Open flutter dialog after navigation : <p>I call Navigator pushReplacement to show a new view within my flutter app and want to immediately pop up a simple dialog to introduce the page to the user. (I want the user to be able to see the new view in the background)</p>

<p>If I call showDialog within the build method of a widget, and then subsequently return a widget (scaffold) from the build method I get errors stating that flutter is already drawing a widget. I expect I need to listen on a build complete event and then call showDialog.</p>

<p>Guidance on how to do that much appreciated.</p>
