How to update detailViewController.detailItem from multi-level nav in rootViewController - xcode

Question

this is my first post so please be gently.
I am using the basic Split View-based application within xcode, but have edited it so that the rootViewController does not simply update the detailViewController, but instead pushes a new UITableViewController (taskViewController) onto the navigation stack.
My problem is, that nothing happens when I now call the following from my taskViewController:
detailViewController.detailItem = [NSString stringWithFormat:#"Row %d", indexPath.row];
If I call this from rootViewController, instead of pushing a new UITableView onto the stack, it works.
Here is my code from rootViewController when a cell is selected:
- (void)tableView:(UITableView *)aTableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
TaskViewController *taskViewController = [[TaskViewController alloc] init];
taskViewController.title = [NSString stringWithFormat:#"Unit %d",indexPath.row];
[self.navigationController pushViewController:taskViewController animated:YES];
[taskViewController release];
}
Have I done something wrong here? Am I using the navigation controller correctly within the rootViewController of the UISplitViewController?

Answer 1

Your rootViewController can access detailViewController because it has a referance to it. if you push a new controller onto the nav stack, then its not automatically going to know about DetailViewController.
Have you NSLog'd detailViewController in your taskVC to see if it has a pointer?
You would typically set this when you are creating it like this:
- (void)tableView:(UITableView *)aTableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
TaskViewController *taskViewController = [[TaskViewController alloc] init];
taskViewController.title = [NSString stringWithFormat:#"Unit %d",indexPath.row];
taskViewController.detailViewController = self.detailViewController;
[self.navigationController pushViewController:taskViewController animated:YES];
[taskViewController release];
}