Standalone Calling - CometChat Docs

Overview

This section demonstrates how to implement calling functionality using only the CometChat Calls SDK, without requiring the Chat SDK. This is ideal for applications that need video/audio calling capabilities without the full chat infrastructure.

Before you begin, ensure you have completed the Calls SDK setup.

User Authentication

To start a call session, you need a user auth token. Since this implementation doesn’t use the Chat SDK, you’ll need to obtain the auth token via the CometChat REST API.

To understand user authentication in CometChat, see the User Auth documentation.

You can obtain the auth token using one of these REST API endpoints:

Create Auth Token — Creates a new auth token for a user
Get Auth Token — Retrieves an existing auth token

For testing or POC purposes, you can create an auth token directly from the CometChat Dashboard. Navigate to Users & Groups → Users, select a user, and click + Create Auth Token.

Store the auth token securely in your application for use when generating call tokens.

Generate Call Token

A call token is required for secure access to a call session. Each token is unique to a specific session and user combination, ensuring that only authorized users can join the call. You can generate the token just before starting the call, or generate and store it ahead of time based on your use case. Use the generateToken() method to create a call token:

Java
Kotlin

String sessionId = "UNIQUE_SESSION_ID"; // Generate a unique session ID
String userAuthToken = "USER_AUTH_TOKEN"; // Obtained from REST API

CometChatCalls.generateToken(sessionId, userAuthToken, new CometChatCalls.CallbackListener<GenerateToken>() {
    @Override
    public void onSuccess(GenerateToken generateToken) {
        // Use generateToken to start the session
    }

    @Override
    public void onError(CometChatException e) {
        Log.e(TAG, "Token generation failed: " + e.getMessage());
    }
});

val sessionId = "UNIQUE_SESSION_ID" // Generate a unique session ID
val userAuthToken = "USER_AUTH_TOKEN" // Obtained from REST API

CometChatCalls.generateToken(sessionId, userAuthToken, object : CometChatCalls.CallbackListener<GenerateToken>() {
    override fun onSuccess(generateToken: GenerateToken) {
        // Use generateToken to start the session
    }

    override fun onError(e: CometChatException) {
        Log.e(TAG, "Token generation failed: ${e.message}")
    }
})

Parameter	Description
`sessionId`	A unique session ID for the call. Generate this yourself or use a shared ID for participants to join the same call.
`userAuthToken`	The user auth token obtained from the CometChat REST API.

Start Call Session

Use the startSession() method to join a call session. This method requires a call token (generated in the previous step) and a CallSettings object that configures the call UI and behavior. The CallSettings class configures the call UI and behavior. Use CallSettingsBuilder to create a CallSettings instance with the following required parameters:

Parameter	Description
`activityContext`	The activity context where the call UI will be displayed
`videoContainer`	A `RelativeLayout` where the calling UI will be rendered
`callToken`	The `GenerateToken` object received from `generateToken()` onSuccess

Java
Kotlin

RelativeLayout videoContainer = findViewById(R.id.video_container);
Context activityContext = this;
GenerateToken callToken; // Received from generateToken() onSuccess

CallSettings callSettings = new CometChatCalls.CallSettingsBuilder(activityContext, videoContainer)
    .setDefaultLayoutEnable(true)
    .setIsAudioOnly(false)
    .build();

CometChatCalls.startSession(callToken, callSettings, new CometChatCalls.CallbackListener<String>() {
    @Override
    public void onSuccess(String s) {
        // Call session started successfully
    }

    @Override
    public void onError(CometChatException e) {
        // Handle error
    }
});

val videoContainer: RelativeLayout = findViewById(R.id.video_container)
val activityContext: Context = this
val callToken: GenerateToken // Received from generateToken() onSuccess

val callSettings = CometChatCalls.CallSettingsBuilder(activityContext, videoContainer)
    .setDefaultLayoutEnable(true)
    .setIsAudioOnly(false)
    .build()

CometChatCalls.startSession(callToken, callSettings, object : CometChatCalls.CallbackListener<String> {
    override fun onSuccess(s: String) {
        // Call session started successfully
    }

    override fun onError(e: CometChatException) {
        // Handle error
    }
})

Call Settings

Configure the call experience using the following CallSettingsBuilder methods:

