I already knew the basic of android programming. now I want to build a offline multi-user chat application. I found peer-to-peer and Bluetooth are the most used techniques to communicate each other. I need to know,
Which one is easy to begin with among P2P and Bluetooth?
It depends on your previous skill and expertise. As I have seen that you have already managed to create an application for p2p communication via bluetooth, so of course it is easy to begin with bluetooth.
I already built a Bluetooth chat application using online tutorial. That method is a communicating between two endpoints. Is it possible to make it more than two?
Yes, it is possible. There are a lot of tutorials in the internet of connecting multiple bluetooth devices. Please check this SO answer.
However, chat application based on bluetooth is not a good approach. If this for your learning only, then from my point of view this is fine. If this is a professional project, then I would suggest you might consider looking into other options. Check this tutorial which uses Firebase as well. Using firebase for real time chat application will definitely serve your purpose.
