title: Flutter global BottomAppBar with different AppBars in each Page
body: <p>I want a global BottomAppBar which I want to define in my MaterialApp.</p>
  <p>My current MaterialApp:</p>
  <pre><code>return MaterialApp(
    initialRoute: '/overview',
    routes: {
      '/overview': (context) =&gt; OverViewPage(),
      '/summary': (context) =&gt; SummaryPage(),
      '/record': (context) =&gt; RecordPage(&quot;&quot;),
      '/calendar': (context) =&gt; Calendar(),
      '/piechart': (context) =&gt; PieChartPage()
    },
    debugShowCheckedModeBanner: false,
    title: 'Flutter Demo',
    theme: lightTheme,
    home: OverViewPage(),
  );
  </code></pre>
  <p>In every Route is a own <code>Scaffold</code> because I need to specify my <code>AppBar</code> actions and the <code>FloatingActionButton</code> individually for each page. But when I wrap the <code>home</code> in a <code>Scaffold</code> and make the body of the <code>Scaffold</code> to each page, I have two <code>Scaffolds</code> stacked in each other, which is not possible.</p>
  <p>So basically I need an BottomAppBar in my Material App, but need to override the AppBar and the FloatingActionButton in each page.</p>