如何解决使用 flutter 为 macOS 录制音频的问题？

Question

我试图在 macOS 中录制音频，但发现生成的音频文件有问题，我的意思是当我尝试播放录制的文件时，听不到任何声音，就像是空的一样。

我用来录制音频的包：record

用于播放音频：audioplayers

结果

完整代码：

main.dart

：

import 'package:flutter/material.dart';

import 'recorder/audio_recorder_sample.dart';

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

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
          useMaterial3: true,
        ),
        home: const AudioRecorderSample());
  }
}

audio_recorder_sample.dart

：

import 'package:flutter/material.dart';
import 'package:flutter_audio_rec/recorder/widgets/recorder.dart';

import '../player/linear_audio_player.dart';

class AudioRecorderSample extends StatefulWidget {
  const AudioRecorderSample({super.key});

  @override
  State<AudioRecorderSample> createState() => _AudioRecorderSampleState();
}

class _AudioRecorderSampleState extends State<AudioRecorderSample> {
  String? recordedAudioPath;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          if (recordedAudioPath?.isNotEmpty ?? false) ...[
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 10.0),
              child: LinearAudioPlayer(
                  source: recordedAudioPath ?? '',
                  onDelete: () {
                    setState(() {
                      recordedAudioPath = null;
                    });
                  }),
            ),
            const SizedBox(
              height: 10,
            ),
          ],
          Recorder(onStop: (path) {
            debugPrint("RECORDED AUDIO FILE====================>$path");
            setState(() {
              recordedAudioPath = path;
            });
          })
        ],
      ),
    );
  }
}

recorder.dart

：

import 'dart:async';
import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:record/record.dart';
import 'package:path_provider/path_provider.dart';

class Recorder extends StatefulWidget {
  final void Function(String path) onStop;

  const Recorder({super.key, required this.onStop});

  @override
  State<Recorder> createState() => _RecorderState();
}

class _RecorderState extends State<Recorder> {
  int _recordDuration = 0;
  Timer? _timer;
  late final AudioRecorder _audioRecorder;

  StreamSubscription<RecordState>? _recordSub;
  RecordState _recordState = RecordState.stop;
  StreamSubscription<Amplitude>? _amplitudeSub;
  Amplitude? _amplitude;
  late Directory appDirectory;
  String? path;
  bool recordingDone = false;
  bool isRecording = false;

  void getDir() async {
    appDirectory = await getApplicationDocumentsDirectory();
    path =
        "${appDirectory.path}/${DateTime.now().millisecondsSinceEpoch}.mp3"; //recording
  }

  @override
  void initState() {
    getDir();
    _audioRecorder = AudioRecorder();

    _recordSub = _audioRecorder.onStateChanged().listen((recordState) {
      _updateRecordState(recordState);
    });

    _amplitudeSub = _audioRecorder
        .onAmplitudeChanged(const Duration(milliseconds: 300))
        .listen((amp) {
      setState(() => _amplitude = amp);
    });

    super.initState();
  }

  Future<void> _start() async {
    setState(() => recordingDone = false);
    try {
      
      if (await _audioRecorder.hasPermission()) {
        const encoder = AudioEncoder.aacLc;

        if (!await _isEncoderSupported(encoder)) {
          return;
        }

        final devs = await _audioRecorder.listInputDevices();
        debugPrint(devs.toString());

        const config = RecordConfig(encoder: encoder, numChannels: 1);
        _audioRecorder.start(config, path: path ?? '');

        _recordDuration = 0;

        _startTimer();
      }
    } catch (e) {
      if (kDebugMode) {
        print(e);
      }
    }
  }

  Future<void> _stop() async {
    path = await _audioRecorder.stop();

    if (path != null) {
      widget.onStop(path!);
      setState(() {
        recordingDone = true;
      });
    }
  }

  Future<void> _pause() => _audioRecorder.pause();

