UI is not updating while sending data from another view controller on UITabBar? - iphone

Question

i am using UITabBar to display two viewControllers, firstViewController is a uiview and secondViewController is a table view. what my need is when i clicked the second view table cell, the value should be updated on UILabel of firstViewController.
my code is here,
In secondviewcontroller.h
#interface firstviewcontroller {
NSMutableArray *stationnamestobepassed;
}
#property (nonatomic, retain) NSMutableArray *stationnamestobepassed;
#end
In secondviewcontroller.m declare this
#implementation firstviewcontroller
#synthesize stationnamestobepassed;
-(void) someaction{
stationnamestobepassed = [NSMutableArray
arrayWithObjects:#"string1",#"string2",#"string3"];
secondviewcontroller = [[secondviewcontroller alloc]initWithNibName:#"NIbName"
Bundle:nil];
secondviewcontroller.stationnamespassed = self.stationnamestobepassed;
//i am not pushing the view controller.
}
#end
In firstviewcontroller.h declare this
#interface secondviewcontroller {
NSMutableArray *stationnamespassed;
}
#property (nonatomic, retain) NSMutableArray *stationnamespassed;
#end
In firstviewcontroller.m declare this
#implementation secondviewcontroller
#synthesize stationnamespassed;
-(void)viewWillAppear:(BOOL)animated
{
//stationNameDisplay is a uilabel
stationNameDisplay.text=[stationnamespassed objectAtIndex:0];
NSLog(#"station name %#",[stationnamespassed objectAtIndex:0]);
}
-(void) dealloc{
[stationnamespassed release];
[super release];
}
#end
problem is , value is not updating and it gives NULL. but i tried with pushing the first vie and it works. actually i don't want to push that view controller because i was already exist on tab.

Answer 1

your view will appear called out when you select the tab. while this line makes a new object of that controller, not that of tab controller.
secondviewcontroller = [[secondviewcontroller alloc]initWithNibName:#"NIbName"
Bundle:nil];
to do what you want. you will have to do some thing like this
UINavigationController* navController = [[self.tabBarController viewControllers] objectAtIndex:/*your tab index on which desiredControllerResides*/];
NSArray* viewControllers= [navController viewControllers];
for(UIViewController *theController in viewControllers)
{
if([theController isKindOfClass:[secondviewcontroller]])
{
theController.stationnamespassed = self.stationnamestobepassed;
//i.e this line of your code secondviewcontroller.stationnamespassed = self.stationnamestobepassed;
}
}