Push new view controller from table view (subview) - ios

Question

I have a view controller that has two table view controllers as subviews.
When I click one of the cells in the table view controller, I would like it to push to a new view controller. However, it says self.navigationController and self.parentViewController.navigationController are (null).
Does anyone know how I can push a new view from a subview? Thanks!
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
ProductClass *productClass = [arrProducts objectAtIndex:indexPath.row];
ProductSingleViewController *productSingleViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"ProductSingleViewController"];
productSingleViewController.prod_title = productClass.title;
NSLog(#"VC1: %#, VC2: %#", self.navigationController, self.parentViewController.navigationController);
[self.parentViewController.navigationController pushViewController:productSingleViewController animated:YES];
}

Answer 1

One way to handle this is by setting a delegate method inside the UITableViewControllers. Add the delegate method to your parent view controller. It will get triggered whenever someone taps a cell inside the tables. From this delegate method you will be able to push a new view controller onto the stack.
In MyTableViewController.h:
#protocol MyTableDelegate <NSObject>
#required
- (void)selectedCellWithInfo:(NSDictionary *)info
#end
#interface MyTableViewController : UITableViewController {
id <MyTableDelegate> delegate;
}
#property (strong) id delegate;
In MyTableViewController.m:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[delegate selectedCellWithInfo:[myTableDataSource[indexPath.row]];
}
In MyMainViewController.h:
#import "MyTableViewController.h"
#interface MyMainViewController : UIViewController <MyTableDelegate>
In MyMainViewController.m:
- (void)viewDidLoad {
[super viewDidLoad];
myTableViewController.delegate = self;
}
- (void)selectedCellWithInfo:(NSDictionary *)info {
// Do something
}

Answer 2

The navigationController property of a view controller will return a valid navigation controller object only if the view controller is in a navigation controller's navigation stack.
If the PRoductSingleViewController is your rootviewcontroller
1. Drag and drop the navigation controller
2. set the navigation controller as rootviewcontroller.
3. Replace the navigation child Viewcontroller with your PRoductSingleViewController
Or you can manage it in app delegate.m class
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
_productSingleViewController = [[PRoductSingleViewController alloc]initWithNibName:#"PRoductSingleViewController" bundle:nil];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController: _productSingleViewController];
[self.window addSubview:navController.view];
[navController release];
[self.window makeKeyAndVisible];
return YES;
}