Memory Leak In line of code - iphone

Question

My app is working fine, but when I run instrument for checking for leaks, it shows me a leak at this line of code, in purple with a 100.0% mark:
xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:url];
Here's the method containing this line:
-(NSString*) languageSelectedStringForKey:(NSString*) key
{
NSString *path = [[NSBundle mainBundle] pathForResource:#"zh" ofType:#"lproj"];
if(selectedLanguage==French)
{
FinalString = [[NSString alloc] initWithFormat:#"http://www.xyz.com/api_com.php?page_id=%d",IDValue];
url = [[NSURL alloc] initWithString:FinalString];
}
else if(selectedLanguage==German)
{
FinalString = [[NSString alloc] initWithFormat:#"http://www.x.com/api_com.php?page_id=%d",IDValue];
url = [[NSURL alloc] initWithString:FinalString];
}
else if(selectedLanguage==Nepali)
{
FinalString = [[NSString alloc] initWithFormat:#"http://www.xy.com/api_com.php?page_id=%d",IDValue];
url = [[NSURL alloc] initWithString:FinalString];
}
xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:url];
[url release];
//Initialize the delegate.
parser = [[NewsParser alloc] initXMLParser];
//Set delegate
[xmlParser setDelegate:parser];
//Start parsing the XML file.
BOOL success = [xmlParser parse];
if(success)
NSLog(#"No Errors");
else
NSLog(#"Error Error Error!!!");
NSBundle* languageBundle = [NSBundle bundleWithPath:path];
NSString* str=[languageBundle localizedStringForKey:key value:#"" table:nil];
return str;
}
Here's my ViewDidLoad method from which languageSelectedStringForKey is called.
- (void)viewDidLoad
{
// Do any additional setup after loading the view from its nib.
appDelegate = (ProgAppDelegate *)[[UIApplication sharedApplication] delegate];
IDValue = 1;
textLabel.text=[self languageSelectedStringForKey:#"Welcome to Advance Localization"];
[super viewDidLoad];
}
What is causing this leak, and how can I fix it?
this is dealloc method:-
- (void)dealloc
{
[xmlParser release];
[parser release];
[nibLoadedCell release];
[super dealloc];
}

Answer 1

Do you ever call
[xmlParser release];
?
If not, you should release it when you no longer need it. Perhaps in the dealloc method of the same class in which that line appears.

Answer 2

You need to make NewsParser parser an instance variable and release it in the dealloc. Above, you init it, but you don't release it. Of course, you can't because it's a delegate of xmlParser. So, to make sure the object is retained, then properly released, it must be an ivar.

Answer 3

You never release FinalString (at least not in the code you posted)
this is held in the URL, which is held by the parser :)
Also, have you considered what would happen if this function is called twice?
Each time you say
xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:url];
you would leak the previous xmlParser ;)
If you are allocating to an instance variable, you have to remember to release the previous object i.e.
[xmlParser release];
xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:url];