使用audioplayers开发木琴应用遇类型错误：String无法转为Source

你遇到的错误根源是audioplayers 1.x及以上版本的API变更：player.play()方法不再接受字符串路径，必须传入Source类型的对象（比如对应本地资源的AssetSource）。

错误信息明确提示：

"message": "The argument type 'String' can't be assigned to the parameter type 'Source'."

修正步骤： #

1. 配置音频资源
   确认note1.wav到note7.wav放在项目的assets目录下，然后在pubspec.yaml中声明资源：

   flutter:
     assets:
       - assets/note1.wav
       - assets/note2.wav
       - assets/note3.wav
       - assets/note4.wav
       - assets/note5.wav
       - assets/note6.wav
       - assets/note7.wav
       # 也可以用通配符简化：- assets/note*.wav
   

2. 修改playSound函数
   将原来的字符串路径替换为AssetSource对象：

   void playSound(int soundNumber) async {
     final player = AudioPlayer();
     await player.play(AssetSource('note$soundNumber.wav'));
   }
   

   如果音频文件在assets的子目录（比如assets/audio/），路径要对应写成AssetSource('audio/note$soundNumber.wav')。

修正后的完整代码： #

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

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

class XylophoneApp extends StatelessWidget {
  const XylophoneApp({super.key});

  void playSound(int soundNumber) async {
    final player = AudioPlayer();
    await player.play(AssetSource('note$soundNumber.wav'));
  }

  Expanded buildKey({Color? color, int? soundNumber}) {
    return Expanded(
      child: TextButton(
        style: TextButton.styleFrom(
          backgroundColor: color,
        ),
        onPressed: () {
          playSound(soundNumber!);
        },
        child: const Text(''),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        backgroundColor: Colors.black,
        body: SafeArea(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[
              buildKey(color: Colors.red, soundNumber: 1),
              buildKey(color: Colors.orange, soundNumber: 2),
              buildKey(color: Colors.yellow, soundNumber: 3),
              buildKey(color: Colors.green, soundNumber: 4),
              buildKey(color: Colors.teal, soundNumber: 5),
              buildKey(color: Colors.blue, soundNumber: 6),
              buildKey(color: Colors.purple, soundNumber: 7),
            ],
          ),
        ),
      ),
    );
  }
}

内容的提问来源于stack exchange，提问作者Shashwat Rai