小编stu*_*ess的帖子

我正在尝试创建一个新的Playlist,使用Android ContentResolver,将添加到音乐播放器的播放列表中,但是当代码运行时,插入播放列表会返回null(对于Uri),当我检查音乐播放器的播放列表时,我的新Playlist条目不在那里.我怀疑insert()返回null 的原因是因为我没有正确创建播放列表.有人可以澄清如何动态创建新的播放列表,因为我的代码不起作用.(在我的搜索中,我找到了几种查询播放列表的方法,但实际上并没有创建新的播放列表)

这是我的代码......

    ContentResolver resolver = getActivity().getContentResolver();

    Uri playlists = MediaStore.Audio.Playlists.EXTERNAL_CONTENT_URI;

    Log.d(A.TAG, "Checking for existing playlist for " + chart.getName());
    Cursor c = resolver.query(playlists, new String[] {"*"}, null, null, null);
    long playlistId = 0;
    c.moveToFirst();
    do {
        String plname = c.getString(c.getColumnIndex(MediaStore.Audio.Playlists.NAME));
        if (plname.equalsIgnoreCase(chart.getName())) {
            playlistId = c.getLong(c.getColumnIndex(MediaStore.Audio.Playlists._ID));
            break;
        }
    } while (c.moveToNext());
    c.close();

    if (playlistId!=0) {
        Uri deleteUri = ContentUris.withAppendedId(playlists, playlistId);
        Log.d(A.TAG, "REMOVING Existing Playlist: " + playlistId);

        // delete …