So I found AppGameKit earlier this month and I have created a couple of apps. My latest is a cab control that lets me control my model train layout from my phone!
The app communicates over TCPIP with my layout control software. Data on stations, trains, event lists, etc. are all exchanged in real-time without any hardcoded data that is specific to my layout. Images needed are cached and fetched fetched via http in real time if not already present. Commands to control the trains etc. are of course also sent over the TCPIP connection.
Shaders were new to me so I was very happy to see how powerful they are and I used it to manipulate static images that I have of the train tracks that get displayed as the train moves around the layout. The ambient light of the room is conveyed to teh app which then shades the image to match. The light from the locomotive headlights show up when one switches the headlights on too!
I used the percentage coord system.
The app has a number of screens and one can swipe left or right to flip between them or click on the 'tab' indicators along the bottom of the screen.
I created some genetic UI controls, a pull-down list that can be scrolled by swiping or mouse wheel, a button control, a radio button set - which is a lots of buttons, and it allows only one to be on and a number picker.
Some additional screen shots and earlier cab controls can be seen on my layout page at:
https://cabin-layout.mixmox.com/2021/11/android-cab-control.html