Converting Longitude & Latitude to X Y on a map with Calibration points

Here’s what worked for me, without so much bs.

int x =  (int) ((MAP_WIDTH/360.0) * (180 + lon));
int y =  (int) ((MAP_HEIGHT/180.0) * (90 - lat));

The lat,lon coordinates were given to me by Android devices. So they should be in the same standard used by all Google Earth/Map products.