How to pass tab index value from UITabBarController to UIViewController - ios

Question

I've created tab bar items in the first controller
UITabBarController *tabBarController = [[UITabBarController alloc] init];
tabBarController.delegate = self;
tabBarController.view.frame = CGRectMake(0, 0, 320, 460);
StageViewController *stageViewRegular = [[StageViewController alloc] init];
[stageViewRegular setTitle:#"Regular"];
stageViewRegular.tabBarItem.tag = 1;
StageViewController *stageViewAdvanced = [[StageViewController alloc] init];
[stageViewAdvanced setTitle:#"Advanced"];
stageViewAdvanced.tabBarItem.tag = 2;
NSArray* controllersArray = [NSArray arrayWithObjects:stageViewRegular, stageViewAdvanced, nil];
tabBarController.viewControllers = controllersArray;
tabBarController.selectedIndex = 0;
[self.view addSubview:tabBarController.view];
and I want to pass tabBarItem.tag to the controllers as mentioned above
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
chooseLevel = viewController.tabBarItem.tag;
}
but in the second controller
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
NSLog(#"%d", chooseLevel);
}
the chooseLevel always record old value. If I press the first tab and then press the second tab, the value in chooseLevel is 1 rather than 2.
Does anyone know how to solve it?

Answer 1

Do the following steps :
AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
UIViewController *viewController1 = [[[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil] autorelease];
viewController1.tabBarItem.tag = 0;
UIViewController *viewController2 = [[[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil] autorelease];
viewController2.tabBarItem.tag = 1;
self.tabBarController = [[[UITabBarController alloc] init] autorelease];
self.tabBarController.viewControllers = #[viewController1, viewController2];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
return YES;
}
FirstViewController.m
-(void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
NSLog(#"%d",self.tabBarItem.tag);
}
SecondViewController.m
-(void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
NSLog(#"%d",self.tabBarItem.tag);
}
OutPut :
2013-06-27 18:13:03.913 sampletabs[3981:c07] 0
2013-06-27 18:13:05.282 sampletabs[3981:c07] 1
Thanks, Do let me know it works for you ?

Answer 2

Why don't you use selectedIndex property of the UITabBarController. I think it has the value you are trying to use.
http://developer.apple.com/library/ios/#documentation/uikit/reference/UITabBarController_Class/Reference/Reference.html

Answer 3

You can use selected index property like this:
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
chooseLevel = tabBarController.selected index;
}

Answer 4

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
int selectedtag=self.tabBarController.selectedIndex;
NSLog(#"%d", selectedtag);
}

Answer 5

Do this :
RootViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UITabBarController *tabBarController = [[UITabBarController alloc] init];
tabBarController.delegate = self;
tabBarController.view.frame = CGRectMake(0, 0, 320, 460);
FirstViewController *stageViewRegular = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil];
[stageViewRegular setTitle:#"First"];
stageViewRegular.tabBarItem.tag = 1;
SecondViewController *stageViewAdvanced = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
[stageViewAdvanced setTitle:#"Second"];
stageViewAdvanced.tabBarItem.tag = 2;
NSArray* controllersArray = [NSArray arrayWithObjects:stageViewRegular, stageViewAdvanced, nil];
tabBarController.viewControllers = controllersArray;
tabBarController.selectedIndex = 0;
[self.view addSubview:tabBarController.view];
}
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
NSLog(#"%d",viewController.tabBarItem.tag);
}
FirstViewController
-(void)viewWillAppear:(BOOL)animated
{
NSLog(#"viewWillAppear %d",self.tabBarItem.tag);
}
SecondViewController
-(void)viewWillAppear:(BOOL)animated
{
NSLog(#"viewWillAppear %d",self.tabBarItem.tag);
}
If you need Global value of selected tab Index, then create readWrite property in AppDelegate and set the value in either RootViewController or First/SecondViewController.you will get global value of ChooseLevel.
Thanks,