Objective-C Fundamentals

Important protocols
161
Listing 7.13
NSXMLParser methods
- (void)parser:(NSXMLParser *)parser
didEndElement:(NSString *)elementName
namespaceURI:(NSString *)namespaceURI
qualifiedName:(NSString *)qName
{
NSLog(@"Found an element named: %@ with a value of: %@",
elementName, element);
}
This method is called when the parser sees anything between an element’s beginning
and end. You use this entry point as a way to collect all the characters that are between
an XML element beginning and ending: you call the appendString method on the
NSMutableString (listing 7.14). By doing this every time the parser:foundCharacters:
method is called, by the time the parser:didEndElement method is called, the
NSMutableString will be complete. In this method, you first make sure you’ve initialized
your NSMutableString element, and then you append the string you’ve provided,
shown in the next listing.
Listing 7.14
NSXMLParser methods
- (void)parser:(NSXMLParser *)parser
foundCharacters:(NSString *)string
{
if (element == nil)
element = [[NSMutableString alloc] init];
[element appendString:string];
}
Now all that’s left to do is create an instance of your parser and watch it go. Go to
Parser_ProjectAppDelegate.m and add the code shown in the following listing into
the already existing method.
Listing 7.15
Initializing the Parser
- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
}
Parser *parser = [[Parser alloc] init];
return YES;
If you run the application and bring up the terminal window (Shift-Command-R), the
output shown in the following listing should be generated.