Question

I have a navigation based iPhone app.
When you press on a cell in the tableview a new UIViewController is pushed to the navigation stack. In this view controller I am setting a custom titleView in the viewDidLoad method:

- (void)viewDidLoad {
    [super viewDidLoad];

    // Setup custom navigation title
    [self setTitle:@"Mediaportal"];
    navItem = [[NavigationBarTitleItemViewController alloc] initWithNibName:@"NavigationBarTitleItem" bundle:nil];
    [navItem setTitle:[theServer name]];
    [navItem setSubTitle:@""];
    [self.navigationItem setTitleView:navItem.view];

…
}

Once I switch back to the RootViewController:

[self.navigationController popToRootViewControllerAnimated:YES];

the app crashes with the following error (NSZombieEnabled=YES):

*** -[CALayer retain]: message sent to deallocated instance 0x5a5fd80

From what I can see the RootViewController still tries to access the custom titleView, which was deallocated with the second view controller. Once I comment out the custom titleView part in my code the app works.
I tried to set the navigationItem.titleView to nil (as found in the apple docs) before the second ViewController is deallocated, but that doesn’t help.

Do you have a hint what I can do to prevent this crash?

Thanks,
Mark.

Answer 1

I finally found the solution for it (a quite simple one).
I have to alloc and init the navItem through its property then it is being retained:

self.navItem = [[NavigationBarTitleItemViewController alloc] initWithNibName:@"NavigationBarTitleItem" bundle:nil];