Android mediaplayer：艺术家与展示

在android Mediastore中查询SD卡中歌曲的艺术家名称。如果我们单击艺术家，它将显示特定艺术家的所有歌曲。我尝试过这样做，但它会显示SD卡中的所有歌曲。提前感谢

  private void music_grid(int ch) {
    System.gc();
    String[] musicproj ={MediaStore.Audio.Artists._ID,
                         MediaStore.Audio.Artists.ARTIST, 
                     MediaStore.Audio.Artists.NUMBER_OF_ALBUMS,
                     MediaStore.Audio.Artists.NUMBER_OF_TRACKS}

         final String sortOrder = ArtistColumns.ARTIST
                    + " COLLATE LOCALIZED ASC";
        Uri uri = MediaStore.Audio.Artists.EXTERNAL_CONTENT_URI;
        musiccursor = getBaseContext().getContentResolver().query(uri,
                    musicproj, null, null, null);

            count = musiccursor.getCount();
            gridmusic = (GridView) findViewById(R.id.gridmusic);
            Madapter = new MusicAdapter(getApplicationContext());
            gridmusic.setAdapter(Madapter);
            gridmusic.setOnItemClickListener(musicgridlistener1);

        }