// Modify the code in the ChatScreenState class definition as follows.

Widget build(BuildContext context) {
  return new Scaffold(
    appBar: new AppBar(title: new Text("Friendlychat")),
    body: new Column(                                        //modified
      children: <Widget>[                                         //new
        new Flexible(                                             //new
          child: new ListView.builder(                            //new
            padding: new EdgeInsets.all(8.0),                     //new
            reverse: true,                                        //new
            itemBuilder: (_, int index) => _messages[index],      //new
            itemCount: _messages.length,                          //new
          ),                                                      //new
        ),                                                        //new
        new Divider(height: 1.0),                                 //new
        new Container(                                            //new
          decoration: new BoxDecoration(
            color: Theme.of(context).cardColor),                  //new
          child: _buildTextComposer(),                       //modified
        ),                                                        //new
      ],                                                          //new
    ),                                                            //new
  );
}