XML file parsing delegate issues - ios

Question

i have xml file to which i'm parsing through the delegates method of NSXML parser. I have three delegates method didStart , FoundCharacters and didEndElement. When i parse the file and when it goes in found characters method it shows me all the string data from xml file in console, but i'm trying to take only the given tag data value. Its showing me all the string data from xml file . My xml file is this,
<?xml version="1.0" encoding="UTF-8"?>
<QF id="AB2001" topic="Alertness" category="C&M" ni_exempt="no">
<question>
<xref>DES s4, DES s9, HC r159-161</xref>
<text>Before you make a U-turn in the road, you should</text>
<graphic></graphic>
<prompt>Mark one answer</prompt>
<voice id="AB2001-1"/>
<explanation>
<text>If you want to make a U-turn, slow down and ensure that the road is clear in both directions. Make sure that the road is wide enough to carry out the manoeuvre safely.</text>
<voice id="AB2001-2"/>
</explanation>
</question>
<answers>
<answer correct="no">
<text>give an arm signal as well as using your indicators</text>
<graphic></graphic>
</answer>
<answer correct="no">
<text>signal so that other drivers can slow down for you</text>
<graphic></graphic>
</answer>
<answer correct="yes">
<text>look over your shoulder for a final check</text>
<graphic></graphic>
</answer>
<answer correct="no">
<text>select a higher gear than normal</text>
<graphic></graphic>
</answer>
</answers>
The methods are these through which i'm parsing,
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *) namespaceURI qualifiedName:(NSString *)qName
attributes: (NSDictionary *)attributeDict
{
if([elementName isEqualToString:#"QF"]) {
NSLog(#"ID %#",[attributeDict objectForKey:#"id"]);
NSLog(#"Topic %#",[attributeDict objectForKey:#"topic"]);
}
if( [elementName isEqualToString:#"question"])
{
_foundValue = [[NSMutableString alloc] init];
}
}
-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
// Store the found characters if only we're interested in the current element.
if([_currentElement isEqualToString:#"xref"]){
// init the ad hoc string with the value
_currentElement = [[NSMutableString alloc] initWithString:string];
NSLog(#"Hello");
} else {
// append value to the ad hoc string
[_currentElement stringByAppendingString:string];
NSLog(#"Hi");
}
NSLog(#"Processing value for : %#", string);
}
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if( [elementName isEqualToString:#"QF"])
{
[_foundValue setString:elementName];
NSLog(#"rr %#",_foundValue);
}
if( [elementName isEqualToString:#"xref"])
{
[_foundValue setString:elementName];
}
_currentElement = nil;
}
In console i'm getting all the string data, from and even from answer tag but i haven't given that tag to parse. I'm confused that why it isn't getting value from the tag which i have given?

Answer 1

If I am understanding correctly what you want (to get xref element's value), first declare a NSMutableString* tmpString to which you will append xref's value in foundCharacters method. Then this should do it:
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *) namespaceURI qualifiedName:(NSString *)qName attributes: (NSDictionary *)attributeDict
{
_currentElement = [[NSMutableString alloc]initWithString:elementName];
if([elementName isEqualToString:#"QF"]) {
NSLog(#"ID %#",[attributeDict objectForKey:#"id"]);
NSLog(#"Topic %#",[attributeDict objectForKey:#"topic"]);
}
if( [elementName isEqualToString:#"xref"])
{
_tmpString = [[NSMutableString alloc] init];
}
}
-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
if([_currentElement isEqualToString:#"xref"]){
[_tmpString appendString:string];
}
}
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if( [elementName isEqualToString:#"QF"])
{
[_foundValue setString:elementName];
}
if( [elementName isEqualToString:#"xref"])
{
NSLog(#"xref %#",_tmpString);
[_foundValue setString:elementName];
}
_currentElement = nil;
}
Output is:
ID AB2001
Topic Alertness
xref DES s4, DES s9, HC r159-161
FoundCharacters method is one capturing text between start and end tag of an element. So we keep track of current element, and if it is element we are interested in, we get its text inside foundCharacters method.