我正在尝试使用 flutter 的音频播放器库播放简单的声音。当我尝试时，出现无法加载资产错误。我已经在这个网站上解决了几个相关的问题，所有这些问题似乎都只建议检查pubspec.yaml文件上的缩进并运行flutter clean。我已经这样做了几次，但没有任何结果。Flutter Doctor没有发现任何问题。
当我单击应该导致播放声音的按钮时，我收到以下信息：
E/flutter (22727): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: Unable to load asset: assets/sounds/start.mp3
E/flutter (22727): #0 PlatformAssetBundle.load (package:flutter/src/services/asset_bundle.dart:221:7)
E/flutter (22727): <asynchronous suspension>
E/flutter (22727): #1 AudioCache._fetchAsset (package:audioplayers/audio_cache.dart:60:29)
E/flutter (22727): #2 AudioCache.fetchToMemory (package:audioplayers/audio_cache.dart:67:30)
E/flutter (22727): <asynchronous suspension>
E/flutter (22727): #3 AudioCache.load (package:audioplayers/audio_cache.dart:82:37)
E/flutter (22727): #4 AudioCache.getAbsoluteUrl (package:audioplayers/audio_cache.dart:140:23)
E/flutter (22727): #5 AudioCache.play (package:audioplayers/audio_cache.dart:103:24)
E/flutter (22727): #6 playSound (package:tick_tok_bio/player.dart:14:20)
E/flutter (22727): #7 MapsState.startNewRoute (package:tick_tok_bio/gps_tracking.dart:122:13)
E/flutter (22727): #8 MapsState.startStop.<anonymous closure> (package:tick_tok_bio/gps_tracking.dart:240:13) …