Say I want to make an app on my phone for personal use. How to begin?

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.