Android实现原生锁屏页面音乐控制

package com.yobbom.jiheboxplayer.service;

import android.os.Build;
import android.support.v4.media.MediaMetadataCompat;
import android.support.v4.media.session.MediaSessionCompat;
import android.support.v4.media.session.PlaybackStateCompat;

import com.yobbom.jiheboxplayer.model.Music;

/**
 * Created by Administrator on 2019/4/3.
 */

public class MediaSessionManager {
  private static final String TAG = "MediaSessionManager";
  private static final long MEDIA_SESSION_ACTIONS = PlaybackStateCompat.ACTION_PLAY
      | PlaybackStateCompat.ACTION_PAUSE
      | PlaybackStateCompat.ACTION_PLAY_PAUSE
      | PlaybackStateCompat.ACTION_SKIP_TO_NEXT
      | PlaybackStateCompat.ACTION_SKIP_TO_PREVIOUS
      | PlaybackStateCompat.ACTION_STOP
      | PlaybackStateCompat.ACTION_SEEK_TO;

  private PlayService playService;
  private MediaSessionCompat mediaSession;

  public static MediaSessionManager get(){
    return SingletonHolder.instance;
  }

  private static class SingletonHolder{
    private static MediaSessionManager instance = new MediaSessionManager();
  }

  private MediaSessionManager(){

  }

  //音乐的控制逻辑都在PlayService服务中，将service实例传递过来，与MediaSessionManager进行交互
  private void init(PlayService playService){
    this.playService = playService;
    setupMediaSession();
  }

  private void setupMediaSession(){
    mediaSession = new MediaSessionCompat(playService, TAG);
    //指明支持的按键信息类型
    mediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS | MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS);
    mediaSession.setCallback(callback);//设置监听回调
    mediaSession.setActive(true);//必须设置为true，这样才能开始接收各种信息
  }

  //点击控制按钮时，更新播放状态
  public void updatePlaybackState(){
    int state = (AudioPlayer.get().isPlaying() || AudioPlayer.get().isPreparing()) ? PlaybackStateCompat.STATE_PLAYING : PlaybackStateCompat.STATE_PAUSED;
    //第三个参数必须为1，否则锁屏上面显示的时长会有问题
    mediaSession.setPlaybackState(
        //监听的事件（播放，暂停，上一曲，下一曲）
        new PlaybackStateCompat.Builder()
          .setActions(MEDIA_SESSION_ACTIONS)
          .setState(state, AudioPlayer.get().getAudioPosition(), 1)
          .build());
  }

  //播放歌曲时，需要更新屏幕上的歌曲信息
  public void updateMetaData(Music music){
    if(music == null){
      mediaSession.setMetadata(null);
      return;
    }

    //Log.d(TAG, "parseMp3File名称: " + mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_TITLE));
    //Log.d(TAG, "parseMp3File专辑: " + mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUM));
    //Log.d(TAG, "parseMp3File歌手: " + mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ARTIST));
    //Log.d(TAG, "parseMp3File码率: " + mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_BITRATE));
    //Log.d(TAG, "parseMp3File时长: " + mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION));
    //Log.d(TAG, "parseMp3File类型: " + mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_MIMETYPE));

    MediaMetadataCompat.Builder metaData = new MediaMetadataCompat.Builder()
        .putString(MediaMetadataCompat.METADATA_KEY_TITLE, music.getTitle())
        .putString(MediaMetadataCompat.METADATA_KEY_ARTIST, music.getArtist())
        .putString(MediaMetadataCompat.METADATA_KEY_ALBUM, music.getAlbum())
        .putString(MediaMetadataCompat.METADATA_KEY_ALBUM_ARTIST, music.getArtist())
        .putLong(MediaMetadataCompat.METADATA_KEY_DURATION, music.getDuration())
        .putBitmap(MediaMetadataCompat.METADATA_KEY_ALBUM_ART, CoverLoader.get().loadThumb(music));

    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP){
      metaData.putLong(MediaMetadataCompat.METADATA_KEY_NUM_TRACKS, AppCache.get().getLocalMusicList().size());
    }

    mediaSession.setMetadata(metaData.build());
  }

  //初始化回调，用于监听锁屏界面上的按钮事件
  private MediaSessionCompat.Callback callback = new MediaSessionCompat.Callback() {
    @Override
    public void onPlay() {
      AudioPlayer.get().playPause();
    }

    @Override
    public void onPause() {
      AudioPlayer.get().playPause();
    }

    @Override
    public void onSkipToNext() {
      AudioPlayer.get().next();
    }

    @Override
    public void onSkipToPrevious() {
      AudioPlayer.get().prev();
    }

    @Override
    public void onStop() {
      AudioPlayer.get().stopPlayer();
    }

    @Override
    public void onSeekTo(long pos) {
      AudioPlayer.get().seekTo((int)pos);
    }
  };

}