Application windows are expected to have a root view controller at the end of application launch - even with all known issues fixed

Question

I have this problem, however none of the information I can find on this forum or the internet in general seems to be able to help me.

There seem to be two places where this error can come about:

1. main.m - my function looks like this:

  int main(int argc, char *argv[])
    {
        @autoreleasepool {
            return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
        }
    }

The last argument in UIApplicationMain returns an NSString value of the class of my AppDelegate. This is therefore working fine.

2.AppDelegate.m - there is an "older" way of setting the root view controller which is like this:

  [self.window addSubview:rootViewController];

However, in my app it has already been updated to:

self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];

So none of the current information on the internet works. It is slightly more puzzling as my colleague can get it to work on his computer perfectly fine - he was the one that sent me the app source code so all the settings and code should be exactly the same.

I am trying to launch this in the simulator. It is built against iOS 5, but I'm trying to run it on the iOS 6.0 simulator.

I have the latest XCode (4.5.1).

Is there any reason this would be happening? And how can I rectify it?

Many thanks

Tom

Answer 1

I ran into exactly the same thing trying to add a UITableView to a single-view app. Instead, create a default Master-Detail Application project (file->new->target->...) and see the AppDelegate's implementation of didFinishLaunchingWithOptions:

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

MDMasterViewController *masterViewController = [[MDMasterViewController alloc] initWithNibName:@"MDMasterViewController" bundle:nil];
self.navigationController = [[UINavigationController alloc] initWithRootViewController:masterViewController];
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];
return YES;
}

Rather than directly setting your view controller as the window's rootViewController, you need to create a navigation controller init'ed with your view controller for initWithRootViewController, then set that nav controller as the window's rootViewController. (Notice you also have to squirrel away that nav controller in a property so it doesn't get destructed).

Answer 2

Just change this:

[window addSubview:tabBarController.view];

to this:

[window setRootViewController:tabBarController];

Or whatever was in the addSubView: