title: wrapping Scaffold with Container for gradient background, How to set gradient to container background in flutter?
body: <p>I'd like to wrap a <code>Scaffold</code> with a <code>Container</code> in order to get a gradient background that's also underneath the <code>AppBar</code>. Basically a full screen <code>gradient</code> background. However, my attempt doesn't do anything.
  Is there another way of doing it, where I can keep the <code>AppBar</code> functionality but have it on top of a <code>gradient</code> that spans the whole screen?</p>
  <pre><code>import 'package:flutter/material.dart';
  
  void main() =&gt; runApp(MyApp());
  
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        title: 'Test',
        theme: ThemeData(
          primarySwatch: Colors.yellow,
        ),
        home: MyHomePage(title: 'Test'),
      );
    }
  }
  
  class MyHomePage extends StatelessWidget {
    MyHomePage({Key key, this.title}) : super(key: key);
  
    final String title;
  
    @override
    Widget build(BuildContext context) {
      return Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topRight,
            end: Alignment.bottomLeft,
            stops: [0.1, 0.5, 0.7, 0.9],
            colors: [
              Colors.yellow[800],
              Colors.yellow[700],
              Colors.yellow[600],
              Colors.yellow[400],
            ],
          ),
        ),
        child: Scaffold(
          appBar: AppBar(
            title: Icon(Icons.menu),
            backgroundColor: Color(0x00000000),
            elevation: 0.0,
          ),
          body: Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: &lt;Widget&gt;[
                Text(
                  'dummy text',
                ),
                Text(
                  '5',
                  style: Theme.of(context).textTheme.display1,
                ),
                FloatingActionButton(
                  backgroundColor: Colors.white,
                  foregroundColor: Colors.black45,
                  elevation: 0.0,
                  onPressed: () {},
                  tooltip: 'Play',
                  child: Icon(Icons.play_arrow),
                ),
              ],
            ),
          ),
        ),
      );
    }
  }
  </code></pre>