CODEWITHSUNDEEP
objective-ciosmemory-management
JamesB41
JamesB41

Reputation: 703

Releasing Main View Controller (iOS)

I've searched for this on Apple's site and can only seem to find documentation using Storyboards or Navigation Controllers, neither of which I'm using. It's an incredibly straightforward question about memory management.

I created a completely blank application. In my AppDelegate's didFinishLaunchingWithOptions function I'm creating an instance of a View Controller which I've built. My design (which itself could be a problem) is to have a 1:1 relationship between View Controllers and Views.

So the main menu of my application, which is a launching pad for everything is in MenuViewController.h/m.

In .h:

MenuViewController *m;

In .m:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];

    m = (MenuViewController *)[[MenuViewController alloc] init];
    m.window = self.window;
    [m doStuff]; // handful of functions, not actually called this
    //[m release]; // doesn't make sense to me
    return YES;
}

This is where I'm confused. I want this to exist for basically the entirety of the application life cycle. But I'm also under the impression that you should (in the scope of the current function) release anything you allocate. If you need it beyond that, you should retain it elsewhere first. Is this not true?

My fundamental question is...where should I be releasing this View Controller? Is there anything else I've said that seems out of whack?

Upvotes: 0

Views: 357

Answers (2)

DrummerB
DrummerB

Reputation: 40211

You're right. Generally you should release anything you create in a scope. But in this case you want ownership of the view controller. In this case you need to release the object in the dealloc method of your app delegate:

- (void)dealloc {
    [m release];
    [super dealloc];
}

Alternatively you could define a @property for your view controller with retain flag and then do this:

MenuViewController *viewController = [[MenuViewController alloc] init];
self.m = viewController;
[viewController release];

Btw, you don't need to cast to MenuViewController in either case.

EDIT: I completely missed that you don't add your view controller to your window. Good point @Eimantas.

Upvotes: 0

Eimantas
Eimantas

Reputation: 49354

The initialization is wrong. You don't assign a window to controller, you assign a controller to window:

    // window creation code here
    ...
    m = [[MenuViewController alloc] init];
    [window setRootViewController:m]; // window does retain for m
    [m release]; // so we release it here
    [self.window makeKeyAndVisible];
    return YES
}

Upvotes: 2

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