Flutter音频录制插件flutter_audio_recorder的使用

flutter_audio_recorder简介

English | 简体中文

flutter_audio_recorder 是一个支持音频录制、暂停、恢复和停止的 Flutter 插件，并且提供了访问音频电平表属性的功能（如 average power 和 peak power）。

支持平台

• Android
• iOS

代码示例

• Flutter应用示例（使用 AndroidX）
• Flutter应用示例（不使用 AndroidX）

安装

在 pubspec.yaml 文件中添加以下依赖：

dependencies:
  flutter_audio_recorder: ^0.5.0

然后运行 flutter pub get。

iOS权限配置

1. 在 Info.plist 文件中添加麦克风使用描述：

<key>NSMicrophoneUsageDescription</key>
<string>Can We Use Your Microphone Please</string>

1. 使用 hasPermission API 请求用户授权。

Android权限配置

1. 在 ./android/app/src/main/AndroidManifest.xml 中添加以下权限：

<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

1. 使用 hasPermission API 请求用户授权。

配置

iOS

• 部署目标版本需为 8.0 或更高。

Android

• 如果使用 AndroidX，请使用最新版本（0.5.x）。
• 如果使用旧版 Android，请使用旧版本（0.4.9）。

使用方法

推荐的 API 使用顺序为：hasPermission => init => start -> (pause <-> resume) * n -> stop。每次开始新的录音前都需要调用 init。

检查权限

首先检查权限，如果未设置则请求权限，否则返回录制权限的状态：

bool hasPermission = await FlutterAudioRecorder.hasPermissions;

初始化

在开始录音之前，初始化并检查文件是否存在：

var recorder = FlutterAudioRecorder("file_path.mp4"); // 支持 .wav .aac .m4a
await recorder.initialized;

或者指定音频格式：

var recorder = FlutterAudioRecorder("file_path", audioFormat: AudioFormat.AAC); // 或 AudioFormat.WAV
await recorder.initialized;

设置采样率

var recorder = FlutterAudioRecorder("file_path", audioFormat: AudioFormat.AAC, sampleRate: 22000); // 默认采样率为 16000
await recorder.initialized;

音频格式与扩展名映射

开始录音

await recorder.start();
var recording = await recorder.current(channel: 0);

获取录音详情

var current = await recording.current(channel: 0);
// print(current.status);

可以使用定时器每 50 毫秒访问一次详细信息（录音结束后取消定时器）：

new Timer.periodic(tick, (Timer t) async {
        var current = await recording.current(channel: 0);
        // print(current.status);
        setState(() {
        });
      });

录音对象属性

metering 属性

status 属性

暂停录音

await recorder.pause();

恢复录音

await recorder.resume();

停止录音

停止后，再次调用 init 来创建新的录音：

var result = await recorder.stop();
File file = widget.localFileSystem.file(result.path);

示例代码

以下是一个完整的示例代码，展示了如何使用 flutter_audio_recorder 进行音频录制、播放等操作：

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

import 'package:audioplayers/audioplayers.dart';
import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_audio_recorder/flutter_audio_recorder.dart';
import 'package:path_provider/path_provider.dart';

void main() {
  SystemChrome.setEnabledSystemUIOverlays([]);
  runApp(new MyApp());
}

class MyApp extends StatefulWidget {
  [@override](/user/override)
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return new MaterialApp(
      home: new Scaffold(
        body: SafeArea(
          child: new RecorderExample(),
        ),
      ),
    );
  }
}

class RecorderExample extends StatefulWidget {
  final LocalFileSystem localFileSystem;

  RecorderExample({localFileSystem})
      : this.localFileSystem = localFileSystem ?? LocalFileSystem();

  [@override](/user/override)
  State<StatefulWidget> createState() => new RecorderExampleState();
}

class RecorderExampleState extends State<RecorderExample> {
  FlutterAudioRecorder _recorder;
  Recording _current;
  RecordingStatus _currentStatus = RecordingStatus.Unset;

