Technologies WebRTCapp is a small elaboration that is part of my final degree project. This app aims to be a small video conference app created using mainly WebRTC technology. With it, you can make calls though a web socket connection. I already implemented something similar but easier connecting to a webSocket mocked server. You can find the code here and a brief post explaining the concept here


The app was built based on connecting to OpenVidu , an open source project that provides several libraries implementations to create video conference apps. For more info on whats the project about I highly recommend you to go and check the following links


Libraries in the project

WebRTC Library

You can find the code for the WebRTC library right on WebRTC's organization web. I wrote a briefly post on how WebRTC works internally that you can find here. On WebRTC's web you will find how to compile the binaries and generate the library but that for me wasn't that easy. So I have you solutions for you, this blog post that aims to explain how to compile that library.

ButterKnife Library

This library is really useful to bind views and it really helps us working with views in Android. The view can be injected directly on execution so you can directly use it right when you create the view. Link: ButterKnife

WebSocket Library

This library is a WebSocket client designed for Java. It implemented the protocol definition allowing us to use a WebSocket without having to implement the whole RFC. Link: WebSocket Library

How to download the project and run it

If you want to run the project locally on your computer you will need Android Studio with an emulator. You can clone the project using

   git clone https://github.com/sergiopaniego/WebRTCapp

opening it on Android Studio importing it and running it with the emulator that comes with it. As I mentioned above, the app is part of a final degree project and for that reason the address that comes built in the app points to https://demos.openvidu.io/basic-videoconference/. This URL hosts an OpenVidu's demo app that you can use to test that everything works as expected.

Development Environment

How did I developed the app? Tools I used

Android Studio 3.0.1

As my main IDE I’ve been using Android Studio 3.0.1, the latest version of the environment developed by Google and JetBrains to build Android apps. This IDE is built on JetBrain’s Intellij IDEA software and comes with all the tools needed to develop Android apps, from the native libraries including Kotlin to an emulator Android Studio's link.

Android Emulator

To develop the app, I needed an emulator to check that everything was running as expected. I chose a Pixel XL emulator with API 25 to run it. The emulator that comes integrated on the IDE is pretty good and there is no need to choose another one for the development I wanted.

Android device

An emulator is really helpful but a real device is what you really need to check that everything is going well. To help me with this part of the development, I used a Samsung Galaxy S6 device so it really helped me finding bugs.


Sonar is a tool that inspects your code to perform an static analysis that gives you a report on how your code health is. I have used it to try to keep my code clean Sonar Qube's web

App Permissions

The first time you open the app, it will ask you to give some permissions to the app. The permissions and the reason why we need the is the following:

Understanding the code

Scheme The code is divided in some packages to make the code easier to mantain.

In this part of the code is where the connecting happens, using the address that is built using the fields above.

Once the connection is established, you need to join a room, what it's make as follows

    Map<String, String> joinRoomParams = new HashMap<>();
    joinRoomParams.put("dataChannels", "false");
    joinRoomParams.put(JSONConstants.METADATA, "{\"clientData\": \"" + participantName + "\"}");
    joinRoomParams.put("secret", MY_SECRET);
    joinRoomParams.put("session", baseAddress + sessionName);
    joinRoomParams.put("token", token);
    sendJson(websocket, "joinRoom", joinRoomParams);

Using a JSON using RPC 2.0 with joinRoom method and the params that are shown here you can connect to the room Same process to leave the room, you just have to send

    webSocketAdapter.sendJson(webSocket, "leaveRoom", new HashMap<String, String>());

a JSON RPC 2.0 with the method leaveRoom and empty params.