  Future<void> _resume() => _audioRecorder.resume();

  void _updateRecordState(RecordState recordState) {
    setState(() => _recordState = recordState);

    switch (recordState) {
      case RecordState.pause:
        _timer?.cancel();
        break;
      case RecordState.record:
        _startTimer();
        break;
      case RecordState.stop:
        _timer?.cancel();
        _recordDuration = 0;
        break;
    }
  }

  Future<bool> _isEncoderSupported(AudioEncoder encoder) async {
    final isSupported = await _audioRecorder.isEncoderSupported(
      encoder,
    );

    if (!isSupported) {
      debugPrint('${encoder.name} is not supported on this platform.');
      debugPrint('Supported encoders are:');

      for (final e in AudioEncoder.values) {
        if (await _audioRecorder.isEncoderSupported(e)) {
          debugPrint('- ${encoder.name}');
        }
      }
    }

    return isSupported;
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            _buildRecordStopControl(),
            const SizedBox(width: 20),
            _buildPauseResumeControl(),
            const SizedBox(width: 20),
            _buildText(),
          ],
        ),
        if (_amplitude != null) ...[
          const SizedBox(height: 40),
          Text('Current: ${_amplitude?.current ?? 0.0}'),
          Text('Max: ${_amplitude?.max ?? 0.0}'),
        ],
      ],
    );
  }

  @override
  void dispose() {
    _timer?.cancel();
    _recordSub?.cancel();
    _amplitudeSub?.cancel();
    _audioRecorder.dispose();
    super.dispose();
  }

  Widget _buildRecordStopControl() {
    late Icon icon;
    late Color color;

    if (_recordState != RecordState.stop) {
      icon = const Icon(Icons.stop, color: Colors.red, size: 30);
      color = Colors.red.withOpacity(0.1);
    } else {
      final theme = Theme.of(context);
      icon = const Icon(Icons.mic, color: Colors.black, size: 30);
      color = theme.primaryColor.withOpacity(0.1);
    }

    return ClipOval(
      child: Material(
        color: color,
        child: InkWell(
          child: SizedBox(width: 56, height: 56, child: icon),
          onTap: () {
            (_recordState != RecordState.stop) ? _stop() : _start();
          },
        ),
      ),
    );
  }

  Widget _buildPauseResumeControl() {
    if (_recordState == RecordState.stop) {
      return const SizedBox.shrink();
    }

    late Icon icon;

    if (_recordState == RecordState.record) {
      icon = const Icon(Icons.pause, color: Colors.red, size: 30);
    } else {
      icon = const Icon(Icons.play_arrow, color: Colors.red, size: 30);
    }

    return ClipOval(
      child: Material(
        // color: color,
        child: InkWell(
          child: SizedBox(width: 56, height: 56, child: icon),
          onTap: () {
            (_recordState == RecordState.pause) ? _resume() : _pause();
          },
        ),
      ),
    );
  }

  Widget _buildText() {
    if (_recordState != RecordState.stop) {
      return _buildTimer();
    }

    return const Text("Waiting to record");
  }

  Widget _buildTimer() {
    final String minutes = _formatNumber(_recordDuration ~/ 60);
    final String seconds = _formatNumber(_recordDuration % 60);

    return Text(
      '$minutes : $seconds',
      style: const TextStyle(color: Colors.red),
    );
  }

  String _formatNumber(int number) {
    String numberStr = number.toString();
    if (number < 10) {
      numberStr = '0$numberStr';
    }

    return numberStr;
  }

  void _startTimer() {
    _timer?.cancel();

    _timer = Timer.periodic(const Duration(seconds: 1), (Timer t) {
      setState(() => _recordDuration++);
    });
  }
}

linear_audio_player.dart

：

import 'dart:async';

import 'package:audioplayers/audioplayers.dart' as ap;
import 'package:audioplayers/audioplayers.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

class LinearAudioPlayer extends StatefulWidget {
  final String source;
  final void Function()?  onDelete;

  const LinearAudioPlayer({
    super.key,
    required this.source,
    required this.onDelete,
  });

