我从https://pub.dartlang.org/导入了一个名为audioplayer的软件包。我在我的.yaml文件依赖项中添加了依赖项：

flutter:
    sdk: flutter
  cupertino_icons: ^0.1.2
  audioplayers: ^0.15.1
assets:
    - assets/

note1.wav是我在assets文件夹中的音频文件。
然后在终端中运行命令flutter pub get。
下面是我的Flutter代码：

import 'package:flutter/material.dart';
import 'package:audioplayers/audio_cache.dart';

void main() => runApp(XylophoneApp());

class XylophoneApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: SafeArea(
          child: Center(
            child: FlatButton(
              onPressed: () {
                final player = AudioCache();
                player.play('note1.wav');
              },
              child: Text('click me'),
            ),
          ),
        ),
      ),
    );
  }
}

但是没有声音，相反，我得到了以下错误：

iOS => call startHeadlessService, playerId e24a78e3-1f9f-439a-8f55-c4a55386da4b
iOS => call play, playerId e24a78e3-1f9f-439a-8f55-c4a55386da4b
play!
isLocal: 1 1
volume: 1.000000 1
position: 0 (null)
setUrl /Users/pratteekshaurya/Library/Developer/CoreSimulator/Devices/13364636-6425-40FF-A7EC-9C2498EFA847/data/Containers/Data/Application/B2C9DBA6-8B70-4D3B-9463-5754D4556893/Library/Caches/note1.wav
player status: 1
iOS -> updateDuration...3.750000
iOS -> invokechannel
iOS -> onSoundComplete...
flutter: Fatal Error: Callback lookup failed!

我是新的Flutter，我不能找出是什么问题，因为我遵循了文件中给出的确切。