Need help fixing iPhone memory leaks!

Question

I encountered some strange memory leaks executing following code on iPhone device:

@implementation TestViewController
@synthesize myButton;

- (IBAction)buttonPressed {
    ABPeoplePickerNavigationController* selectContactViewController = nil;

    selectContactViewController = [[ABPeoplePickerNavigationController alloc] init];
    selectContactViewController.peoplePickerDelegate = self;
    [self presentModalViewController:selectContactViewController animated:YES];
    [selectContactViewController release];
}  

Releasing the picker simple done as follows:

- (void)peoplePickerNavigationControllerDidCancel:(ABPeoplePickerNavigationController *)peoplePicker {

    [self dismissModalViewControllerAnimated:YES];
}

Instruments marks "selectContactViewController = [[ABPeoplePickerNavigationController alloc] init];" as leaking. Any idea why?

Answer 1

You might want to construct your Picker control like so:

ABPeoplePickerNavigationController* selectContactViewController = nil;

selectContactViewController = [[[ABPeoplePickerNavigationController alloc] init] autorelease];
selectContactViewController.peoplePickerDelegate = self;
[self presentModalViewController:selectContactViewController animated:YES];

When you present the modal view controller, it will retain the view on its own. That's how it's able to still pass you an instance of the view controller to your delegate. Best bet is to set the view controller to be autoreleased, so when it gets popped from the navigation controller, the NSAutoReleasePool will garbage collect it.

Answer 2

Just a comment - do you use any protocol like UINavigationControllerDelegate in the interface declaration?

I encountered a situation where just referencing this protocol caused a similar leak message.