Sample and resample value for a loop

I need to sample a 1x1 Mat that is converted to an int. When I make a loop like this while (grayVal <= 100){ Log.i("Mat Value", String.valueOf(grayVal)); } grayVal never changes, I know that I need to resample grayVal and pass it back into the loop. How would I go about doing this. edit: here is my code http://pastebin.com/4HA9H39f