Tab Bar Controller (storyboard template) and AppDelegate

Question

When I create a XCode 4 iPhone template for TabBarController with storyboard, its automaticly configured with a main view controller and everything. But there is no propery for the Tab Bar Controller in the AppDelegate. Can I created an outlet for it, and tryed to link it with my Tab Bar Controller in storyboard but that's not possible. Is there a better way to access the Tab Bar Controller in didFinishLaunchingWithOptions method, as it's already kind of hooked up? What I want is self.currentController = current tab in Tab Bar Controller.

AppDelegate.h:

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

AppDelegate.m:

@interface AppDelegate()

@property (nonatomic, assign) UIViewController<SubViewContainer> *currentController;

@end

@synthesize window = _window
@synthesize currentController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

//I need this piece of code to equal the Tab Bar Controller current tab
self.currentController = ?

return YES;
}

//And I'm gonna use this void for some statements about the Tab Bar Controller tabs:
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:
(UIViewController *)viewController
{
// with some statements
}

Solution 1

Assuming things are set up in your storyboard as expected, this should give you a reference to the tab bar controller in didFinishLaunchingWithOptions::

NSLog(@"Root: %@", self.window.rootViewController);
UITabBarController *tabController = (UITabBarController *)self.window.rootViewController;

Usually, you could get the current controller using...

self.currentController = [tabController selectedViewController];

...but since no controller has been selected at the time this method executes, the best guess of what you want is...

self.currentController = [[tabController viewControllers] objectAtIndex:0];

Solution 2

Use self.window.rootViewController.tabBarController to gain access to that view controller’s tab bar controller.

Comments

[ingenspor]

Ok thanks, so if I want self.currentController = current tab in Tab Bar Controller, any suggestion for how to do so?

[Phillip Mills]

Once you have the tab bar controller, you can get its selectedViewController property. Is that what you're asking?

[ingenspor]

I updated my question so it's more clearly. I'm new on this so I don't quite understand how to use you answer in my code but it looks right in the log as it says Root: UITabBarController.

[Phillip Mills]

But self isn't a view controller in this case.

[The Kraken]

I assume you're trying to access the tab bar controller from the App Delegate then. Try the updated code.

[ingenspor]

Yup, that's what I am trying to do. But pasting self.window.rootViewContoller.tabBarController in there isn't working. I took away my tabBarController property/synthesize/delegate code from appdelegate as I'm not supposed to create one. But still I can't reference to my remaining one in the appdelegate, though it says "Root: UITabBarController if i NSLog self.window.rootViewController.

[ingenspor]

Thanks! It getting close, but it says "Incompatible pointer types initializing UITabBarController with an expression of type UIViewController." Maybe I must somehow add the TabBarController as a subview of main window?

[Phillip Mills]

Cast the value you're assigning to get rid of the compiler warning. It's just complaining that you know the type of controller and it doesn't. :-)

[The Kraken]

Looks like @PhillipMills's answer worked out. It looks like a much more elegant solution. I apologize if I was confused with what exactly you were asking. Glad it worked out!