从 MediaStore 查询播放列表

Question

我正在尝试从 MediaStore 查询设备中的播放列表。我已经关注了一个之前提出的问题，但我没有得到答案。

这就是我查询播放列表的方式

public void addToPlaylist(long playlistId, Context context,
                          ArrayList<Play> playlistTracks, String playlistName) {
    int count = getPlaylistSize(playlistId, context);
    Log.d("playlist size=", "" + count);

    ContentValues[] values = new ContentValues[playlistTracks.size()];
    for (int i = 0; i < playlistTracks.size(); i++) {
        values[i] = new ContentValues();
        values[i].put(MediaStore.Audio.Playlists.Members.PLAY_ORDER, i
                      + count + 1);
        values[i].put(MediaStore.Audio.Playlists.Members.AUDIO_ID,
                      playlistTracks.get(i).getId());
        values[i].put(MediaStore.Audio.Playlists.NAME, playlistName);
    }
    ContentResolver resolver = context.getContentResolver();
    Uri uri = MediaStore.Audio.Playlists.Members.getContentUri("external",
                                                               playlistId);
    int num = resolver.bulkInsert(uri, values); 
    Log.d("songs added=", "" + num); // added
    resolver.notifyChange(Uri.parse("content://media"), null);

}

private int getPlaylistSize(long playlistId, Context context)
{
    // TODO: Implement this method
    return 0;
}
public void retrieveAllPlaylists(Context context) {

    Uri tempPlaylistURI = MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI;

    final String idKey = MediaStore.Audio.Playlists._ID;
    final String nameKey = MediaStore.Audio.Playlists.NAME;


    final String[] columns = { idKey, nameKey };

    Cursor playListCursor = context.getContentResolver().query(
        tempPlaylistURI, columns, null, null, null);

    if (playListCursor != null) {
        Log.d("playlist cursor count=", "" + playListCursor.getCount());

        for (boolean hasItem = playListCursor.moveToFirst(); hasItem; hasItem = playListCursor
        .moveToNext()) {
            playlistName = playListCursor.getString(playListCursor
                                                    .getColumnIndex(nameKey));
            // noOfTracks = playListCursor.getInt(playListCursor
            // .getColumnIndex(tracksCountKey));
            Log.d(this.getClass().getName(), "playlistname=" + playlistName // returns only default playliststhe
                  + "tracks=" + noOfTracks);
            playlistModel.add(new Play(playlistName, noOfTracks));
        }


    }

}

我得到的只是一个空白屏幕。请指导我

Answer 1

创建播放列表的简单方法是：

            public void addnewPlaylist(Context context, String newplaylist) {
    ContentResolver resolver = context.getContentResolver();
    ContentValues values = new ContentValues(1);
    values.put(MediaStore.Audio.Playlists.NAME, newplaylist);
    resolver.insert(uri, values);

}

然后填充播放列表：

    public void addTrackToPlaylist(Context context, String audio_id,
    long playlist_id, int pos) {
    Uri newuri = MediaStore.Audio.Playlists.Members.getContentUri(
            "external", playlist_id);
    ContentResolver resolver = context.getContentResolver();
    ContentValues values = new ContentValues();
        values.put(MediaStore.Audio.Playlists.Members.PLAY_ORDER, pos);
        values.put(MediaStore.Audio.Playlists.Members.AUDIO_ID, audio_id);
        values.put(MediaStore.Audio.Playlists.Members.PLAYLIST_ID,
                playlist_id);
        resolver.insert(newuri, values);

}

查看您的代码，您没有构建正确的结构。播放列表不包含播放列表名称，仅包含 Playlist_id。

返回所有播放列表：

        public Cursor getandroidPlaylistcursor(Context context) {
    ContentResolver resolver = context.getContentResolver();
    final String id = MediaStore.Audio.Playlists._ID;
    final String name = MediaStore.Audio.Playlists.NAME;
    final String[] columns = { id, name };
    final String criteria = null
    return  resolver.query(uri, columns, criteria, null,
            name + " ASC");

}

Answer 2

填充数组的示例：

           Cursor cursor = plist.getPlaylistTracks(getActivity(), playlist_id);
     // replace with your own method to get cursor
    ArrayList<String> audio_ids = new ArrayList<String>();

    // build up the array with audio_id's
    int i = 0;
    if (cursor != null && cursor.moveToFirst()) {
        for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
            String audio_id = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Playlists.Members.AUDIO_ID));
            audio_ids.add(audio_id);
        }

确保在分配 audio_id（或您自己的变量）时，您使用获取光标时使用的正确 MediaStore uri。光标中的列名决定了您可以在这里获得什么。

Answer 3

回答来自 kh3e 的问题： 在处理播放列表和播放列表成员时

   public Uri get_audio_playlists_uri(){
    Uri uri_to_use = null;
    //     int bld = Build.VERSION.SDK_INT;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        uri_to_use = MediaStore.Audio.Playlists.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY);
    } else {
        uri_to_use = MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI;
    }
    return uri_to_use;
}

public Uri get_audio_playlist_members_uri(long playlist_id){

    Uri uri_to_use = null;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        uri_to_use   = MediaStore.Audio.Playlists.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY)
                .buildUpon()
                .appendEncodedPath(Long.toString(playlist_id))
                .appendEncodedPath("members")
                .build();
    } else {
        uri_to_use = MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI
                .buildUpon()
                .appendEncodedPath(Long.toString(playlist_id))
                .appendEncodedPath("members")
                .build();
    }
    return uri_to_use;
}