無法使用touchXML，nodesForXPath返回任何

Question

我試圖使用touchXML庫解析XML，但沒有得到結果解析XML，代碼如下

NSError *error = nil;  
CXMLDocument *xmlParser = [[CXMLDocument alloc] initWithXMLString:dataString options:0 error:&error]; 

NSArray *resultNodes = NULL; 
resultNodes = [xmlParser nodesForXPath:@"//entry" error:&error]; 

for (CXMLElement *resultElement in resultNodes) { 
    NSMutableDictionary *blogItem = [[NSMutableDictionary alloc] init]; 

    int counter; 

    for(counter = 0; counter < [resultElement childCount]; counter++) { 
     [blogItem setObject:[[resultElement childAtIndex:counter] stringValue] forKey:[[resultElement childAtIndex:counter] name]]; 
    }   
} 

方法nodesForXPath：不返回任何東西將resultNodes數組留給0個對象。我在dataString中獲得正確的xml，並且CXMLDocument也正在準備好。我試過調試它，但我沒有看到接受resultNodes中的0對象，NSError也沒有包含任何內容（即沒有發生錯誤）。我想解析的xml文件如下所示。

<feed xmlns:s="http://syndication.nhschoices.nhs.uk/services" xmlns="http://www.w3.org/2005/Atom"> 
<title type="text">...</title> 
<id>...</id> 
<rights type="text">© Crown Copyright 2009</rights> 
<updated>2012-04-27T11:33:02+01:00</updated> 
<category term="Search"/> 
<logo>...</logo> 
<author>...</author> 
<s:SearchCoords>174900,517900</s:SearchCoords> 
<entry> 
    <id> 
     http://v1.syndication.nhschoices.nhs.uk/organisations/gppractices/32248 
    </id> 
    <title type="text">Sayer A</title> 
    <updated>2012-04-27T10:33:02Z</updated> 
    <link rel="self" title="Sayer A" href="http://v1.syndication.nhschoices.nhs.uk/organisations/gppractices/32248?apikey=YAHUGHET"/> 
    <link rel="alternate" title="Sayer A" href="http://www.nhs.uk/ServiceDirectories/Pages/GP.aspx?pid=15F37AEF-EC5B-4A90-9E72-269ADEB39629"/> 
    <content type="application/xml"> 
     <s:organisationSummary> 
      <s:name>Sayer A</s:name> 
      <s:address> 
       <s:addressLine>The Richmond Green Medical Cen</s:addressLine> 
       <s:addressLine>19 The Green</s:addressLine> 
       <s:addressLine>Richmond</s:addressLine> 
       <s:addressLine>Surrey</s:addressLine> 
       <s:postcode>TW91PX</s:postcode> 
      </s:address> 
      <s:contact type="General"> 
       <s:telephone>020 83327515</s:telephone> 
      </s:contact> 
      <s:geographicCoordinates> 
       <s:northing>174900</s:northing> 
       <s:easting>517800</s:easting> 
       <s:longitude>-0.305512266736965</s:longitude> 
       <s:latitude>51.4608026642546</s:latitude> 
      </s:geographicCoordinates> 
      <s:Distance>0.1</s:Distance> 
     </s:organisationSummary> 
    </content> 
</entry> 
<entry> 
    <id> 
     http://v1.syndication.nhschoices.nhs.uk/organisations/gppractices/33420 
    </id> 
    <title type="text">Griffiths W</title> 
    <updated>2012-04-27T10:33:02Z</updated> 
    <link rel="self" title="Griffiths W" href="http://v1.syndication.nhschoices.nhs.uk/organisations/gppractices/33420?apikey=YAHUGHET"/> 
    <link rel="alternate" title="Griffiths W" href="http://www.nhs.uk/ServiceDirectories/Pages/GP.aspx?pid=EEC98A8A-B888-4F44-A0B6-DC6ABCBF19CE"/> 
    <content type="application/xml"> 
     <s:organisationSummary> 
      <s:name>Griffiths W</s:name> 
      <s:address> 
       <s:addressLine>Paradise Road Surgery</s:addressLine> 
       <s:addressLine>37 Paradise Road</s:addressLine> 
       <s:addressLine>Richmond</s:addressLine> 
       <s:addressLine>Surrey</s:addressLine> 
       <s:postcode>TW91SA</s:postcode> 
      </s:address> 
      <s:contact type="General"> 
       <s:telephone>020 89402423</s:telephone> 
      </s:contact> 
      <s:geographicCoordinates> 
       <s:northing>174800</s:northing> 
       <s:easting>518100</s:easting> 
       <s:longitude>-0.301388352909701</s:longitude> 
       <s:latitude>51.4601120315006</s:latitude> 
      </s:geographicCoordinates> 
      <s:Distance>0.223606797749979</s:Distance> 
     </s:organisationSummary> 
    </content> 
</entry> 
<entry> 
    <id> 
     http://v1.syndication.nhschoices.nhs.uk/organisations/gppractices/33035 
    </id> 
    <title type="text">Dr Da Costa</title> 
    <updated>2012-04-27T10:33:02Z</updated> 
    <link rel="self" title="Dr Da Costa" href="http://v1.syndication.nhschoices.nhs.uk/organisations/gppractices/33035?apikey=YAHUGHET"/> 
    <link rel="alternate" title="Dr Da Costa" href="http://www.nhs.uk/ServiceDirectories/Pages/GP.aspx?pid=EDCE215D-6412-4AAB-AFC4-9F37888D413C"/> 
    <content type="application/xml"> 
     <s:organisationSummary> 
      <s:name>Dr Da Costa</s:name> 
      <s:address> 
       <s:addressLine>The Vineyard Surgery</s:addressLine> 
       <s:addressLine>35 The Vineyard</s:addressLine> 
       <s:addressLine>Richmond</s:addressLine> 
       <s:addressLine>Surrey</s:addressLine> 
       <s:postcode>TW106PP</s:postcode> 
      </s:address> 
      <s:contact type="General"> 
       <s:telephone>020 89480404</s:telephone> 
      </s:contact> 
      <s:geographicCoordinates> 
       <s:northing>174600</s:northing> 
       <s:easting>518100</s:easting> 
       <s:longitude>-0.301044685875553</s:longitude> 
       <s:latitude>51.4581333717098</s:latitude> 
      </s:geographicCoordinates> 
      <s:Distance>0.360555127546399</s:Distance> 
     </s:organisationSummary> 
    </content> 
</entry> 

