How to: Save order of tabs when customizing tabs in UITabBarController

Question

I am having problems finding any other information than the docs for how to save the tab order for my UITabBarController, so that the user's customization is saved for next app launch. I have searched online, but have been unable to find any blog posts or articles that goes through the proper code for doing this.

I realize I have to use the delegate methods for the UITabBarController (didEndCustomizingViewControllers:) but I am not sure how I best approach persistance in terms of saving the state of the order the user wants the tabs in.

Can someone post some code, point me in the right direction or perhaps you have a link for something saved? :)

Thanks

Answer 1

First I voted up the previous answer, but then I noticed how ridiculously complex it is. It can and should be simplified.

- (void)applicationDidFinishLaunching:(UIApplication *)application {

    NSArray *initialViewControllers = [NSArray arrayWithArray:self.tabBarController.viewControllers];
    NSArray *tabBarOrder = [[AppDelegate sharedSettingsService] tabBarOrder];
    if (tabBarOrder) {
        NSMutableArray *newViewControllers = [NSMutableArray arrayWithCapacity:initialViewControllers.count];
        for (NSNumber *tabBarNumber in tabBarOrder) {
            NSUInteger tabBarIndex = [tabBarNumber unsignedIntegerValue];
            [newViewControllers addObject:[initialViewControllers objectAtIndex:tabBarIndex]];
        }
        self.tabBarController.viewControllers = newViewControllers;
    }

    NSInteger tabBarSelectedIndex = [[AppDelegate sharedSettingsService] tabBarSelectedIndex];
    if (NSIntegerMax == tabBarSelectedIndex) {
        self.tabBarController.selectedViewController = self.tabBarController.moreNavigationController;
    } else {
        self.tabBarController.selectedIndex = tabBarSelectedIndex;
    }

    /* Add the tab bar controller's current view as a subview of the window. */
    [self.window addSubview:self.tabBarController.view];
}

- (void)applicationWillTerminate:(UIApplication *)application {

    NSInteger tabBarSelectedIndex = self.tabBarController.selectedIndex;
    [[AppDelegate sharedSettingsService] setTabBarSelectedIndex:tabBarSelectedIndex];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

- (void)tabBarController:(UITabBarController *)tabBarController didEndCustomizingViewControllers:(NSArray *)viewControllers changed:(BOOL)changed {

        NSUInteger count = tabBarController.viewControllers.count;
        NSMutableArray *tabOrderArray = [[NSMutableArray alloc] initWithCapacity:count];
        for (UIViewController *viewController in viewControllers) {

            NSInteger tag = viewController.tabBarItem.tag;
            [tabOrderArray addObject:[NSNumber numberWithInteger:tag]];
        }

        [[AppDelegate sharedSettingsService] setTabBarOrder:[NSArray arrayWithArray:tabOrderArray]];
        [tabOrderArray release];
    }

All this happens in AppDelegate. You set UITabBarController's delegate to AppDelegate instance in Interface Builder. sharedSettingsService is what persists the data for me. Basically it can be a NSUserDefaults front-end or anything you like (CoreData for example). So everything is simple, Interface Builder helps here, not makes things more complex.