Mobile Apps - Where to start?

I want to create some mobile apps. Data to come from a host, data to be acquired from the mobile device & (eventually) sent back to the host. Probably going to need local storage for when users don’t have internet access. Want to interact with functions on the mobile device e.g. GPS and handwriting, maybe barcode reading. Initial target is Android, but also interested in iOS.

I am a professional developer but not using any of these technologies currently, nor do I have time to learn competely new technologies. Java is out. HTML, CSS, XML aren’t an issue. I could probably cope with Javascript. I’m not impressed with the many ‘create apps - no coding’ ideas.

What are (all) the possible ways of doing this reasonably quickly & cheaply?
What should I be reading up on?

Thanks, in advance.

Hi, axe
In my opinion, sign up for Udemy’s Beginner Java Course , learn java from there first. Yes, to develop for android you must know Java. The, sign up for Adam Porter’s Android Development Course. (You might need to log in in order to not get a 404 error.). And that’s that. Good luck

If you don’t know object-oriented programming, I hear it is a steep learning curve to build mobile apps. In fact, if you were good with OOP, I hear it is a steep learning curve to build mobile apps.

Nothing like a bit of encouragement!