iOS: Open and close with push event ViewController. (NavigationController required)

gistfile1.m

// Open
UIViewController *viewController = [self.storyboard instantiateViewControllerWithIdentifier:@"ViewControllerStoryboardID"];
// Or (but no use Storyboard)
CustomViewController *viewController = [[CustomViewController alloc] init]

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


// Close
[self.navigationController popViewControllerAnimated:NO];