Android Video Calling Tutorial

This tutorial teaches you how to build a Zoom/Whatsapp-style video calling app.

• Calls run on Stream's global edge network for optimal latency & reliability.
• Permissions give you fine grained control over who can do what.
• Video quality and codecs are automatically optimized.
• Powered by Stream's Video Calling API.

1. Create a new project
2. Select Phone & Tablet -> Empty Activity
3. Name your project VideoCall.

Note that this tutorial was written using Android Studio Giraffe. Setup steps can vary slightly across Android Studio versions. We recommend using Android Studio Giraffe or newer.

The Stream Video SDK has two main artifacts:

• Core Client: io.getstream:stream-video-android-core - includes only the core part of the SDK.
• Compose UI Components: io.getstream:stream-video-android-ui-compose - includes the core + Compose UI components.

For this tutorial, we'll use the Compose UI Components.

Add the Video Compose SDK dependency to your app's build.gradle.kts file found in app/build.gradle.kts. If you're new to Android, note that there are 2 build.gradle.kts files, you want to open the one located in the app folder.

:exclamation: Replace <latest-version> with the version number indicated below (e.g. 0.5.7). Also, you can check the Releases page.

:exclamation: Make sure compileSdk (or compileSdkVersion if you're the older syntax) is set to 34 in your app/build.gradle.kts file.

:exclamation: Make sure you sync the project after doing these changes. Click on the Sync Now button above the file contents.

To keep this tutorial short and easy to understand we'll place all the code in MainActivity.kt. For a production app you'd want to initialize the client in your Application class or DI module. You'd also want to use a View Model.

Open MainActivity.kt and replace the MainActivity class with:

You can find below the import statements that are used throughout this tutorial. Paste them into your MainActivity.kt file to follow along easily.

To actually run this sample, we need a valid user token. The user token is typically generated by your server side API. When a user logs in to your app you return the user token that gives them access to the call.

To make this tutorial easier to follow we'll generate a user token for you. Please update REPLACE_WITH_API_KEY, REPLACE_WITH_TOKEN, REPLACE_WITH_USER_ID and REPLACE_WITH_CALL_ID with the actual values shown below:

Now when you run the sample app it will connect successfully. The text will say "Call <ID> has 1 participant" (yourself).

Let's review what we did in the code above.

Create a user. First we create a user object. You typically sync these users via a server side integration on your own backend. Alternatively, you can also use guest or anonymous users.

Initialize the Stream Video Client. Next we initialize the video client by passing the API Key, user and user token.

Create the call. After the user and client are created, we create a call.

Request runtime permissions. Before joining the call, we request camera and microphone runtime permissions to capture video and audio.

Review the permissions docs to learn more about how you can easily request permissions.

Join the call. We join the call in the onAllPermissionsGranted block.

As soon as you use call.join(), the connection for video & audio is setup.

Define the UI. Lastly, the UI is rendered by observing call.state (participants and connection states).

You'll find all relevant state for the call in call.state and call.state.participants. The documentation on Call state and Participant state explains this in further detail.

To make this a little more interactive, let's join the call from your browser.

On your Android device, you'll see the text update to 2 participants. Let's keep the browser tab open as you go through the tutorial.

In this next step we're going to render the local & remote participant video feeds.

In the MainActivity.kt file, replace the code inside VideoTheme with the example below:

Now when you run the app, you'll see your local video in a floating video element and the video from your browser. The end result should look somewhat like this:

Let's review the changes we made.

VideoRenderer is one of our primary low-level components.

It only displays the video and doesn't add any other UI elements. The video is lazily loaded, and only requested from the video infrastructure if you're actually displaying it. So if you have a video call with 200 participants, and you show only 10 of them, you'll only receive video for 10 participants. This is how software like Zoom and Google Meet make large calls work.

FloatingParticipantVideo renders a draggable display of your own video.

The above example showed how to use the call state object and Compose to build a basic video UI. For a production version of calling you'd want a few more UI elements:

• Indicators of when someone is speaking
• Quality of their network
• Layout support for >2 participants
• Labels for the participant names
• Call header and controls

Stream ships with several Compose components to make this easy. You can customize the components with theming, arguments and swapping parts of them. This is convenient if you want to quickly build a production ready calling experience for your app (and if you need more flexibility, many customers use the above low level approach to build a UI from scratch).

To render a full calling UI, we'll leverage the CallContent component. This includes sensible defaults for a call header, video grid, call controls, picture-in-picture, and everything that you need to build a video call screen.

Open MainActivity.kt, and update the code inside of VideoTheme to use the CallContent. The code will be a lot smaller than before since all UI logic is handled in the CallContent:

The result will be:

When you now run your app, you'll see a more polished video UI. It supports reactions, screensharing, active speaker detection, network quality indicators etc. The most commonly used UI components are:

• VideoRenderer: For rendering video and automatically requesting video tracks when needed. Most of the Video components are built on top of this.
• ParticipantVideo: The participant's video + some UI elements for network quality, reactions, speaking etc.
• ParticipantsGrid: A grid of participant video elements.
• FloatingParticipantVideo: A draggable version of the participant video. Typically used for your own video.
• ControlActions: A set of buttons for controlling your call, such as changing audio and video states.
• RingingCallContent: UI for displaying incoming and outgoing calls.

The full list of UI components is available in the docs.

You can customize the UI by:

• Building your own UI components (the most flexible, build anything).
• Mixing and matching with Stream's UI Components (speeds up how quickly you can build common video UIs).
• Theming (basic customization of colors, fonts etc).

The example below shows how to swap out the call controls for your own controls:

Stream's Video SDK provides fully polished UI components, allowing you to build a video call quickly and customize them. As you've seen before, you can implement a full complete video call screen with CallContent composable in Jetpack Compose. The CallContent composable consists of three major parts:

• appBarContent: Content is shown that calls information or additional actions.
• controlsContent: Content is shown that allows users to trigger different actions to control a joined call.
• videoContent: Content shown to be rendered when we're connected to a call successfully.

Theming gives you control over the colors and fonts.

Please let us know if you ran into any issues while building this video calling app with Compose. Our team is also happy to review your UI designs and offer recommendations on how to achieve it with our components.

To recap what we've learned about android video calling:

• You setup a call: (val call = client.call("default", "123"))
• The call type ("default" in the above case) controls which features are enabled and how permissions are setup
• When you join a call, realtime communication is setup for audio & video calling: (call.join())
• StateFlow objects in call.state and call.state.participants make it easy to build your own UI
• VideoRenderer is the low level component that renders video

We've used Stream's Video Calling API in this tutorial, which means calls run on a global edge network of video servers. By being closer to your users the latency and reliability of calls are better. The Compose SDK enables you to build in-app video calling, audio rooms and livestreaming in days.

We hope you've enjoyed this tutorial and please feel free to reach out if you have any suggestions or questions.

Final Thoughts

In this video app tutorial we built a fully functioning Android messaging app with our Android SDK component library. We also showed how easy it is to customize the behavior and the style of the Android video app components with minimal code changes.

Both the video SDK for Android and the API have plenty more features available to support more advanced use-cases.

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