How is answer choice calculated?

Question

Java

In general, there is a simple application for Android. Test type. And there you need to open all the answers (there are 16 of them, and there are 4 ^ 16 choices in total).
In general, I opened the apk. I opened the code ... and well, I just can not understand the logic. Not only is it extremely confusing in itself. So I still can not understand how the choice of option occurs. Do not kick strongly with your feet - I do not know java from the word "absolutely".
https://pastebin.com/E2jAFNJg
from line 2127, the answer is calculated by comparing three variables. So I can't understand - "how does countv get button presses"?