I'm trying to create an iPad application with a similar user interface to Apple's Mail application, i.e:

• RootView controller (table view) on the left hand side of the split view for navigation with a multiple view hierarchy. When a table cell is selected a new table view is pushed on the left hand side
• The new view on the left side can update the detail view.

I can accomplish both tasks BUT NOT TOGETHER. I mean I can make a multi-level table view in the RootController.(HERE you can find the working source code).

Or I can make a single-level table view in the RootController which can update the detailViewController (here there is the source code:http://www.megaupload.com/?d=D6L0463G).

Can anyone tell me how to make a multi-level table in the RootController which can update a detailViewController?

There is more source code at the link but below is the method in which I presume I have to declare a new detailViewController (which has to be put in the UISplitViewController):

- (void)tableView:(UITableView *)TableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

NSDictionary *dictionary = [self.tableDataSource objectAtIndex:indexPath.row];

//Get the children of the present item.
NSArray *Children = [dictionary objectForKey:@"Children"];

//
if([Children count] == 0) {
    /*
    Create and configure a new detail view controller appropriate for the selection.
    */
    NSUInteger row = indexPath.row;
    UIViewController <SubstitutableDetailViewController> *detailViewController = nil;

    if (row == 0) {
        FirstDetailViewController *newDetailViewController = [[FirstDetailViewController alloc]initWithNibName:@"FirstDetailView" bundle:nil];
        detailViewController = newDetailViewController;
    }

    if (row == 1) {
        SecondDetailViewController *newDetailViewController = [[SecondDetailViewController alloc]initWithNibName:@"SecondDetailView" bundle:nil];
        detailViewController = newDetailViewController;
    }

    // Update the split view controller's view controllers array.
    NSArray *viewControllers = [[NSArray alloc] initWithObjects:self.navigationController, detailViewController, nil];
    splitViewController.viewControllers = viewControllers//nothing happens.....
    [viewControllers release];// 
}

else {

    //Prepare to tableview.
    RootViewController *rvController = [[RootViewController alloc]initWithNibName:@"RootViewController" bundle:[NSBundle mainBundle]];

    //Increment the Current View
    rvController.current_level += 1;

    //Set the title;
    rvController.current_title = [dictionary objectForKey:@"Title"];

    //Push the new table view on the stack
    [self.navigationController pushViewController:rvController animated:YES];

    rvController.tableDataSource = Children;
    [rvController.tableView reloadData]; //without this instrucion,items won't be loaded inside the second level of the table 

    [rvController release];
    }
}