I started writing Android Apps because I enjoy coding and creating and seeing the fruits of my labor. Years ago, when I first started learning Java for fun, I stopped before I immersed myself into creating interfaces for the code I enjoyed writing. It was clear to me that creating the interfaces I could imagine was beyond my abilities and would take years of study and experience. So I reluctantly set Java aside and concentrated on other subjects that interested me.
Enter Android. I discovered that writing user interfaces was fairly easily so I could enjoyably code in Java behind the scenes instead of spending so much time on the interface with the end user.