title: Add child view controller to UINavigationController
body: <p>I'm trying to add a child view controller to a <code>UIViewController</code> contained in a <code>UINavigationController</code> with this code:</p>
  <pre><code>- (void)buttonTapped:(id)sender
  {
      MyChildController *viewController = [self.storyboard instantiateViewControllerWithIdentifier:@&quot;MyChild&quot;];
      [self addChildViewController:viewController];
      [self.view addSubview:viewController.view];
      [viewController didMoveToParentViewController:self];
  
  
      viewController.view.alpha = 0.0f;
      [UIView animateWithDuration:0.4 animations:^{
          viewController.view.alpha = 1.0f;
      }];
  }
  </code></pre>
  <p>But this is the result:</p>
  <p><img src="https://i.stack.imgur.com/rLPVH.png" alt="Image Result" /></p>
  <p>As you can see the <code>UINavigatioBar</code> and the <code>UIToolbar</code> are still on top of the child view controller. How can I put the child view controller on top of all? I've already tried to replace the code with:</p>
  <pre><code>[self.navigationController addChildViewController:viewController];
      [self.navigationController.view addSubview:viewController.view];
      [viewController didMoveToParentViewController:self.navigationController];
  </code></pre>
  <p>But in this way the <code>viewDidAppear:animated</code> of the <code>viewController</code> doesn't get called. I don't know, why.</p>