navigationController = null in TableViewController's pushViewController method (popover) - ios

Question

First of all, sorry for my English.
I'm trying to do an app for iPad with a navigation controller which pushes view controllers when a button "Next" is selected. But I also want to have a popover, called from a button in the nav bar, that allows the user to "jump" from one view controller to another, pushing it with the tableView:didSelectRowAtIndexPath: and the pushViewController:animated: methods, but it's not working.
Summary:
Tab bar -> switches between FirstViewController and SecondViewController (works just fine)
Nav bar (button Next) -> switches between SecondViewController, FirstSlideController and SecondSlideController (it's also good)
Popover -> user selects SecondViewController, FirstSlideController or SecondSlideController (here's the problem!)
Codes:
AppDelegate
UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil];
UINavigationController *navigationController1 = [[UINavigationController alloc] initWithRootViewController:viewController1];
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
UINavigationController *navigationController2 = [[UINavigationController alloc] initWithRootViewController:viewController2];
self.tabBarController = [[UITabBarController alloc] init];
self.tabBarController.viewControllers = #[navigationController1, navigationController2];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
return YES;
TableViewController(popover)'s didSelectRowAtIndexPath method:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if(indexPath.row == 0){
FirstSlideController *detailViewController = [[FirstSlideController alloc] initWithNibName:#"FirstSlideController" bundle:nil];
[self.navigationController pushViewController:detailViewController animated:YES];
}
else if(indexPath.row == 1){
SecondSlideController *detailViewController = [[SecondSlideController alloc] initWithNibName:#"SecondSlideController" bundle:nil];
[self.navigationController pushViewController:detailViewController animated:YES];
}
else{
SecondViewController *detailViewController = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
[self.navigationController pushViewController:detailViewController animated:YES];
}
}
SecondViewController (with delegate suggested by maros)
-(void) showPopover:(id) sender
{
TableViewController *PopoverView = [[TableViewController alloc] initWithNibName:#"TableViewController" bundle:nil];
self.popOver = [[UIPopoverController alloc] initWithContentViewController:PopoverView];
self.popOver.delegate = self;
[self.popOver presentPopoverFromBarButtonItem:self.navigationItem.leftBarButtonItem permittedArrowDirections: UIPopoverArrowDirectionUp animated: YES];
}
I tried to print self.navigationController and it says it's null. I'd appreciate any help.
Thank you.

Answer 1

Presnented UIPopoverController is not pushed on the navigation stack in the view controller from which it was presented. It is a separate view controller.
Therefore the navigationController inside the popover is nil.
What I would recommend you is to create a delegate MyNavigationPopoverDelegate (the class that creates a popover (PopoverController). Pass it's instance as an delegate to the TableViewController.
After users clicks on some button inside popover, call delegate's method to processes button clicks (myNavigationPopover:(UIPopoverController*)popover clickedButtonAtIndex:(NSInteger)buttonIndex).
Then maybe dismiss delegate?
and finally change navigation however you want! :)
#protocol MyNavigationPopoverDelegate
- (void) myNavigationPopover:(UIPopoverController*)popover clickedButtonAtIndex:(NSInteger)buttonIndex;
#end
#interface TableViewController : UITableVieController // your viewController in popover
... // your code
#property (nonatomic, weak) NSObject <MyNavigationPopoverDelegate> * delegate;
... // your code
#end
#implementation TableViewController
...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[self.delegate myNavigationPopover:self clickedButtonAtIndex:indexPath.row];
}
...
#end
// defines that SecondViewController implements the delegate's method
#interface SecondViewController <MyNavigationPopoverDelegate> : UIViewController
// your code
#end
// code where you presenting popover
#implementation SecondViewController
// This is the method that is executed after your button press and it is responsible for presenting a popover
- (void) presentPopover{
...
myPopover.delegate = self; // setting the delegate
[myPopover presentPopoverFromXXX ...]; // however you present it
...
}
- (void) myNavigationPopover:(UIPopoverController*)popover clickedButtonAtIndex:(NSInteger)buttonIndex
{
UINavigationController *currentNavigationController = ; // get the navigation controller from the tab bar
if(buttonIndex == 0){
FirstSlideController *detailViewController = [[FirstSlideController alloc] initWithNibName:#"FirstSlideController" bundle:nil];
[currentNavigationController pushViewController:detailViewController animated:YES];
}
else if(buttonIndex == 1){
SecondSlideController *detailViewController = [[SecondSlideController alloc] initWithNibName:#"SecondSlideController" bundle:nil];
[currentNavigationController pushViewController:detailViewController animated:YES];
}
else{
SecondViewController *detailViewController = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
[currentNavigationController pushViewController:detailViewController animated:YES];
}
}
#end;