That's the entire issue, I've seen quite a lot of "sample" apps that do one thing (like nav bar, or fragments, or animations etc.)

But each of htem brings their own libraries, and don't explain what what's necessary and it's left to the user ot decide to how stitch all of this together.

Don't get me wrong...I'm happy for the demo apps (they had made my life a lot easier), but a production grade app is a whole different ballgame.