How can I "reset" the tabbar in an iPhone application -

i've iphone application: when open app see "loginview". if login application see tabbarcontroller. in third , last tab there "logout" button. if click see "loginview" again. problem if login again see "old" tabbar , selected tab third , not one, , there "logout" button. also, if user login different user, see old data of previous user (very dangerous).

here's code: - delegate.h:

uitabbarcontroller *tabbarcontroller; loginviewcontroller *loginview; 

- delegate.m (didfinishlaunchingwithoptions):

[self.window makekeyandvisible];  loginview = [[loginviewcontroller alloc] init];  if (yes) { /* if user not logged */     [self.window addsubview:loginview.view]; } 

delegate.m (methods):

- (void)logincomplete {     [loginview dismissmodalviewcontrolleranimated:yes];     [window addsubview:tabbarcontroller.view]; }  - (void)logoutcomplete {     [[tabbarcontroller view] removefromsuperview];     [tabbarcontroller release];     [window addsubview:loginview.view]; } 

and here's 2 methods in 2 different viewcontrollers:

- (ibaction)login:(id)sender {       tabnavisappdelegate *delegate =       (tabnavisappdelegate *) [[uiapplication sharedapplication] delegate];   [delegate logincomplete];   } 

(the logout method same)

guys, how can solve painful problem? so, here's list of application want: "foursquare", "brightkite" , others. each 1 have login screen, tabbar view , logout button.

thanks @ everyone.

for login-logout-login situations kinds of things need reset @ logout or next login, create notification, "newuserreset." needs reset original state listens notification , runs method whatever kind of resetting needs. tabbar change button title logout, temporary data structures nil/zero/release themselves, etc.

it's nicely decouples logout of things have done you're not trying manipulate view controllers , data storage , view appearances the controller received logout tap.

sending notification easy. when user taps logout button you'll send out notification this:

[[nsnotificationcenter defaultcenter] postnotificationname:@"jmuserlogout"                                                  object:nil]; 

you don't have call jmuserlogout, need string you'll recognize , -- used initials -- ensure don't accidentally send notification has same name notification you're unaware of listening for.

when notification goes out, object has registered defaultcenter listen @"jmuserlogout" perform actions choose. here's how object registers (this should located in place viewwillload or initialization method of object):

[[nsnotificationcenter defaultcenter] addobserver:self                                       selector:@selector(resetfornewuser:)                                          name:@"jmuserlogout"                                        object:nil]; 

the selector there, resetfornewuser:, name of method want run when notification goes out. method looks this:

- (void)resetfornewuser:(nsnotification *)notif {     // here } 

where says // here you'll add code specific app. example, can add tab bar observer of jmuserlogout notification. in resetfornewuser: method you'd change name of logout button login.

in viewcontroller or view or data store holds old data previous user resetfornewuser method delete of data , set things way should fore new user. example, if previous user entered data uitextfield delete text, yourtextfieldname.text = @"";

lastly, it's important remove object observer before it's deallocated. in dealloc method of each object registered receive notification add this:

[[nsnotificationcenter defaultcenter] removeobserver:self]; 

hopefully makes sense. apple documentation nsnotificationcenter explains more , provide several sample apps use notifications.