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

class LinearAudioPlayerState extends State<LinearAudioPlayer> {
  static const double _controlSize = 56;

  final _audioPlayer = ap.AudioPlayer();
  // final _audioPlayer = ap.AudioPlayer()..setReleaseMode(ReleaseMode.stop);
  late StreamSubscription<void> _playerStateChangedSubscription;
  late StreamSubscription<Duration?> _durationChangedSubscription;
  late StreamSubscription<Duration> _positionChangedSubscription;
  Duration? _position;
  Duration? _duration;

  @override
  void initState() {
    _init();

    super.initState();
  }

  _init() async {
    _playerStateChangedSubscription =
        _audioPlayer.onPlayerComplete.listen((state) async {
      await stop();
    });
    _positionChangedSubscription = _audioPlayer.onPositionChanged.listen(
      (position) => setState(() {
        _position = position;
      }),
    );
    _durationChangedSubscription = _audioPlayer.onDurationChanged.listen(
      (duration) => setState(() {
        _duration = duration;
      }),
    );

    await _audioPlayer.setSource(_source);
  }

  @override
  void dispose() {
    _playerStateChangedSubscription.cancel();
    _positionChangedSubscription.cancel();
    _durationChangedSubscription.cancel();
    _audioPlayer.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        return Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Row(
              mainAxisSize: MainAxisSize.max,
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: <Widget>[
                _buildControl(),
                _buildSlider(constraints.maxWidth),
                Text('${_duration ?? 0.0}'),
              ],
            ),
            //
          ],
        );
      },
    );
  }

  Widget _buildControl() {
    Icon icon;
    Icon deleteIcon = const Icon(Icons.delete, color: Colors.black, size: 30);

    if (_audioPlayer.state == ap.PlayerState.playing) {
      icon = const Icon(Icons.pause, color: Colors.black, size: 30);
    } else {
      icon = const Icon(Icons.play_arrow, color: Colors.black, size: 30);
    }

    return Row(
      children: [
        InkWell(
          onTap: widget.onDelete,
          child:  SizedBox(
              width: _controlSize, height: _controlSize, child: deleteIcon),
        ),
        InkWell(
          child:
              SizedBox(width: _controlSize, height: _controlSize, child: icon),
          onTap: () {
            if (_audioPlayer.state == ap.PlayerState.playing) {
              pause();
            } else {
              play();
            }
          },
        ),
      ],
    );
  }

  Widget _buildSlider(double widgetWidth) {
    bool canSetValue = false;
    final duration = _duration;
    final position = _position;

    if (duration != null && position != null) {
      canSetValue = position.inMilliseconds > 0;
      canSetValue &= position.inMilliseconds < duration.inMilliseconds;
    }

    return Expanded(
      // width: width,
      child: Slider(
        activeColor: Colors.black,
        inactiveColor: Colors.grey,
        onChanged: (v) {
          if (duration != null) {
            final position = v * duration.inMilliseconds;
            _audioPlayer.seek(Duration(milliseconds: position.round()));
          }
        },
        value: canSetValue && duration != null && position != null
            ? position.inMilliseconds / duration.inMilliseconds
            : 0.0,
      ),
    );
  }

  Future<void> play() async =>
      await _audioPlayer.play(_source, ctx: ap.AudioContext());

  Future<void> pause() async {
    await _audioPlayer.pause();
    setState(() {});
  }

  Future<void> stop() async {
    await _audioPlayer.stop();
    setState(() {});
  }

  Source get _source => kIsWeb
      ? ap.UrlSource(widget.source)
      : ap.DeviceFileSource(
          widget.source,
        );
}

Answer 1

经过大量研发后发现我犯了这个错误真是太愚蠢了。真的只是浪费了几天。

只需要在 Xcode 的

Audio Input

下启用选项 (

Signing & Capabilities

)。