objective c - AppDelegate, rootViewController and presentViewController

Question

I'm doing the Facebook integration tutorial, I want to show my MainViewViewController if the user has a valid token for the current state otherwise I want to show LoginViewController.

MainViewAppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    if (FBSession.activeSession.state == FBSessionStateCreatedTokenLoaded) {
        // To-do, show logged in view
    } else {
        // No, display the login page.
        [self showLoginView];
    }
    return YES;
}
- (void)showLoginView
{
    UIStoryboard *mainstoryboard = [UIStoryboard storyboardWithName:@"MainStoryboard"          bundle:nil];
    LoginViewController* loginViewController = [mainstoryboard      instantiateViewControllerWithIdentifier:@"LoginViewController"];
    [self.window.rootViewController presentViewController:loginViewController animated:YES completion:NULL];
}

Console error :

Warning: Attempt to present <LoginViewController: 0xb492fd0> on <MainViewViewController: 0xb1bd820> whose view is not in the window hierarchy!

I don't want to use a NavigationController.

Answer 1

I had the same issue. Based on the answer to this question, I added [self.window makeKeyAndVisible] just before presentViewController:animated:completion:, and that fixed it for me.

In your case, showLoginView becomes

- (void)showLoginView
{
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    LoginViewController *loginViewController = [storyboard instantiateViewControllerWithIdentifier:@"LoginViewController"];
    [self.window makeKeyAndVisible];
    [self.window.rootViewController presentViewController:loginViewController animated:YES completion:NULL];
}