Bulls and Cows

Bulls and Cows is a number guessing game.

Your goal is to guess a random 4 digit number with no repeating digits. Each guess will be scored a number of bulls and cows. Cows represent correct numbers in the wrong places, while bulls are correct numbers in the right place.

The implementation itself is minimal, with a single interface and no menus. Designed for Android devices with a resolution of at least 240x320, and scales well to my own device with a resolution of 720x1600.

Please comment any issues found or miscellaneous feedback, and I will do my best to respond quickly.