i want to create an app for android and then for apple. or vice-versa. what program should i need to learn and how should i do it? i know c++ , java

I would suggest you take a look at React native especially if you have experience in web development

If you're going native most people do the iOS version first. In my experience it's at least 1.5x more time to make an Android port

Try out Ionic ;)

Oh I guess I ignored your comment about knowing c++ and java. Since you know java and want to go native, then starting with Android might be easier for you than iOS.
Depends also on your app and your target users where you want to start with.

its kinda like this app but with different categories and more interaction. but essentially is a communication app

so react native is better than lonic?

btw thanks for your time guys

@jorgecastillodp Haven't tried Ionic. But what I have heard and read, yes I think so.

i did some research and i guess native is faster.And smoother

@jorgecastillodp Yeah that's true in many cases. React native is different though. You are able to get native performance with React native.
But sure go ahead with whatever tech you like. I'm currently working on an hobby android project using java but I'm pretty sure I'll do my next app project using react native.

and to do react native you need to know Javascript right?. IM looking yp books about RN right now

@jorgecastillodp Yeah it's basically JS.
Check getpepperoni.com

@jorgecastillodp Since you know java, I think you should start with developing android apps using android studio, it will save your time from learning another language.
Also I think you are not familiar with mobile apps development with any platform, so that's a good reason you should start with android apps - java.

you are correct. i will definitely look into that aswell. thank you!

When u start to build UI with xml and java, u will miss the lightweight HTML, css, Javascript approach.

it's true, that in some cases native is faster than hybrid, when it comes to 3D animation and rendering.

But for simple "fetch-data-show" (FDS) apps ionic is easier to build and can be deployed on android, ios and windows with the same code.

ionic provides many "native" interfaces like native scrolling and animations.