查询显示播放列表歌曲返回空？

Question

我试图找出一个MediaStore 查询，它将获取Playlist 的所有成员歌曲。但是，List 总是返回空而没有结果（即使在通知适配器之后）。这是我目前正在做的事情......

获取播放列表歌曲方法

ContentResolver musicResolver = getActivity().getContentResolver();
    Uri musicUri = MediaStore.Audio.Playlists.Members.getContentUri("external", playlistID);
    Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);

    if(musicCursor!=null && musicCursor.moveToFirst()){
        //get columns
        int idColumn = musicCursor.getColumnIndex
                (MediaStore.Audio.Playlists.Members.AUDIO_ID);
        int titleColumn = musicCursor.getColumnIndex
                (MediaStore.Audio.Playlists.Members.TITLE);
        int artistColumn = musicCursor.getColumnIndex
                (MediaStore.Audio.Playlists.Members.ARTIST);
        int albumColumn = musicCursor.getColumnIndex
                (MediaStore.Audio.Playlists.Members.ALBUM);
        int pathColumn = musicCursor.getColumnIndex
                (MediaStore.Audio.Playlists.Members.DATA);
        //add songs to list
        do {
            long thisId = musicCursor.getLong(idColumn);
            String thisTitle = musicCursor.getString(titleColumn);
            String thisArtist = musicCursor.getString(artistColumn);
            String thisAlbum = musicCursor.getString(albumColumn);
            String thisPath = musicCursor.getString(pathColumn);
            songList.add(new Song(thisId, thisTitle, thisArtist, thisAlbum, thisPath));
        }
        while (musicCursor.moveToNext());
    }
    musicCursor.close();

这就是我如何使用它的 ID 将值添加到播放列表中...

添加播放列表歌曲方法

public static void addToPlaylist(ContentResolver resolver, long audioId, String title, String artist, String album, String path) {

    String[] cols = new String[] {
            "count(*)"
    };
    Uri uri = MediaStore.Audio.Playlists.Members.getContentUri("external", playlistID);
    Cursor cur = resolver.query(uri, cols, null, null, null);
    cur.moveToFirst();
    cur.close();
    ContentValues values = new ContentValues();
    values.put(MediaStore.Audio.Playlists.Members.AUDIO_ID, audioId);
    values.put(MediaStore.Audio.Playlists.Members.TITLE, title);
    values.put(MediaStore.Audio.Playlists.Members.ARTIST, artist);
    values.put(MediaStore.Audio.Playlists.Members.ALBUM, album);
    values.put(MediaStore.Audio.Playlists.Members.DATA, path);
    resolver.insert(uri, values);
}

有什么建议吗？谢谢！

Answer 1

抱歉，我在度假时花了一点时间。 要添加到播放列表，您当然只需要 audio_id 和 play_order 和 playlist_id。下面的代码有 cursor 和 where 子句，因为这允许您添加多个轨道，但如果您已经拥有 audio_id，则不需要它

            ContentResolver resolver = context.getContentResolver();
    Uri exturi = MediaStore.Audio.Playlists.Members.getContentUri(
            "external", playlist_id);
    where = MediaStore.Audio.Media._ID + "=?";
    String[] whereVal = {music_id};

    Uri mediauri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor c = resolver.query(mediauri, projection, where, whereVal,
            null);

    if (c != null && c.moveToFirst()) {
        int idColumn = c.getColumnIndex(MediaStore.Audio.Media._ID);
        ContentValues values = new ContentValues();

        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
            String audio_id = c.getString(idColumn);
            values.put(MediaStore.Audio.Playlists.Members.PLAY_ORDER, base);
            values.put(MediaStore.Audio.Playlists.Members.AUDIO_ID, audio_id);
            resolver.insert(exturi, values);
            base++;
        }
        c.close();
    }

要获取播放列表中的所有曲目，我有以下代码：

         public Cursor getPlaylistTracks(Context context, Long playlist_id) {
    Uri newuri = MediaStore.Audio.Playlists.Members.getContentUri(
            "external", playlist_id);
    ContentResolver resolver = context.getContentResolver();
    String _id = MediaStore.Audio.Playlists.Members._ID;
    String audio_id = MediaStore.Audio.Playlists.Members.AUDIO_ID;
    String artist = MediaStore.Audio.Playlists.Members.ARTIST;
    String album = MediaStore.Audio.Playlists.Members.ALBUM;
    String album_id = MediaStore.Audio.Playlists.Members.ALBUM_ID;
    String title = MediaStore.Audio.Playlists.Members.TITLE;
    String duration = MediaStore.Audio.Playlists.Members.DURATION;
    String location = MediaStore.Audio.Playlists.Members.DATA;
    String composer = MediaStore.Audio.Playlists.Members.COMPOSER;
    String playorder = MediaStore.Audio.Playlists.Members.PLAY_ORDER;

    String date_modified = MediaStore.Audio.Playlists.Members.DATE_MODIFIED;
    String[] columns = {_id, audio_id, artist, album_id, album, title, duration,
            location, date_modified, playorder, composer};
    return resolver.query(newuri, columns, null, null, null);

}

希望对你有帮助