrimmed stringByReplacingOccurrencesOfString:@"\r" withString:@""];
于 2012-11-11T04:29:00.350 回答
2

您可以将 @"/n/n" 替换为 @"/n" 以减少换行符的数量。

于 2012-11-18T23:05:26.827 回答
1

我已经尝试过上面的问题，这就是我解决它的方法，

NSString *retString = [[result stringByDecodingHTMLEntities] retain];
[result release];

retString = [retString stripDuplicateCharactersInSet:[NSCharacterSet whitespaceCharacterSet] withString:@" "];
retString = [retString stripDuplicateCharactersInSet:[NSCharacterSet newlineCharacterSet] withString:@"\n"];

我在 NSString 上定义了一个类别方法，

- (NSString *)stripDuplicateCharactersInSet:(NSCharacterSet *)characterSet withString:(NSString *)joiningString;

实现如下，

- (NSString *)stripDuplicateCharactersInSet:(NSCharacterSet *)characterSet withString:(NSString *)joiningString {

    NSMutableString *originalStr = [NSMutableString string];

    if (!self) {
        return nil;
    }

    NSArray *componentsArray = [self componentsSeparatedByCharactersInSet:characterSet];

    int counter = 0;
    for (NSString *stringComponent in componentsArray) {

        counter ++;

        if ((stringComponent) && ([stringComponent length] > 0) && (![stringComponent isEqualToString:@" "]) && ((![stringComponent isEqualToString:@"\n"]) || (![joiningString isEqualToString:@"\n"]))) {

            if ([componentsArray count] == counter) {
                [originalStr appendFormat:@"%@", stringComponent];                
            } else {
                [originalStr appendFormat:@"%@%@", stringComponent, joiningString];
            }
        }
    }

    return originalStr;
}

将上述方法添加到NSString+HTML.m文件中作为NSString. 基本上在你给出的 html 中，空格和换行符被混合了多次，并且试图单独去除换行符是行不通的。因此，我通过比较字符串在剥离后是否具有换行符或空格然后附加到主字符串来删除重复的换行符和空格，如上所示。

或者，您也可以尝试，

NSString *retString = [[result stringByDecodingHTMLEntities] retain];
[result release];

retString = [retString stripDuplicateNewlineCharacters];

该方法定义为，

- (NSString *)stripDuplicateNewlineCharacters {

    NSMutableString *originalStr = [NSMutableString string];

    if (!self) {
        return nil;
    }

    NSArray *componentsArray = [self componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]];

    int counter = 0;
    for (NSString *stringComponent in componentsArray) {

        counter ++;

        stringComponent = [stringComponent stringByReplacingOccurrencesOfString:@" " withString:@"<#$%$#>"];
        stringComponent = [stringComponent stringByReplacingOccurrencesOfString:@"<#$%$#><#$%$#>" withString:@"<#$%$#>"];
        stringComponent = [stringComponent stringByReplacingOccurrencesOfString:@"<#$%$#>" withString:@" "];

        if ((stringComponent) && ([stringComponent length] > 0) && (![stringComponent isEqualToString:@" "]) && (![stringComponent isEqualToString:@"\n"])) {

            if ([componentsArray count] == counter) {
                [originalStr appendFormat:@"%@", stringComponent];
            } else {
                [originalStr appendFormat:@"%@\n", stringComponent];
            }
        }
    }

    return originalStr;
}

在这种情况下，在方法本身中删除了重复的空格，同时删除了换行符。

于 2012-11-20T02:34:58.883 回答