How to add navigation controller programmatically?

Question

I use code below, but it is not loaded:

UIStoryboard * storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
self.mapViewController = [storyboard instantiateViewControllerWithIdentifier:@"MapViewController"];
self.navigationController = [[UINavigationController alloc]initWithRootViewController:self];

self.navigationBar = [[UINavigationBar alloc]init];
[self.view addSubview:self.navigationBar];

[self.navigationController.navigationController pushViewController:self.mapViewController animated:YES];

Answer 1

try as below

UIViewController *bbp=[[UIViewController alloc]initWithNibName:@"UIViewController" bundle:nil];
UINavigationController *passcodeNavigationController = [[UINavigationController alloc] initWithRootViewController:bbp];
// [self.navigationController presentModalViewController:passcodeNavigationController animated:YES];
  [self.navigationController pushViewController:passcodeNavigationController animated:YES];
  [passcodeNavigationController release];