UITableViewController does not refresh - iphone

Question

I have a tabBar application. In the app delegate i create one NSMutableArray, one UITableViewController and one class (lets say class B) that updates the NSMutableArray.
The tabBar contains
a) The tableViewController which shows the data in the *booksArray
b) Class B which adds data to the booksArray
The tableView works great when it is first loaded. The problem is that when the array updates, not any changes are fired in the UItableViewContoller (when I choose its tab again). Do I have to use delegation? Do I have to change my architecture?
AppDelegate:
visibleBooks = [[NSMutableArray alloc] init];
UINavigationController *navController = [[UINavigationController alloc]
initWithRootViewController:booksTableViewController];
UITabBarController *tabBarController = [[UITabBarController alloc] init];
NSArray *viewControllers = [NSArray arrayWithObjects:navController,qrViewController, nil];
[tabBarController setViewControllers:viewControllers];
In the UITableViewController .h:
#class BookDetailedViewController;
#interface BooksTableViewController : UITableViewController {
NSMutableArray *bookSource;
}
#property (nonatomic,retain) NSMutableArray *bookSource; // IS RETAIN OK?
- (id) initWithDataSource: (NSMutableArray *) source;
#end
In the UITableViewController .m:
- (id) initWithDataSource: (NSMutableArray *) source
{
[super initWithStyle:UITableViewStyleGrouped];
[self setBookSource:source];
[[self navigationItem] setTitle:#"Books"];
return self;
}

Answer 1

You need to invoke [self.tableView reloadData] in UITableViewController each time when your data source is updated, or when you're showing your tableView.
This can be done in viewWillAppear: inside your BooksTableViewController, or in tabBar:didSelectItem: inside UITabBarController.
for example, add this code snippet to BooksTableViewController:
- (void) viewWillAppear:(BOOL) animated
{
[super viewWillAppear:animated];
[self.tableView reloadData];
}