1

im pretty new in ios development and im tryin to parse an RSS file(xml).

here is the xml: (sorry for the language)

<item>
<category> General < / category >
<title> killed in a tractor accident , was critically injured windsurfer </ title>
<description>
< ! [ CDATA [
<div> <a href='http://www.ynet.co.il/articles/0,7340,L-4360016,00.html'> <img src = 'http://www.ynet.co. il/PicServer3/2012/11/28/4302844/YOO_8879_a.jpg ' alt =' photo: Yaron Brener 'title =' Amona 'border = '0' width = '116 'height = '116'> </ a> < / div >
] ] >
Tractor driver in his 50s near Kfar Yuval flipped and trapped underneath . Room was critically injured windsurfer hurled rocks because of strong winds and wind surfer after was moderately injured in Netanya
< / description >
<link>
http://www.ynet.co.il/articles/0 , 7340, L- 4360016 , 00.html
< / link >
<pubDate> Fri, 22 Mar 2013 17:10:15 +0200 </ pubDate>
<guid>
http://www.ynet.co.il/articles/0 , 7340, L- 4360016 , 00.html
< / guid >
<tags> Kill , car accidents , surfing < / tags >
< / item >

and here is my xmlparser code:

    - (void)parserDidStartDocument:(NSXMLParser *)parser
    {
       self.titles = [[NSMutableArray alloc]init];
       self.descriptions = [[NSMutableArray alloc]init];
        self.links = [[NSMutableArray alloc]init];
    }

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"item"]) {
        isItem = YES;
    }

    if ([elementName isEqualToString:@"title"]) {
        isTitle=YES;
        self.titlesString = [[NSMutableString alloc]init];
    }

    if ([elementName isEqualToString:@"description"]) {
        isDesription = YES;
        self.descriptionString = [NSMutableString string];
        self.data = [NSMutableData data];
    }



}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
    if(isItem && isTitle){
        [self.titlesString appendString:string];
    }
    if (isItem && isDesription) {
        if (self.descriptionString)
            [self.descriptionString appendString:string];
    }






}

- (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock
{
    if (self.data)
        [self.data appendData:CDATABlock];

}


- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    if ([elementName isEqualToString:@"item"]) {
        isItem = NO;
        [self.titles addObject:self.titlesString];

        [self.descriptions addObject:self.descriptionString];


    }

    if ([elementName isEqualToString:@"title"]) {
        isTitle=NO;

    }
    if ([elementName isEqualToString:@"description"]) {

        NSString *result = [self.descriptionString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
        NSLog(@"string=%@", result);


        if ([self.data length] > 0)
        {
            NSString *htmlSnippet = [[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding];
            NSString *imageSrc = [self firstImgUrlString:htmlSnippet];
            NSLog(@"img src=%@", imageSrc);
            [self.links addObject:imageSrc];
        }



        self.descriptionString = nil;
        self.data = nil;
    }


}

- (NSString *)firstImgUrlString:(NSString *)string
{
    NSError *error = NULL;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(<img\\s[\\s\\S]*?src\\s*?=\\s*?['\"](.*?)['\"][\\s\\S]*?>)+?"
                                                                           options:NSRegularExpressionCaseInsensitive
                                                                             error:&error];

    NSTextCheckingResult *result = [regex firstMatchInString:string
                                                     options:0
                                                       range:NSMakeRange(0, [string length])];

    if (result)
        return [string substringWithRange:[result rangeAtIndex:2]];

    return nil;
}

@end

Like I said I'm pretty new to iPhone development, I looked for ways to solve it for several hours but found nothing. I decided to open a topic, then a few questions:

One. The parser does not ignore what CDATA is just doing parse everything. Why is this happening? As you can see the description itself is not in cdata and I I have only the first step but I get the rest even when I'm not using foundCDATA: (NSData *) CDATABlock

Two. I want to take the image link, how to do it? I searched online and found a lot of guide explains only use the function foundCDATA: (NSData *) CDATABlock But how is it used? The way in which I used in the code?

Please I need an explanation so I can understand, thank you!

