How to reload UIViewController

Question

I want to reload all the views contained in tabbar controller(UIViewController).After searching I found that I've to apply setNeedsDisplay Method but I am not able to get where should I apply it.Any other alternatives are also welcomed

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

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    [self customToolbar];
    [self.window addSubview:tabBarController.view];
    [self.window makeKeyAndVisible];    
    return YES;
}
-(void)customToolbar
{
    //Declared view controllers and their Navigation Controller
    .....

    //Declared tab bar items
    .....    

    tabBarController = [[GTabBar alloc] initWithTabViewControllers:viewControllersArray tabItems:tabItemsArray initialTab:1];
}

Solution

The correct way to do this would be to add any VC that needs to be refreshed as an observer to a certain NSNotificationCenter notification name. Once the VC gets this message, just call a selector that calls [self setNeedsDisplay].

To add a VC to NSNotificationCenter:

[[NSNotificationCenter defaultCenter] addObserver:self selector: @selector(setNeedsDisplay) name:@"ViewControllerShouldReloadNotification" object:nil];

Don't forget to call removeObserver:self when the view controller is deallocated.

Comments

[Gajendra K Chauhan]

Hi Stavash..Where can I put this method? I mean "ViewWillAppear"? I am calling view cart web service when I switch tabbar. I am using UIViewController class.

[Stavash]

ViewWillAppear is called for every single time the view is about to be displayed - this is not only when you switch between tab bars, but also when you push and pop a controller from the navigation stack or present and dismiss a modal view. If that suits your needs then yes, otherwise you'll need to think of something else