liangchengyou / wow_english

  import 'package:audioplayers/audioplayers.dart';

  import 'package:flutter/cupertino.dart';

  import 'package:wow_english/common/extension/string_extension.dart';
  

  import 'log_util.dart';
  

  enum AudioPlayerUtilType {
    welcomeToWow('welcome_to_wow'),
    classTime('class_time'),
    gameTime('game_time'),
    musicTime('music_time'),
    readingTime('reading_time'),
    videoTime('video_time'),
    quizTime('quiz_time'),
    countWithMe('count_with_me_instrumental'),
    inMyTummy('in_my_tummy_instrumental'),
    touch('touch_instrumental');
  
    const AudioPlayerUtilType(this.path);
  
    final String path;
  }
  

  class AudioPlayerUtil extends WidgetsBindingObserver {

    static AudioPlayerUtil? _instance;

    late AudioPlayer _audioPlayer;

    late AudioPlayerUtilType currentType;

    bool _wasPlaying = false;

    static const TAG = "AudioPlayerUtil";

  
    // 私有构造函数
    AudioPlayerUtil._internal() {

      // 监听应用生命周期
      WidgetsBinding.instance.addObserver(this);
      _audioPlayer = AudioPlayer();
      _audioPlayer.onPlayerStateChanged.listen((event) async {

        if (event == PlayerState.completed) {
          // 播放结束再次播放
          if (currentType == AudioPlayerUtilType.inMyTummy) {
            AudioPlayerUtil.getInstance()
                .playAudio(AudioPlayerUtilType.inMyTummy);
          }
          if (currentType == AudioPlayerUtilType.countWithMe) {
            AudioPlayerUtil.getInstance()
                .playAudio(AudioPlayerUtilType.countWithMe);
          }
          if (currentType == AudioPlayerUtilType.welcomeToWow) {
            AudioPlayerUtil.getInstance().playAudio(AudioPlayerUtilType.touch);
          }
          if (currentType == AudioPlayerUtilType.touch) {
            AudioPlayerUtil.getInstance().playAudio(AudioPlayerUtilType.touch);
          }
        }
      });
    }
  
    static AudioPlayerUtil getInstance() {
      _instance ??= AudioPlayerUtil._internal();
      return _instance!;
    }
  
  // 播放音频
    Future<void> playAudio(AudioPlayerUtilType type) async {

      Log.d("$TAG playAudio $type");

      currentType = type;
      String path = type.path;

      await _audioPlayer.play(AssetSource(path.assetMp3), volume: 0.5);
      await _audioPlayer.onPlayerComplete.first;

    }
  
    // stop

    Future<void> stop() async {

      Log.d("$TAG stop _audioPlayer.state=${_audioPlayer.state}");

      await _audioPlayer.stop();

    }
  
    // pause

    Future<void> pause() async {

      Log.d("$TAG pause _audioPlayer.state=${_audioPlayer.state}");

      if (_audioPlayer.state == PlayerState.playing) {

        await _audioPlayer.pause();

      }
    }
  
    // resume

    Future<void> resume() async {

      Log.d("$TAG resume _audioPlayer.state=${_audioPlayer.state}");

      if (_audioPlayer.state == PlayerState.paused) {

        await _audioPlayer.resume();

      }
    }

  
    @override
    void didChangeAppLifecycleState(AppLifecycleState state) async {

      Log.d("$TAG didChangeAppLifecycleState appState=$state _wasPlaying=$_wasPlaying _audioPlayer.state=${_audioPlayer.state}");

      if (state == AppLifecycleState.paused) {
        if (_audioPlayer.state == PlayerState.playing) {
          _wasPlaying = true;
          await pause();
        };
      } else if (state == AppLifecycleState.resumed) {
        if (_wasPlaying == true) {
          _wasPlaying = false;
          await resume();
        }
      }
    }
  
    void dispose() {

      Log.d("$TAG dispose _audioPlayer.state=${_audioPlayer.state}");

      _audioPlayer.dispose();
      WidgetsBinding.instance.removeObserver(this);
    }

  }