ios - 如何通过xml解析访问图像？

Question

在我的 ios 应用程序中，我尝试从以下 XMl 文件访问图像我怎样才能获取<description>中的图像标签？

<channel>
          <title>Gomolo Photo Gallery</title>
          <link>http://www.gomolo.com/</link>
          <description>Movie stills and Celebrity Wallpapers on Gomolo.com</description>
          <language>en</language>
          <lastBuildDate>6/4/2013 10:20:40 AM</lastBuildDate>
          <image>
                 <url>http://img1.gomolo.com/images/logos/gomolo_M.jpg</url>
                 <title>Gomolo Photo Gallery</title>
                 <link>http://www.gomolo.com/</link>
             </image>
          <ttl>360</ttl>
          <atom10:link xmlns:atom10="http://www.w3.org/2005/Atom" rel="self" type="application/rss+xml" href="http://feeds.feedburner.com/GomoloPhoto"></atom10:link>
          <feedburner:info uri="gomolophoto"></feedburner:info>
          <atom10:link xmlns:atom10="http://www.w3.org/2005/Atom" rel="hub" href="http://pubsubhubbub.appspot.com/"></atom10:link>
          <feedburner:emailServiceId>GomoloPhoto</feedburner:emailServiceId>
          <feedburner:feedburnerHostname>http://feedburner.google.com</feedburner:feedburnerHostname>
          <item>
                 <guid isPermaLink="false">809390</guid>
                 <link>http://feedproxy.google.com/~r/GomoloPhoto/~3/dUyLtllEQUA/photos-rituparna-sengupta-at-the-first-look-launch-of-bengali-movie-a-political-murder</link>
                 <title></title>
                 <description>
Rituparna Sengupta at the first look launch of Bengali movie 'A Political Murder'</description>
                     <a10:updated>6/4/2013 9:55:00 AM</a10:updated>
                     <feedburner:origLink>http://www.gomolo.com/809390/photos-rituparna-sengupta-at-the-first-look-launch-of-bengali-movie-a-political-murder</feedburner:origLink>
                 </item>
              <item>
                     <guid isPermaLink="false">809483</guid>
                     <link>http://feedproxy.google.com/~r/GomoloPhoto/~3/arNMUvINuok/photos-will-smith-jaden-smith-bruce-willis-at-the-premiere-of-hollywood-movie-after-earth</link>
                     <title></title>
                     <description>
Will Smith, Jaden Smith & Bruce Willis at the premiere of Hollywood movie 'After Earth'</description>
                     <a10:updated>6/4/2013 9:53:00 AM</a10:updated>
                     <feedburner:origLink>http://www.gomolo.com/809483/photos-will-smith-jaden-smith-bruce-willis-at-the-premiere-of-hollywood-movie-after-earth</feedburner:origLink>
                 </item>

我正在尝试这个

NSMutableData *data=[[NSMutableData alloc]initWithContentsOfURL:[NSURL URLWithString:@"http://feeds.feedburner.com/GomoloPhoto"]];
GDataXMLDocument *doc=[[GDataXMLDocument alloc]initWithData:data options:0 error:nil];

//specify path
NSArray *links=[doc nodesForXPath:@"//channel/item/description" error:nil];

//load xml data
for (GDataXMLElement *link in links ) {
    NSURL *url=[NSURL URLWithString: link.stringValue];
    [array addObject:url];
}
NSLog(@"array %@",[array objectAtIndex:0]);
NSData *data1=[NSData dataWithContentsOfURL:[array objectAtIndex:0]];
_hotPicsImageView1.image=[UIImage imageWithData:data1];
NSData *data2=[NSData dataWithContentsOfURL:[array objectAtIndex:1]];
_hotPicsImageView2.image=[UIImage imageWithData:data2];
NSData *data3=[NSData dataWithContentsOfURL:[array objectAtIndex:2]];
_hotPicsImageView3.image=[UIImage imageWithData:data3];

但由于某种原因， ImageView 从我的默认图像变为空白，如果您检查<description>标签你会发现它包含图像和一些文本。我如何访问图像文件？有人可以建议我正确的方法吗？

请检查此url在任何在线 xml 查看器中

Answer 1

测试 XPath 的好工具 http://www.xpathtester.com/

你link

也许这对你有帮助 - Parse <img> tag that lies within the <description></description> of an rss2 feed item

NSMutableData *data=[[NSMutableData alloc]initWithContentsOfURL:[NSURL URLWithString:@"http://feeds.feedburner.com/GomoloPhoto"]];
    GDataXMLDocument *doc=[[GDataXMLDocument alloc]initWithData:data options:0 error:nil];

    //specify path
    NSArray *links=[doc nodesForXPath:@"//channel/item/description" error:nil];

    NSMutableArray *array = [NSMutableArray array];

    //load xml data
    for (GDataXMLElement *link in links ) {

        NSString *descWithLink = [link stringValue];

        NSMutableArray *substrings = [NSMutableArray array];

        NSScanner *scanner = [NSScanner scannerWithString:descWithLink];
        [scanner scanUpToString:@"src=" intoString:nil]; 
        while(![scanner isAtEnd]) {
            NSString *substring = nil;
            [scanner scanString:@"src" intoString:nil]; 
            if([scanner scanUpToString:@"\" " intoString:&substring]) {
                [substrings addObject:[substring substringFromIndex:2]];
            }
            [scanner scanUpToString:@"src=" intoString:nil]; 
        }

        NSURL *url=[NSURL URLWithString: substrings[0]];
        [array addObject:url];
    }
    NSLog(@"array %@",[array objectAtIndex:0]);