這是 milestone 1 的程式碼：

lib/main.dart:

import 'package:flutter/material.dart';
import 'package:happy_recorder/screens/audio_session.dart';
import 'package:happy_recorder/screens/my_home_page.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      initialRoute: '/',
      routes: {
        '/': (context) => MyHomePage(title: 'Happy Recorder v0.0'),
        '/audio': (context) => AudioSession(),
      },
    );
  }
}

lib/screens/my_home_page.dart:

import 'package:flutter/material.dart';
import 'package:happy_recorder/models/audio_rec.dart';

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  //int _counter = 0;
  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

  void _openDrawer() {
    _scaffoldKey.currentState!.openDrawer();
  } // _openDrawer()

  void _closeDrawer() {
    Navigator.of(context).pop();
  } // _closeDrawer()

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      key: _scaffoldKey,
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: ListView.builder(
        itemCount: audioRec.length,
        itemBuilder: (context, index) {
          return Card(
            child: ListTile(
              title: Text(audioRec[index].title),
              subtitle: Text(audioRec[index].description),
              trailing: Icon(
                Icons.play_arrow,
                color: Colors.blueAccent,
                //semanticLabel: 'Play $audioRec[index].title audio',
              ),
            ),
          );
        },
      ),
      drawer: Drawer(
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              const Text('This is the Drawer'),
              ElevatedButton(
                onPressed: _closeDrawer,
                child: const Text('Close Drawer'),
              ),
            ],
          ),
        ),
      ),
      bottomNavigationBar: BottomAppBar(
        shape: const CircularNotchedRectangle(),
        child: Container(height: 30.0),
      ),
      floatingActionButton: FloatingActionButton(
        //onPressed: _incrementCounter,
        onPressed: () {
          Navigator.pushNamed(context, '/audio');
        },
        tooltip: 'new recording',
        child: Icon(Icons.add),
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
    );
  }
}

lib/screens/audio_session.dart:

import 'package:flutter/material.dart';
import 'package:happy_recorder/models/audio_rec.dart';

class AudioSession extends StatefulWidget {
  @override
  _AudioSessionState createState() => _AudioSessionState();
}

class _AudioSessionState extends State<AudioSession> {
  int _selectedBottomBarItemIndex = 0;

  void _onBottomBarItemTapped(int index) {
    setState(() {
      _selectedBottomBarItemIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Record"),
        // automaticallyImplyLeading: false, // not display <- back btn
      ),
      body: Container(
        padding: const EdgeInsets.all(5.0),
        color: Colors.lightBlueAccent,
        child:
          Column(
            children: [
              Card(
                child: ListTile(
                  title: Text(audioRec[3].title),
                  subtitle: Text(audioRec[3].description),
                ),
              ),
              Container(
                width: double.infinity, // make it max width,
                padding: const EdgeInsets.all(10.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    // Dart 2.3 以上才支援
                    if (_selectedBottomBarItemIndex != 0)
                      Text(
                        "Bottom bar $_selectedBottomBarItemIndex selected",
                      )
                    else
                      Text("nothing selected"),
                    Text('Audio info'),
                  ],
                ),
              ),
            ],
          ),
      ),
      bottomNavigationBar: Container(
        height: 110,
        padding: const EdgeInsets.only(top: 10.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Column(
              children: [
                Ink(
                  decoration: const ShapeDecoration(
                    color: Colors.blueAccent,
                    shape: CircleBorder(),
                  ),
                  child: IconButton(
                    icon: const Icon(Icons.record_voice_over),
                    iconSize: 38,
                    color: Colors.white,
                    onPressed: () {
                      _onBottomBarItemTapped(1);
                    },
                  ),
                ),
                Text(
                  'record',
                  style: TextStyle(color: Colors.blueAccent.withOpacity(0.8)),
                ),
              ],
            ),
            Column(
              children: [
                Ink(
                  decoration: const ShapeDecoration(
                    color: Colors.blueAccent,
                    shape: CircleBorder(),
                  ),
                  child: IconButton(
                    icon: const Icon(Icons.stop),
                    iconSize: 38,
                    color: Colors.white,
                    onPressed: () {
                      Navigator.pop(context);
                    },
                  ),
                ),
                Text(
                  'stop',
                  style: TextStyle(color: Colors.blueAccent.withOpacity(0.8)),
                ),
              ],
            ),
          ],
        ),
      )
    );
  }
}

lib/models/audio_rec.dart:

class AudioRec {
  final String title;
  final String description;

  AudioRec(this.title, this.description);
}

// Generate test data
List audioRec = List.generate( 20, (i) => AudioRec(
    'Audio $i',
    'An audio description for audio $i title',
  ),
);