This demo is based on the great work done on https://github.com/Computician/janus-gateway-android
It adds an working example using the sip-Plugin
You have to replace
JANUSURI="ws://192.168.17.20:8188";
in MainActivity to run
For more details you can read a (German) blog article how we used the basic techniques used in the example: https://www.lamp-solutions.de/eigener-sprachdienst-mit-android-ueber-webrtc/