开源html解析类没有正确解析段落之间的空格

Mah*_*hir 5 objective-c html-parsing

我正在使用一个将html文本解析为NSString的开源方法.

结果字符串在前两段之间有大量的空格,但后续段落只有一行空格.这是一个输出的例子.

在此输入图像描述 以下是我打电话的方法.我只改变了两行代码.对于stopCharactersnewLineAndWhitespaceCharacters,我/n从characterset中删除,因为当它被包含时,整个文本是一个长段.

- (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];

}
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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.  
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等等....

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
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iDe*_*Dev 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"];
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我在 NSString 上定义了一个类别方法,

- (NSString *)stripDuplicateCharactersInSet:(NSCharacterSet *)characterSet withString:(NSString *)joiningString;
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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;
}
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将上述方法NSString+HTML.m作为类别添加到文件中NSString。基本上在你给出的html中,空格和换行符被混合多次,并且尝试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];
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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;
}
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在这种情况下,方法本身会删除重复的空格,同时删除换行符。