12345 you need to learn smali, and probably Java even before that. And learn how elements and components are loaded in smali. Then read documentation about from google (developer.android.com) about how to make your apps for android tv, and have dpad compatibility (which will be the same with flip phones). Decompile your app, reprogram the elements to be loaded in a dpad friendly way, add the necessary java code for controlling button presses, but make sure to write those functions in smali. Then recompile the app and sign it. Done!
No! I haven't done this ever!