Hello there,
I am an experienced programmer. I can do C/C++/Rust/assembly/Ruby/Perl/Python/ etc.. The language itself is not a barrier.
The barrier to me is that I have never coded a single web or android application. I guess it must be surprising but I am more of a low-level programmer in my job (I develop a compiler backend) and I never really had the opportunity or idea to work on an app.
What would be a good starting point for making an android application?
A quick search got me this: https://google-developer-training.github.io/android-developer-fundamentals-course-concepts-v2/unit-1-get-started/lesson-1-build-your-first-app/1-1-c-your-first-android-app/1-1-c-your-first-android-app.html
Would it be a good starting point?
Side note: my app will not have to interact with any service. If I were to code it as a command-line program, it would not take me more than a day or two. The actual app would involve (for now) no more than a text field, a button, some logic attached to it - the hard part for me being to choose a framework to build it, "upload it" to my phone and use it.
I've been using flutter + android studio and I'm enjoying it (as much as you can while making a mobile app). Android studio is a lot but it includes android emulators which is nice to test stuff on if you don't feel like getting your phone.
You'll need to install flutter (works on windows, mac, and linux), android studio (I think vscode also works?), and you can download a sample project, open it, build it, and run it. It's a great way to see how it works. Then you can create your own project and go from there. Flutter has a lot of packages which I would recommend at looking through (if your app is simple you might not need any of these though).
Once you build and run the app on your android phone, it's there and you can use it. You don't need to upload it to google play or anything else (unless you want to share it).