Develop Reference

Android Send files via Bluetooth programmatically

I have a java android app that list all nearby Bluetooth active devices, and the user can pair with a device.
I want to make the user when is paired with another device to send files or images via Bluetooth.
How can I achieve that in android (java)?

If you're doing this over classic Bluetooth, have a look at the following links:-
Bluetooth file transfer for Android
Android Bluetooth file sending
How can I send a file through bluetooth with Android devices
Android: Send image via Bluetooth
If you're doing this via Bluetooth Low Energy, have a look at the following links:-
The ultimate guide to Android BLE development
Bluetooth LE send string data between two devices
Transfer image through BLE in Android

How to automatically transfer files from USB OTG to internal storage or internal storage to USB OTG, when USB OTG connected in Android Studio?

I have developed an application which detects OTG USB using felhr85:UsbSerial library in Android. Now, I need to transfer specific files from Usb to phone and from phone to usb(automatically, when USB connected,detected). How can I do this, I haven't any idea. Please answer me with code.

How to configure a BLE device as a bridge to communicate from android app to a USB device?

I have a BLE device (BlueMode+S42). I have attached the BLE device to a phone via a USB cable. Now I want to communicate via an app I created that sends something to the other phone.
Android App (Bluetooth) -----> BLE device (USB cable) -----> Android phone
I can already connect and disconnect from the BLE device via the app. I can read the UUID's from the BLE Device too. So I already have the app that communicates with BLE, the problem now is to set the BLE device as a bridge to communicate from the app to the other phone.
The github project is available here (It works fine, don't look at the roughness of the code please :D): https://github.com/Dehma/BleConnectionProject.git
Edit:
Ok I did both connections and now I'm struggling with how to connect them toghether so the phones can communicate each other.

connecting two mobile phones over different network and then real time video streaming

I'm developing an application in which i want to connect two android phones over different networks and then want to stream user's video to one another with their own video e-g a user can see their own video and also the video of the friend who is connected with him over network.I want to do this thing without a server..Is it possible ??

I think this is possible see nanohttpd and you will have to connect both device using your app in same network and stream to a port listen to port

how to create live audio streaming between two android mobiles using socket programming..?

I am trying to develop an android app that will allow audio streaming between two android mobiles kind of audio conferencing by using socket programming.
what should i use for audio data transfer? i am using api 10

if you want to link inside a LAN then there is hope; however, if you want to connect through the internet then forget about it, NATs and CGNs and the likes won't let you (well, unless you'll provide a third-party relay server for your app).