Answer 1

我從來沒有與touchXML的工作，但它可能是你需要設置你的命名空間，喜歡這裏：Getting the value of an Element in Cocoa using TouchXML

Answer 2

只是檢查出這一點，我能夠解析類似樣的反應：

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    self.rqst=[[WebRqst alloc] init]; 
    [self.rqst startLoading:[NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"PASS UR URL"]] 
         vCtr:self]; 
} 

**// a method to grab the attributes.** 
- (void)parseAttributesForElement:(CXMLElement*)element andDictionary:(NSMutableDictionary*)dictionary { 
    NSString *strName,*strValue;  
    NSArray *arAttributes = [(CXMLElement*)element attributes]; 
    for (int i=0; i<arAttributes.count; i++) { 
     strName = [[arAttributes objectAtIndex:i] name]; 
     strValue = [[arAttributes objectAtIndex:i] stringValue]; 
     if(strName && strValue && [strName length]>0 && [strValue length]>0) { 
      [dictionary setValue:strValue forKey:strName]; 
     } 
    } 
} 

**// a method to parse the node & store in dictionary** 
- (void)parseThisNode:(CXMLNode*)node storeInDictionary:(NSMutableDictionary*)dOfNode { 
    NSString *strName = [node name]; 
    NSString *strValue = [node stringValue]; 
    if(strName && [strName length]>0 && ![strName isEqualToString:@"text"]) { 

     NSMutableDictionary *dOfAttributes = [NSMutableDictionary dictionary]; 

     // if node has value 
     if(strValue && [strValue length]>0) { 
      [dOfAttributes setValue:strValue forKey:@"value"]; 
     } 

     // if node has attributes 
     if([node isKindOfClass:[CXMLElement class]] && [(CXMLElement*)node attributes].count>0) { 
      [self parseAttributesForElement:(CXMLElement*)node andDictionary:dOfAttributes]; 
     } 

     // if node has childs 
     NSArray *arChildern = [node children]; 
     if(arChildern.count>0) { 
      NSMutableDictionary *dOfTAG=[NSMutableDictionary dictionary]; 
      for (CXMLNode *nodeChildChild in arChildern) { 
       // recursive call of a function 
       [self parseThisNode:nodeChildChild storeInDictionary:dOfTAG]; 
      } 
      if([[dOfTAG allKeys] count]>0) [dOfAttributes setValue:dOfTAG forKey:@"child"]; 
     } 

     id valueFK = [dOfNode valueForKey:strName]; 
     // verify if same node is repeated, add it to array (e.g. link tag is repeated) 
     if([valueFK isKindOfClass:[NSMutableArray class]]) { 
      NSMutableArray *ar=(NSMutableArray*)valueFK; 
      [ar addObject:dOfAttributes]; 
      [dOfNode setValue:ar forKey:strName]; 
     } else if([valueFK isKindOfClass:[NSMutableDictionary class]]) { 
      NSMutableArray *ar=[NSMutableArray arrayWithObjects:valueFK,dOfAttributes, nil]; 
      [dOfNode setValue:ar forKey:strName]; 
     } else { 
      [dOfNode setValue:dOfAttributes forKey:strName]; 
     } 
    } 
} 

**// pass the data to this method & it will return a dictionary** 
- (NSDictionary *)startParsingUsingData:(NSData *) data { 
    // create a mutable-empty dictionary wich will hold the data 
    NSMutableDictionary *dictionaryParsed = [NSMutableDictionary dictionary]; 

    // verify - do we have proper data for parsing or not 
    if(data && [data length]>0) { 
     // load a data into XML Document 
     CXMLDocument *doc = [[CXMLDocument alloc] initWithData:data options:0 error:nil]; 

     // grab all the tags of XML 
     NSArray *nodes = [doc nodesForXPath:@"*" error:nil]; 

     // start a loop to goThrough each tag of xml 
     for (CXMLNode *nodeFeed in nodes) { 

      // verify that you reached to desired tag or not 
      if([[nodeFeed name] isEqualToString:@"feed"]) { 
       // just write this code to get data parsed & stored in our dictionary 
       [self parseThisNode:nodeFeed storeInDictionary:dictionaryParsed]; 

       // grab the childrens of tag (as per requirement) 
       dictionaryParsed=[[dictionaryParsed valueForKey:@"feed"] valueForKey:@"child"]; 
      } 
     } 
    } 

    // return the dictionary. 
    if([[dictionaryParsed allKeys]count]>0) { 
     return [NSDictionary dictionaryWithDictionary:dictionaryParsed]; 
    } else { 
     return nil; 
    } 
} 

// It's my delegate method where I am getting my NSData 
    - (void)webRequestReceivedData:(NSData *)data { 
     if(data && [data length]>0) { 
      NSLog(@"Details are as follows\n%@", 
        [self startParsingUsingData:data]); //This is the method required which will parse the data 
     } 
    } 

希望，現在你就可以分析數據。