Prawn is a great tool for generating PDFs. And the "prawn" gem works really well for Rails and Ruby. Getting started with might take some time, since it has a somewhat steep learning curve. Working with texts is the easiest.
If you have already started with Android TV development, you would know about BrowseSupportFragment. For the absolute beginners, to get started quickly with Android TV development, BrowseSupportFragment is the first thing that you would come across.