iPhone - difference between GDataXMLNode and GDataXMLElement, and how to use them - iphone

Question

As the google doc is not available anymore, I'm lost with those concepts.
What is a node, and what is an element (that inherits the node) ?
How can I switch from nodes to elements. I mean, for example, if I write :
NSError* error;
NSData* xmlData = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"ForTesting" ofType:#"xml"]];
error = nil;
GDataXMLDocument* XMLDoc = [[[GDataXMLDocument alloc] initWithData:xmlData options:0 error:&error] autorelease];
if (XMLDoc == nil) {
NSLog(#"%#", error.description);
return;
}
GDataXMLNode* xmlElement = [[XMLDoc nodesForXPath:#"//root/fileVersion" error:nil] objectAtIndex:0];
NSString* fileVersion = xmlElement.stringValue;
GDataXMLNode* xmlList = [[XMLDoc nodesForXPath:#"//root/list" error:nil] objectAtIndex:0]; // single item
After that code, how can I write something like that to switch to GDataXMLElement instead of continuing with GDataXMLNode, that would requires me to continue using XPath (I don't want to use it past that point) :
// code don't work : elementsForName is not defined for GDataXMLNode
for (GDataXMLElement* xmlObject in [xmlList elementsForName:#"object"]) {
MyClass* obj = [[[MyClass alloc] initWithXMLElement:xmlObject] autorelease];
}

Answer 1

GDataXMLNode is obviously the classes you use for XML parser- GDataXMLNode.h/.m
In the code you have given returns an array. You can use.
NSArray *myArray = [XMLDoc nodesForXPath:#"//root/fileVersion" error:nil];
You can iterate myArray like this.
for (GDataXMLElement *nodeXmlElt in myArray)
{
//some code
}
Each of my nodeXmlElt will be like given below.
<fileVersion>
<title>San Francisco CBS News</title>
<link>http://news.google.com/news/</link>
<fileVersion>
//getting title
NSArray *elementArray = [nodeXmlElt elementsForName:#"title"];
GDataXMLElement *gdataElement = (GDataXMLElement *)[elementArray objectAtIndex:0];
NSString *title = gdataElement.stringValue; //returns 'San Francisco CBS News'