Flutter 录音播放插件flutter_sound 的使用以及IOS无法录音问题解决

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依赖：flutter_sound：^9.2.9
地址：https://pub.flutter-io.cn/packages/flutter_sound/install
音频：audio_session: ^0.1.6
地址：https://pub.flutter-io.cn/packages/audio_session
依赖：permission_handler: ^8.1.2
地址：https://pub.flutter-io.cn/packages/permission_handler/versions/8.1.2/install

安卓配置
需要配置 AndroidManifest.xml 录音权限

苹果配置
info.plist
NSMicrophoneUsageDescription
需要您的同意，才能访问麦克风
podfile
post_install do |installer|
installer.pods_project.targets.each do |target|
flutter_additional_ios_build_settings(target)
target.build_configurations.each do |config|
config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
'$(inherited)',
'PERMISSION_MICROPHONE=1']
end
end
end
iOS工程中增加libc++.tbd库,Build Phases->Link Binary With...

代码块：

引入头文件

import 'package:audio_session/audio_session.dart';
import >'package:flutter_sound_platform_interface/flutter_sound_recorder_platform_interface.dart';
import 'package:flutter_sound/flutter_sound.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:path_provider/path_provider.dart';

声明对象

 FlutterSoundRecorder recorderModule = FlutterSoundRecorder();
 FlutterSoundPlayer playerModule = FlutterSoundPlayer();

定义初始化方法

void init() async {
//开启录音
   await recorderModule.openRecorder();
   //设置订阅计时器
   await recorderModule
       .setSubscriptionDuration(const Duration(milliseconds: 10));

   //设置音频
   final session = await AudioSession.instance;
   await session.configure(AudioSessionConfiguration(
     avAudioSessionCategory: AVAudioSessionCategory.playAndRecord,
      avAudioSessionCategoryOptions:
         AVAudioSessionCategoryOptions.allowBluetooth |
             AVAudioSessionCategoryOptions.defaultToSpeaker,
     avAudioSessionMode: AVAudioSessionMode.spokenAudio,
     avAudioSessionRouteSharingPolicy:
         AVAudioSessionRouteSharingPolicy.defaultPolicy,
     avAudioSessionSetActiveOptions: AVAudioSessionSetActiveOptions.none,
     androidAudioAttributes: const AndroidAudioAttributes(
       contentType: AndroidAudioContentType.speech,
       flags: AndroidAudioFlags.none,
       usage: AndroidAudioUsage.voiceCommunication,
     ),
     androidAudioFocusGainType: AndroidAudioFocusGainType.gain,
     androidWillPauseWhenDucked: true,
   ));
   await playerModule.closePlayer();
   await playerModule.openPlayer();
   await playerModule
      .setSubscriptionDuration(const Duration(milliseconds: 10));
  }

动态权限

 Future getPermissionStatus() async {
   Permission permission = Permission.microphone;
   //granted 通过，denied 被拒绝，permanentlyDenied 拒绝且不在提示
   PermissionStatus status = await permission.status;
   if (status.isGranted) {
     return true;
   } else if (status.isDenied) {
     requestPermission(permission);
   } else if (status.isPermanentlyDenied) {
     openAppSettings();
   } else if (status.isRestricted) {
     requestPermission(permission);
   } else {}
   return false;
 }

 ///申请权限
 void requestPermission(Permission permission) async {
   PermissionStatus status = await permission.request();
   if (status.isPermanentlyDenied) {
     openAppSettings();
   }
 }

录音、播放

/// 开始录音
 _startRecorder() async {
   try {
     var status = await getPermissionStatus();

     Directory tempDir = await getTemporaryDirectory();
     var time = DateTime.now().millisecondsSinceEpoch;
     String path = 
          '${tempDir.path}}-$time${ext[Codec.aacADTS.index]}' ;

     print('===>  准备开始录音');
     await recorderModule.startRecorder(
         toFile: path,
         codec: Codec.aacADTS,
         bitRate: 8000,,
         sampleRate: 8000,,
         audioSource: AudioSource.microphone);
     print('===>  开始录音');

