MapView tile coordinates

Is it possible to determine the coordinates of the tiles that are visible in a MapView, relative to the first tile in the upper left corner of the entire map (including the invisible开发者_开发百科 part)? I can't seem to find a way to get the tile coordinates ...

I rewrote a script that can be found here which suits my needs: http://mapki.com/wiki/Lat/Lon_To_Tile