This project originally started as a Java application, from which I used my basic knowledge of Android to adapt that project to Android. I learned a lot and I continue to develop for it to learn new things about Android, such as new libraries or new languages such as Kotlin.
Before when I initially did the Java app to Android, the code was a mess, and eventually I was able to separate a lot of the business logic from the actual Minesweeper model. I did that separating when I was converting the codebase to Kotlin as I was already doing a lot of changes, I thought I might as well do it then.