Android查询系统的音频（音乐播放器的核心）

 //查询系统的音频库
     public static List<MusicBean> getMusicInfo(Context context){
         List<MusicBean> musicList= new ArrayList<>();
         //查询音频数据库
         Cursor c = context.getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, MediaStore.Audio.Media.DURATION+">=?", new String[]{"20000"}, MediaStore.Audio.Media.DEFAULT_SORT_ORDER);

         while (c.moveToNext()){
            MusicBean musicBean=new MusicBean();
             musicBean.setTitle(c.getString(c.getColumnIndex(MediaStore.Audio.Media.TITLE)));
             musicBean.setName(c.getString(c.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME)));
             //对未知艺术家进行判断
             String singer = c.getString(c.getColumnIndex(MediaStore.Audio.Media.ARTIST));
             if(singer==null || "".equals(singer) || "<unknown>".equals(singer)){
                 singer = "未知艺术家";
             }
             musicBean.setSinger(singer);
             musicBean.setAlbum(c.getString(c.getColumnIndex(MediaStore.Audio.Media.ALBUM)));
             musicBean.setSize(c.getLong(c.getColumnIndex(MediaStore.Audio.Media.SIZE)));
             musicBean.setTime(c.getLong(c.getColumnIndex(MediaStore.Audio.Media.DURATION)));
             musicBean.setUrl(c.getString(c.getColumnIndex(MediaStore.Audio.Media.DATA)));
             musicList.add(musicBean);

         }
         //关闭游标，释放资源
         c.close();
         return musicList;
     }