title: Flutter Error: MediaQuery.of() called with a context that does not contain a MediaQuery
body: <p>I have been trying to get the size of the whole context view in Flutter. But every time I try I'm getting the above mentioned error. 
  Here's my code:</p>
  
  <pre><code>import 'package:flutter/material.dart';
  
  void main =&gt; runApp(new MyApp());
  
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
  
      final size = MediaQuery.of(context).size;
      return new MaterialApp(
        home: new Scaffold(),
      );
    }
  }
  </code></pre>
  
  <p>Note: I also tried with a <code>StatefulWidget</code>. 
  Please, help me find what I'm doing wrong here.</p>