如何从雅虎天气预报XML文档中获取图片网址？

Question

我从yahoo weather获取天气信息，我可以从文档解析温度信息，但有问题请我不能说我使用NSXMLParser从<escription>元素获取图像的URL即

<description> 
<![CDATA[ 
<img src="http://l.yimg.com/a/i/us/we/52/28.gif"/><br /> <b>Current Conditions:</b><br /> Mostly Cloudy, 61 F<BR /> <BR /><b>Forecast:</b><BR /> Thu - Showers. High: 66 Low: 48<br /> Fri - AM Light Rain. High: 52 Low: 37<br /> Sat - Partly Cloudy. High: 61 Low: 47<br /> Sun - AM Clouds/PM Sun. High 
]]> 
<![CDATA[ 
: 66 Low: 48<br /> Mon - PM Showers. High: 62 Low: 50<br /> <br /> <a href="http://us.rd.yahoo.com/dailynews/rss/weather/Hakuba_Station__JP/*http://weather.yahoo.com/forecast/JAXX0105_f.html">Full Forecast at Yahoo! Weather</a><BR/><BR/> (provided by <a href="http://www.weather.com" >The Weather Channel</a>)<br/> 
]]> 
</description> 

用于解析MXL文件。

Answer 1

基于@ haras.prasad回答我解决了使用NSXMLParser委托和NSRegularExpression

- (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock { 
    NSString *cdataString = [[NSString alloc] initWithData:CDATABlock encoding:NSUTF8StringEncoding]; 
    // Do extraction of image src here 
    NSError* error; 
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(<img\\s[\\s\\S]*?src\\s*?=\\s*?['\"](.*?)['\"][\\s\\S]*?>)+?" 
                      options:NSRegularExpressionCaseInsensitive 
                      error:&error]; 

    NSString *imageUrlString = nil; 
    NSTextCheckingResult *match = [regex firstMatchInString:cdataString options:0 range:NSMakeRange(0, [cdataString length])]; 
    if (match) 
    { 
     imageUrlString = [cdataString substringWithRange:[match rangeAtIndex:2]]; 

     self.iconUrl = imageUrlString; 
    } 

} 

Answer 2

你可以得到CDATA字符串：

NSString *prefix = @"<![CDATA["; 
if ([xmlString hasPrefix:prefix]) { 
    NSString *cdataString = [_factString substringWithRange:NSMakeRange((prefix.length+1), xmlString.length - 3 -(prefix.length+1))]; 
    // Do stuff with CDATA here... 
    NSLog(@"%@", cdataString); 
} 

Answer 3

在你NSXMLParserDelegate，你可以调用委托方法foundCDATA和处理数据在那里。

- (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock { 
     NSString *cdataString = [[NSString alloc] initWithData:CDATABlock encoding:NSUTF8StringEncoding]; 
     // Do extraction of image src here 
} 

您可以检查委托方法这里的文档：NSXMLParserDelegate