title: Showing bottomNavigationBar only when futurebuilder is built
body: <p>I have a bottom nav bar which contains a button. I want to display the button only when in the futurebuilder there is data and connection is done.</p>
  <p>So far, I have introduced a boolean variable called loadButton which is initially set to false. Then Inside my future builder, in the if condition of connectionSate = done, I set loadButton to true. And then I control the visibility of the bottomNavBar using this boolean variable.</p>
  <p>So far, the button is never visible. I only see a continuous loading spinner. How do I change the boolean value?</p>
  <p>Here's the code:</p>
  <pre><code>FutureBuilder( 
        future: _someFuture, 
        builder: (ctx,dataSnapshot){ 
        if(dataSnapshot.connectionState == ConnectionState.done) 
          loadButton = true; 
      }), 
      bottomNavigationBar: loadButton?MaterialButton(
                onPressed: () =&gt; {},
                child: Text(_register ? 'REGISTER' : 'LOGIN'),
              ):Center(child:Loading())
  </code></pre>