4

3 回答 3

1

回答你的两个问题：

  1. 如果您已实现foundCDATA，解析器将在该方法中解析descriptionCDATA，而不是在foundCharacters. 另一方面，如果您还没有实现foundCDATA，CDATA将被 解析foundCharacters。所以，如果你不想foundCharacters解析CDATA，那么你必须实现foundCDATA.

  2. 如果要提取imgURL，则必须以某种方式解析收到的 HTML。您可以使用 Hpple，但我可能只是倾向于使用正则表达式：

    - (NSString *)firstImgUrlString:(NSString *)string
{
    NSError *error = NULL;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(<img\\s[\\s\\S]*?src\\s*?=\\s*?['\"](.*?)['\"][\\s\\S]*?>)+?"
                                                                           options:NSRegularExpressionCaseInsensitive
                                                                             error:&error];

    NSTextCheckingResult *result = [regex firstMatchInString:string
                                                     options:0
                                                       range:NSMakeRange(0, [string length])];

    if (result)
        return [string substringWithRange:[result rangeAtIndex:2]];

    return nil;
}

    另请参阅另一个 Stack Overflow 答案，我在其中演示了 Hpple 和正则表达式解决方案：

例如，以下是NSXMLParserDelegate解析描述的方法，将文本（不包括 CDATA）放在一个字段中，并将 CDATA 中的图像 URL 放在另一个变量中。您必须进行修改以适应您的流程，但希望这可以为您提供基本思路：

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"description"])
    {
        self.string = [NSMutableString string];
        self.data = [NSMutableData data];
    }
}

- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
    NSLog(@"%s, parseError=%@", __FUNCTION__, parseError);
}

// In my standard NSXMLParser routine, I leave self.string `nil` when not parsing 
// a particular element, and initialize it if I am parsing. I do it this way
// so only my `didStartElement` and `didEndElement` need to worry about the particulars
// and my `foundCharacters` and `foundCDATA` are simplified. But do it however you
// want.

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    if (self.string)
        [self.string appendString:string];
}

- (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock
{
    if (self.data)
        [self.data appendData:CDATABlock];
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    if ([elementName isEqualToString:@"description"])
    {
        // get the text (non-CDATA) portion

        // you might want to get rid of the leading and trailing whitespace

        NSString *result = [self.string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
        NSLog(@"string=%@", result);

        // get the img out of the CDATA

        if ([self.data length] > 0)
        {
            NSString *htmlSnippet = [[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding];
            NSString *imageSrc = [self firstImgUrlString:htmlSnippet];
            NSLog(@"img src=%@", imageSrc);
        }

        // once I've saved the data where I want to save it, I `nil` out my
        // `string` and `data` properties:

        self.string = nil;
        self.data = nil;
    }
}
于 2013-03-22T18:18:41.027 回答
0

您要提取的图像链接位于 CDATA 块内，但 rss 解析器会忽略 CDATA 块。

如果你需要从 CDATA 中提取字符串，你可以在 foundCDATA 中使用这个块：

    - (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock
    {

    NSMutableString *cdstring = [[NSMutableString alloc] initWithData:CDATABlock encoding:NSUTF8StringEncoding];
    }

现在可变字符串“cdstring”将包含：

    <div>
    <a href='http://www.ynet.co.il/articles/0,7340,L-4360016,00.html'>
    <img src='http://www.ynet.co. il/PicServer3/2012/11/28/4302844/YOO_8879_a.jpg ' alt=' photo: Yaron Brener ' title=' Amona ' border='0' width='116 ' height='116'>
    </ a>
    </ div>
    ]]>

现在只需使用 stringcontainsstring 搜索 href=' 并提取链接或使用 webview 来显示

 htmlContent = [NSString stringWithFormat:@"%@", cdstring];
    [webView loadHTMLString:htmlContent baseURL:nil];
于 2014-01-09T11:46:15.823 回答
0

答案 1：我会同意 Rob 对这个问题的回答。

答案2：试试这个来获取图片链接....

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{   
    if([currentElement isEqualToString:@"img"]) {
        NSLog(@"%@",[attributeDict objectForKey:@"src"]);
    }
}
于 2013-03-22T19:33:08.343 回答