     /// 监听录音
     recorderModule.onProgress!.listen((e) {
       if (e != null && e.duration != null) {
         DateTime date = new DateTime.fromMillisecondsSinceEpoch(
             e.duration.inMilliseconds,
             isUtc: true);

         if (date.second >= _maxLength) {
           print('===>  到达时常停止录音');
           _stopRecorder();
         }
        setState(() {
           print("时间：${date.second}");
           print("当前振幅：${e.decibels}");
           num = date.second;
           setState(() {
             if (e.decibels! > 0 && e.decibels! < 10) {
               voiceIco = "Asset/message/icon_diyinliang.png";
             } else if (e.decibels! > 20 && e.decibels! < 30) {
               voiceIco = "Asset/message/icon_zhongyinliang.png";
             } else if (e.decibels! > 30 && e.decibels! < 40) {
               voiceIco = "Asset/message/icon_gaoyinliang.png";
             } else if (e.decibels! > 40 && e.decibels! < 50) {
               voiceIco = "Asset/message/icon_zhongyinliang.png";
             } else if (e.decibels! > 50 && e.decibels! < 60) {
               voiceIco = "Asset/message/icon_diyinliang.png";
             } else if (e.decibels! > 70 && e.decibels! < 100) {
               voiceIco = "Asset/message/icon_gaoyinliang.png";
             } else {
               voiceIco = "Asset/message/icon_diyinliang.png";
             }
           });
         });
       }
     });
     this.setState(() {
       _state = RecordPlayState.recording;
       _path = path;
       print("path == $path");
     });
   } catch (err) {
     setState(() {
       print(err.toString());
    _stopRecorder();
       _state = RecordPlayState.record;
     });
   }
 }

 /// 结束录音
 _stopRecorder() async {
   try {
     await recorderModule.stopRecorder();
     print('stopRecorder===> fliePath:$_path');
     widget.stopRecord!(_path, num);
   } catch (err) {
     print('stopRecorder error: $err');
   }
   setState(() {
     _state = RecordPlayState.play;
   });
 }
 ///开始播放，这里做了一个播放状态的回调
 void startPlayer(path, {Function(dynamic)? callBack}) async {
   try {
     if (path.contains('http')) {
       await playerModule.startPlayer(
          fromURI: path,
           codec: Codec.mp3,
           sampleRate: 44000,
           whenFinished: () {
             stopPlayer();
             callBack!(0);
           });
     } else {
       //判断文件是否存在
       if (await _fileExists(path)) {
         if (playerModule.isPlaying) {
           playerModule.stopPlayer();
         }
         await playerModule.startPlayer(
             fromURI: path,
             codec: Codec.aacADTS,
             sampleRate: 44000,
             whenFinished: () {
               stopPlayer();
               callBack!(0);
             });
       } else {}
     }
     //监听播放进度
     playerModule.onProgress!.listen((e) {});
     callBack!(1);
   } catch (err) {
     callBack!(0);
   }
 }

 /// 结束播放
 void stopPlayer() async {
   try {
     await playerModule.stopPlayer();
   } catch (err) {}
 }

 ///获取播放状态
 Future getPlayState() async {
   return await playerModule.getPlayerState();
 }

 /// 释放播放器
 void releaseFlauto() async {
   try {
     await playerModule.closePlayer();
   } catch (e) {
     print(e);
   }
}

 /// 判断文件是否存在
 Future _fileExists(String path) async {
   return await File(path).exists();
 }

释放

 @override
 void dispose() {
   // TODO: implement dispose
   super.dispose();
   recorderModule.closeRecorder();
   playerModule.closePlayer();
 }

联调真机运行，安卓录音播放一气呵成没任何问题，但苹果手机上会发现无法录制，在进度监听里返回的date秒数一直是0，这就很苦恼经过资料查找最终找到问题所在并解决

修改机型对应filepath后缀音频格式

String path =GetPlatform.isAndroid
         ? '${tempDir.path}}-$time.aac'
         : '${tempDir.path}}-$time.wav';

修改采样、比特率

await recorderModule.startRecorder(
         toFile: path,
         codec: GetPlatform.isAndroid ? Codec.aacADTS : Codec.pcm16WAV,
         bitRate: 1411200,
         sampleRate: 44100,
         audioSource: AudioSource.microphone);
     print('===>  开始录音');

细心的你能发现bitRate由8000换为1411200，sampleRate由8000换为44100，这不是瞎换的,这是为了提升音频的高质量，以采样率为44.1KHz，以16bit采样，声道数为2为例，所以sampleRate：44100，计算出比特率44100162 = 1411200
出现这个问题的根本原因是iOS不兼容.aac,说一句这个插件不支持mp3。