NSXMLParserDelegate not responding - ios

Question

I am trying to develop an XML parser in objective-C using the method described in http://wiki.cs.unh.edu/wiki/index.php/Parsing_XML_data_with_NSXMLParser.
I have coded up the entire flow but the delegate call back methods just won't respond!
Please take a look at the following code blocks and let me know if you could figure out any mistakes/errors...
Parser is being called from:
NSString* filePath = [[NSBundle mainBundle] pathForResource:#"cache" ofType:#"xml"];
NSLog(#"Path location is : %#",filePath);
NSData* xmlData = [NSData dataWithContentsOfFile:[NSURL URLWithString:filePath]];
NSXMLParser *nsXmlParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlData];
if(nsXmlParser!=NULL)
{
NSLog(#"parser is %#",nsXmlParser);
}
HDDataXML *parser = [[HDDataXML alloc] initXMLParser];
[nsXmlParser setDelegate:parser];
BOOL success = [nsXmlParser parse];
// test the result
if (success)
{
NSLog(#"No errors - effects count : i");
} else
{
NSLog(#"Error parsing document!");
}
All I see here is Error parsing document! The filePath variable is OK and the parser is not null.
Now, in the delegate's .h file:
#import <Foundation/NSObject.h>
#import "EffectsCache.h"
#class EffectsCache;
#interface HDDataXML : NSObject<NSXMLParserDelegate>
{
EffectsCache *effectsHandler;
NSMutableString *currentElementValue;
NSMutableArray *effects;
}
- (void)parser:(NSXMLParser *)parser
didStartElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qualifiedName
attributes:(NSDictionary *)attributeDict;
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string ;
- (void)parser:(NSXMLParser *)parser
didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName;
- (HDDataXML *) initXMLParser;
#property (nonatomic, retain) EffectsCache *effectsHandler;
#property (nonatomic, retain) NSMutableArray *effects;
#end
And in the implementation of the delegate in .m:
#import "HDDataXML.h"
#implementation HDDataXML
#synthesize effects, effectsHandler;
- (HDDataXML *) initXMLParser
{
[super init];
effects = [[NSMutableArray alloc] init];
return self;
}
- (void)parser:(NSXMLParser *)parser
didStartElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qualifiedName
attributes:(NSDictionary *)attributeDict
{
NSLog(#"started parsing");
if ([elementName isEqualToString:#"effects"]) {
NSLog(#"effects element found – create a new instance of EffectsCache class...");
effectsHandler = [[EffectsCache alloc] init];
}
}
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
NSLog(#"mid parsing");
if (!currentElementValue)
{
currentElementValue = [[NSMutableString alloc] initWithString:string];
}
else
{
[currentElementValue appendString:string];
}
NSLog(#"Processing value for : %#", string);
}
- (void)parser:(NSXMLParser *)parser
didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName
{
NSLog(#"done parsing");
if ([elementName isEqualToString:#"effects"])
{
return;
}
if ([elementName isEqualToString:#"effect"])
{
[effectsHandler addObject:effects];
[effectsHandler release];
effectsHandler = nil;
}
else
{
NSLog(#"cuurent value - %#",currentElementValue);
[effects setValue:currentElementValue forKey:elementName];
}
[currentElementValue release];
currentElementValue = nil;
}
Point is, the call back methods are not working.
Please help me find the bug.
Thanks in advance.

Answer 1

nsXmlParser.delegate = self;
[nsXmlParser parse];
and dont forget in the .h file to call the delegate
<NSXMLParserDelegate>

Answer 2

Ok... I solved it, finally:
As suggested by Martin R, I changed the code for calling the delegate:
NSString* filePath = [[NSBundle mainBundle] pathForResource:#"effects_cache" ofType:#"xml"];
NSLog(#"Path location is : %#",filePath);
NSData* xmlData = [NSData dataWithContentsOfFile:filePath];
NSXMLParser *nsXmlParser = [[NSXMLParser alloc] initWithData:xmlData];
Before doing this modification, the xmlData was null.
One other small modification was needed:
change:
[effectsHandler addObject:effects];
TO
[effects setValue:currentElementValue forKey:elementName];