Tab bar Controller raising NSInternalInconsistencyException

Question

In my SDK 3.0 core data based app, I have a tab bar controller managing 4 tabs. From time to time, apparently randomly, when I launch the app, it crashes with the following

Answer 1

I've had this problem too. Do you have an outlet to the UITabBar itself (not the UITabBarController) in the nib? When I removed that, I stopped having problems.

Sorry this isn't a 100% reliable explanation, but this workaround cleared the problem up for me.

Answer 2

I've gotten this exception a few times, especially when changing things with localizations. Cleaning the targets and then rebuilding seems to work around the issue.

Answer 3

I quickly wrote the following class and showing/hiding tab views from UITabBarController worked like magic:

TabBarDesigner.h

#import <Foundation/Foundation.h>
@interface TabBarDesigner : NSObject 
{

}

+(void) setTabBarController:(UITabBarController *)tabBarController
                      items:(NSArray *)tabBarItems 
            viewControllers:(NSArray *)viewControllers;

+(void) removeItemsInRange:(NSRange) range;

@end

TabBarDesigner.m

#import "TabBarDesigner.h"

static NSArray *_tabBarItems = NULL;
static NSArray *_viewControllers = NULL;
static UITabBarController *_tabBarController = NULL;

@implementation TabBarDesigner

+(void) setTabBarController:(UITabBarController *)tabBarController
                      items:(NSArray *)tabBarItems 
            viewControllers:(NSArray *)viewControllers
{
    if (tabBarItems && viewControllers && tabBarController)
    {
        if ([tabBarItems count] == [viewControllers count])
        {
            [_tabBarItems release];
            [_viewControllers release];
            _tabBarItems = [tabBarItems copy];
            _viewControllers = [viewControllers copy];
            _tabBarController = tabBarController;
        }
    }
}

+(void) removeItemsInRange:(NSRange) range
{
    if (_tabBarController)
    {
        if ( range.location < ([_tabBarItems count] - 1) )
        {
            if ( (range.length + range.location) < [_tabBarItems count] )
            {
                NSMutableArray *tabBarItems = [_tabBarItems mutableCopy];   
                [tabBarItems removeObjectsInRange:range];
                NSMutableArray *viewControllers = [_viewControllers mutableCopy];
                [viewControllers removeObjectsInRange:range];
                [_tabBarController setViewControllers:viewControllers];
                 NSUInteger i;
                for (i = 0; i< [viewControllers count]; i++) 
                {
                    UIViewController *vC = [viewControllers objectAtIndex:i];
                    vC.tabBarItem.image = [[tabBarItems objectAtIndex:i] image];
                    vC.tabBarItem.title = [[tabBarItems objectAtIndex:i] title];
                    vC.tabBarItem.tag = [[tabBarItems objectAtIndex:i] tag];
                }

                [tabBarItems release];
                [viewControllers release];

            }


        }
    }
}


@end

A sample of how to use this class: In your MyAppDelegate.m

#import "TabBarDesigner.h"
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [TabBarDesigner setTabBarController:_tabBarController
                                  items:[_tabBarController.tabBar items] 
                        viewControllers:[_tabBarController viewControllers]];
    // remove the first 3 tabs
    [TabBarDesigner removeItemsInRange:NSMakeRange(0,3)];
    // show all tabs
    [TabBarDesigner removeItemsInRange:NSMakeRange(0,0)];
    // continue with your code
}

Cheers!