title: How to refresh Ionic 4 page after a navigateBack
body: <p>I have an edit page which opens with a :</p>
  
  <pre><code> this.navController.navigateForward('AddEvent')
  </code></pre>
  
  <p>and when the event is finished uses :</p>
  
  <pre><code> this.navController.navigateBack('MainPage');
  </code></pre>
  
  <p>to show the new event...except the page is not refreshing to show it...</p>
  
  <ul>
  <li>have looked at page events fired after pop...none</li>
  <li>have fired an event to be subscribed to but says "Cannot read property 'fireEvent' of undefined" (meaning 'this' as I used this.fireEvent();) so the page obviously needs to be fully instantiated.</li>
  <li>have successfully done it previously with an observable but not using one this time....just an array.</li>
  <li>have seen where you can pass the page object to the new page and use the object to call the refresh function...but have only seen this in Version 3, not with the new angular routing system.</li>
  </ul>
  
  <p>Anybody have some successful ideas?</p>