  [@override](/user/override)
  void initState() {
    super.initState();
    _init();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return new Center(
      child: new Padding(
        padding: new EdgeInsets.all(8.0),
        child: new Column(
            mainAxisAlignment: MainAxisAlignment.spaceAround,
            children: <Widget>[
              new Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: new FlatButton(
                      onPressed: () {
                        switch (_currentStatus) {
                          case RecordingStatus.Initialized:
                            {
                              _start();
                              break;
                            }
                          case RecordingStatus.Recording:
                            {
                              _pause();
                              break;
                            }
                          case RecordingStatus.Paused:
                            {
                              _resume();
                              break;
                            }
                          case RecordingStatus.Stopped:
                            {
                              _init();
                              break;
                            }
                          default:
                            break;
                        }
                      },
                      child: _buildText(_currentStatus),
                      color: Colors.lightBlue,
                    ),
                  ),
                  new FlatButton(
                    onPressed: _currentStatus != RecordingStatus.Unset ? _stop : null,
                    child: new Text("Stop", style: TextStyle(color: Colors.white)),
                    color: Colors.blueAccent.withOpacity(0.5),
                  ),
                  SizedBox(
                    width: 8,
                  ),
                  new FlatButton(
                    onPressed: onPlayAudio,
                    child: new Text("Play", style: TextStyle(color: Colors.white)),
                    color: Colors.blueAccent.withOpacity(0.5),
                  ),
                ],
              ),
              new Text("Status : $_currentStatus"),
              new Text('Avg Power: ${_current?.metering?.averagePower}'),
              new Text('Peak Power: ${_current?.metering?.peakPower}'),
              new Text("File path of the record: ${_current?.path}"),
              new Text("Format: ${_current?.audioFormat}"),
              new Text(
                  "isMeteringEnabled: ${_current?.metering?.isMeteringEnabled}"),
              new Text("Extension : ${_current?.extension}"),
              new Text(
                  "Audio recording duration : ${_current?.duration.toString()}")
            ]),
      ),
    );
  }

  _init() async {
    try {
      if (await FlutterAudioRecorder.hasPermissions) {
        String customPath = '/flutter_audio_recorder_';
        io.Directory appDocDirectory;
        if (io.Platform.isIOS) {
          appDocDirectory = await getApplicationDocumentsDirectory();
        } else {
          appDocDirectory = await getExternalStorageDirectory();
        }

        customPath = appDocDirectory.path +
            customPath +
            DateTime.now().millisecondsSinceEpoch.toString();

        _recorder =
            FlutterAudioRecorder(customPath, audioFormat: AudioFormat.WAV);

        await _recorder.initialized;
        var current = await _recorder.current(channel: 0);
        setState(() {
          _current = current;
          _currentStatus = current.status;
        });
      } else {
        Scaffold.of(context).showSnackBar(
            new SnackBar(content: new Text("You must accept permissions")));
      }
    } catch (e) {
      print(e);
    }
  }

  _start() async {
    try {
      await _recorder.start();
      var recording = await _recorder.current(channel: 0);
      setState(() {
        _current = recording;
      });

      const tick = const Duration(milliseconds: 50);
      new Timer.periodic(tick, (Timer t) async {
        if (_currentStatus == RecordingStatus.Stopped) {
          t.cancel();
        }

        var current = await _recorder.current(channel: 0);
        setState(() {
          _current = current;
          _currentStatus = _current.status;
        });
      });
    } catch (e) {
      print(e);
    }
  }

  _resume() async {
    await _recorder.resume();
    setState(() {});
  }

  _pause() async {
    await _recorder.pause();
    setState(() {});
  }

  _stop() async {
    var result = await _recorder.stop();
    print("Stop recording: ${result.path}");
    print("Stop recording: ${result.duration}");
    File file = widget.localFileSystem.file(result.path);
    print("File length: ${await file.length()}");
    setState(() {
      _current = result;
      _currentStatus = _current.status;
    });
  }

  Widget _buildText(RecordingStatus status) {
    var text = "";
    switch (_currentStatus) {
      case RecordingStatus.Initialized:
        {
          text = 'Start';
          break;
        }
      case RecordingStatus.Recording:
        {
          text = 'Pause';
          break;
        }
      case RecordingStatus.Paused:
        {
          text = 'Resume';
          break;
        }
      case RecordingStatus.Stopped:
        {
          text = 'Init';
          break;
        }
      default:
        break;
    }
    return Text(text, style: TextStyle(color: Colors.white));
  }

  void onPlayAudio() async {
    AudioPlayer audioPlayer = AudioPlayer();
    await audioPlayer.play(_current.path, isLocal: true);
  }
}