Question

我正在写一个Android音乐播放器，我在播放列表中找到下一首歌时遇到了问题。我有一首歌的两个值，播放列表ID（MediaStore.Audio.Playlists.Members.PLAYLIST_ID）和播放列表歌曲ID MediaStore.Audio.Playlists.Members._ID

这是相关的代码，尝试在当前歌曲之后的所有歌曲上获得光标：

    Uri qUri = MediaStore.Audio.Playlists.Members.getContentUri("external", playlistId);

    String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0 AND " + MediaStore.Audio.Playlists.Members._ID + " > " + songId +
            " AND "+ MediaStore.Audio.Playlists.Members.PLAYLIST_ID + " = " + playlistId;

    String[] projection = { MediaStore.Audio.Playlists.Members._ID };


    Cursor cursor;
    /* Execute query. */
    try{
        cursor = mContentResolver.query(qUri, projection, selection, null, null);
    } catch(SQLiteException s)
    {
        ReconApp.debugToast("SQLiteException in next track finder", ReconApp.ERROR_TOAST);
        s.printStackTrace();
        return -1;
    }

它捕获以下异常

10-14 14:24:08.207: ERROR/DatabaseUtils(1479): android.database.sqlite.SQLiteException: ambiguous column name: _id: , while compiling: SELECT audio_playlists_map._id AS _id FROM audio_playlists_map, audio WHERE (audio._id = audio_id AND playlist_id = 1) AND (is_music != 0 AND _id > 29 AND playlist_id = 1)

由于某种原因它会搜索两个表：audio_playlists_map，audio，这似乎是问题的根源。

是否可以找到具有这些值的下一首歌？它会使我的程序变得复杂，必须以不同的方式处理播放列表歌曲并存储其他一些值，我甚至不知道它会是什么，MediaStore.Audio.Playlists.Members.AUDIO_ID可能吗？

Answer 1

//你只能寻找和追加。试试这个

 String[] projection = new String[] {MediaStore.Audio.Playlists.Members.PLAYLIST_ID,
                MediaStore.Audio.Media.TITLE,
                MediaStore.Audio.Media.DATA,
                MediaStore.Audio.Media.ALBUM,
                MediaStore.Audio.Playlists.Members.AUDIO_ID};
            Uri contentUri = MediaStore.Audio.Playlists.Members.getContentUri("external", _playlistid);
            contentUri = contentUri.buildUpon().appendQueryParameter("limit", "1").build();
            Cursor playlistCursor = getContentResolver().query(contentUri,
                    projection,
                    null, null, MediaStore.Audio.Playlists.Members.PLAY_ORDER);

从Android播放列表中获取下一首/上一首歌

1 个答案: