I have no background or knowledge on this. I would like to make an app for performance engine building that has various pages with various formulas, unit conversions, tool lists, etc. What program do I use to make an app? I've seen Surge, Bevy, and Godot but those seem to be for games.
Edit: Thank you everyone for your helpful responses. Unfortunately I can only see the responses left on my post, not replys to top level responses. I think this is an instance problem and I'm trying to find out because I would love to see everyone's comments. All is working now
Android Studio is the primary toolkit for developing native android apps. If you have no background in programming, there are some more visual tools like Budibase (open source) or Softr (closed source), but you are likely to run into difficulty getting them to apply logic the way you'd like.
If you're a tinkerer, then honestly I'd look into learning more about Android Studio and Kotlin, the language most used these days for app development on Android.
As far as I'm aware, Samsung or Amazon are the only other real app "marketplaces". Most developers using Fdroid otherwise rely on donations or patreon for active development, depending on the nature of the app
Imo that's fine. It's also still the best tool for learning since it's the most widely supported one, and contains the greatest amount of documentation for working with android development. It costs nothing to use, and doesn't lock you into any kind of ecosystem you can't later migrate from.
Visual does sound nice but I'd rather go with something well used and stable. Is Android studio and Kotlin "open source"? I know what open source is but don't know how to make it that way or not. I've got a lot of learning to do clearly so I appreciate your help!
Android Studio is just the work environment for code and app development. You could continue on to publish all your code/work as an open source application through whichever means you choose during or after the fact.
The answers about getting started with Kotlin and Compose are good, but I'd like to offer for your consideration that your app may actually be more appropriate to build as a website. Food for thought.
I'd say it's kind of a good time to get into Android Development - Kotlin and Compose has made it highly pleasant and productive when compared to the days of Java and Views.
Godot can be used for any app, not just games. (Same goes for the other engines, I assume.) Though I can't say if you would have an easier time picking it up, rather than the traditional Java or Kotlin route.