title: iOS Storyboard - Navigation Controller Not Working
body: <p>I am having trouble with a Navigation Controller in my iOS project which uses Storyboards.</p>
  
  <p>The main part of the project is a UITabBar.  When the app loads for the very first time the screen RegisterViewController is presented:</p>
  
  <p><img src="https://i.stack.imgur.com/JPxcP.png" alt="Register View Controller"></p>
  
  <p>When the user taps on the "Register" button a HTTP POST request is made, then upon receiving the response (JSON object) the screen QuestionnaireViewController is presented using:</p>
  
  <pre><code>UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
  
  QuestionnaireViewController *questionnaireViewController = [mainStoryboard instantiateViewControllerWithIdentifier:@"QuestionnaireView"];
  [questionnaireViewController setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
  [questionnaireViewController setQuestionsAndAnswers:_questionsAndAnswers];
  
  [self presentViewController:questionnaireViewController animated:NO completion:nil];
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/NqDsj.png" alt="Questionnaire View Controller"></p>
  
  <p>When the user taps on a cell in QuestionnaireViewController a message is sent to prepareForSegue:sender:</p>
  
  <pre><code>- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
  {
      UINavigationController *navigationController = segue.destinationViewController;
  
      AnswersViewController *answersViewController = [[navigationController viewControllers] objectAtIndex:0];
  
      NSIndexPath *indexPath = [self.tableView indexPathForCell:sender];
      NSArray *answers = [[_questionsAndAnswers objectAtIndex:indexPath.row] objectForKey:@"answers"];
  
      [answersViewController setAnswers:answers];
  }
  </code></pre>
  
  <p>At this point the app crashes with an error of:
  -[AnswersViewController viewControllers]: unrecognized selector sent to instance.</p>
  
  <p>Below is a more comprehensive overview of my storyboard, which may help in understanding where I have gone wrong:</p>
  
  <p><img src="https://i.stack.imgur.com/A3Yda.png" alt="Storyboard"></p>
  
  <p>I am stumped as to how to fix this, and am hoping that someone out there is able to help.</p>
  
  <p>Thanks,
  Nick</p>