second Tab is always greyed out in UITabbarController - ios

Question

I'm trying to embed two NavBar Controllers into a UITabbarController, using the code below in the app delegate:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
[window makeKeyAndVisible];
// Configure and show the window.
FirstViewController *firstController = [[FirstViewController alloc] initWithNibName:nil bundle:NULL];
self.firstNav = [[UINavigationController alloc] initWithRootViewController:firstController];
SecondTableViewController *anotherOne = [[SecondTableViewController alloc] initWithNibName:nil bundle:NULL];
self.anotherNav = [[UINavigationController alloc] initWithRootViewController:anotherOne];
NSArray *twoViewControllers = [[NSArray alloc]initWithObjects:self.anotherNav,self.firstNav, nil];
self.tabBarController = [[UITabBarController alloc]init];
[self.tabBarController setViewControllers:twoViewControllers];
[window addSubview:self.tabBarController.view];
[window setRootViewController:tabBarController];
return YES;
}
The two tabs are displayed fine, with their names, but I can select the first one only, the second one is always greyed out and does not respond to touch events. I reversed the navController assignment into the Tabbar (i.e. in the array twoViewControllers), and each view is displayed fine (in the first tab).
The app delegate does not implement UITabbarDelegate and uiTabBarControllerDelegate. I don't use story boards.
Any obvious reason why the second tab is always greyed out ?
Sample Code:
It's just Apple's Locations tutorial (with ARC)
here
Then change :
(void)applicationDidFinishLaunching:(UIApplication *)application {}
for
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// Configure and show the window.
RootViewController *cont1 = [[RootViewController alloc] initWithNibName:nil bundle:NULL];
RootViewController *cont2 = [[RootViewController alloc] initWithNibName:nil bundle:NULL];
NSManagedObjectContext *context = [self managedObjectContext];
if (!context) {
// Handle the error.
}
cont1.managedObjectContext = context;
cont2.managedObjectContext = context;
UINavigationController *aNav1 = [[UINavigationController alloc] initWithRootViewController:cont1];
UINavigationController *aNav2 = [[UINavigationController alloc] initWithRootViewController:cont2];
NSArray *twoViewControllers = [[NSArray alloc]initWithObjects:aNav1,aNav2, nil];
self.tabBarController = [[UITabBarController alloc]init];
[self.tabBarController setViewControllers:twoViewControllers];
//[window addSubview:[tabBarController view]];
[window setRootViewController:tabBarController];
[window makeKeyAndVisible];
}
and replace #interface LocationAppDelegate ...#end by
#interface LocationsAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UITabBarController *tabBarController;
NSPersistentStoreCoordinator *persistentStoreCoordinator;
NSManagedObjectModel *managedObjectModel;
NSManagedObjectContext *managedObjectContext;
}
#property (nonatomic, strong) IBOutlet UIWindow *window;
#property (nonatomic, strong) UITabBarController *tabBarController;
- (IBAction)saveAction:sender;
#property (nonatomic, strong, readonly) NSManagedObjectModel *managedObjectModel;
#property (nonatomic, strong, readonly) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, strong, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator;
#property (weak, nonatomic, readonly) NSString *applicationDocumentsDirectory;
#end
and Compile and run.

Answer 1

Try to get rid of [window addSubview:self.tabBarController.view];