How to get the number of tracks from a playlist?

Can someone tell me how to get the number of playlist members? I tried this but it doesn't work:

int PlayListCount = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Playlists._COUNT));

      

        
        
        
      

    

It throws this exception:

llegalStateException: Couldn't read row 0, col -1 from CursorWindow.
Make sure the Cursor is initialized correctly before accessing data from it.