Method	Description
`setDefaultLayoutEnable(boolean)`	Enables or disables the default call UI layout with built-in controls. `true` shows the default layout with end call, mute, video toggle buttons. `false` hides the button layout. Default: `true`
`setIsAudioOnly(boolean)`	Sets whether the call is audio-only or audio-video. `true` for audio-only, `false` for audio-video. Default: `false`
`setEventListener(CometChatCallsEventsListener)`	Sets the listener to receive call events. See Call Listeners for available callbacks.
`setMode(String)`	Sets the call UI layout mode. Available: `MODE_DEFAULT` (grid), `MODE_SPOTLIGHT` (active speaker), `MODE_SINGLE` (one participant). Default: `MODE_DEFAULT`
`setAvatarMode(String)`	Sets how avatars are displayed when video is off. Available: `AVATAR_MODE_CIRCLE`, `AVATAR_MODE_SQUARE`, `AVATAR_MODE_FULLSCREEN`. Default: `AVATAR_MODE_CIRCLE`
`setDefaultAudioMode(String)`	Sets the initial audio output device. Available: `AUDIO_MODE_SPEAKER`, `AUDIO_MODE_EARPIECE`, `AUDIO_MODE_BLUETOOTH`, `AUDIO_MODE_HEADPHONES`
`startWithAudioMuted(boolean)`	Starts the call with the microphone muted. Default: `false`
`startWithVideoMuted(boolean)`	Starts the call with the camera turned off. Default: `false`
`showEndCallButton(boolean)`	Shows or hides the end call button in the default layout. Default: `true`
`showSwitchCameraButton(boolean)`	Shows or hides the switch camera button (front/back). Default: `true`
`showMuteAudioButton(boolean)`	Shows or hides the mute audio button. Default: `true`
`showPauseVideoButton(boolean)`	Shows or hides the pause video button. Default: `true`
`showAudioModeButton(boolean)`	Shows or hides the audio mode selection button. Default: `true`
`showSwitchToVideoCallButton(boolean)`	Shows or hides the button to upgrade an audio call to video. Default: `true`
`showRecordingButton(boolean)`	Shows or hides the recording button. Default: `false`
`autoRecordOnCallStart(boolean)`	Automatically starts recording when the call begins. Default: `false`
`enableVideoTileClick(boolean)`	Enables or disables click interactions on video tiles in Spotlight mode. Default: `true`
`enableVideoTileDrag(boolean)`	Enables or disables drag functionality for video tiles in Spotlight mode. Default: `true`
`setMainVideoContainerSetting(MainVideoContainerSetting)`	Customizes the main video container. See Video View Customization.
`setIdleTimeoutPeriod(int)`	Sets idle timeout in seconds. Warning appears 60 seconds before auto-termination. Default: `180` seconds. v4.1.0+

Call Listeners

The CometChatCallsEventsListener interface provides real-time callbacks for call session events, including participant changes, call state updates, and error conditions. Register this listener in any activity or fragment where you need to respond to call events. Each listener requires a unique listenerId string. This ID is used to:

Prevent duplicate registrations — Re-registering with the same ID replaces the existing listener
Enable targeted removal — Remove specific listeners without affecting others

Java
Kotlin

private String listenerId = "UNIQUE_LISTENER_ID";

// Register listener (e.g., in onCreate or onResume)
CometChatCalls.addCallsEventListeners(listenerId, new CometChatCallsEventsListener() {
    @Override
    public void onCallEnded() {
        // Call ended, close the calling screen
    }

    @Override
    public void onSessionTimeout() {
        // Session timed out due to inactivity
    }

    @Override
    public void onCallEndButtonPressed() {
        // User pressed end call button
        CometChatCalls.endSession();
    }

    @Override
    public void onUserJoined(RTCUser user) {
        // A participant joined the call
    }

    @Override
    public void onUserLeft(RTCUser user) {
        // A participant left the call
    }

    @Override
    public void onUserListChanged(ArrayList<RTCUser> users) {
        // Participant list updated
    }

    @Override
    public void onAudioModeChanged(ArrayList<AudioMode> devices) {
        // Available audio devices changed
    }

    @Override
    public void onCallSwitchedToVideo(CallSwitchRequestInfo info) {
        // Call upgraded from audio to video
    }

    @Override
    public void onUserMuted(RTCMutedUser muteObj) {
        // A participant's mute state changed
    }

    @Override
    public void onRecordingToggled(RTCRecordingInfo info) {
        // Recording started or stopped
    }

    @Override
    public void onError(CometChatException ce) {
        // An error occurred
    }
});

// Unregister listener (e.g., in onDestroy or onPause)
CometChatCalls.removeCallsEventListeners(listenerId);

val listenerId = "UNIQUE_LISTENER_ID"

// Register listener (e.g., in onCreate or onResume)
CometChatCalls.addCallsEventListeners(listenerId, object : CometChatCallsEventsListener {
    override fun onCallEnded() {
        // Call ended, close the calling screen
    }

    override fun onSessionTimeout() {
        // Session timed out due to inactivity
    }

    override fun onCallEndButtonPressed() {
        // User pressed end call button
        CometChatCalls.endSession()
    }

    override fun onUserJoined(user: RTCUser) {
        // A participant joined the call
    }

    override fun onUserLeft(user: RTCUser) {
        // A participant left the call
    }

    override fun onUserListChanged(users: ArrayList<RTCUser>) {
        // Participant list updated
    }

    override fun onAudioModeChanged(devices: ArrayList<AudioMode?>?) {
        // Available audio devices changed
    }

    override fun onCallSwitchedToVideo(info: CallSwitchRequestInfo) {
        // Call upgraded from audio to video
    }

    override fun onUserMuted(muteObj: RTCMutedUser) {
        // A participant's mute state changed
    }

    override fun onRecordingToggled(info: RTCRecordingInfo) {
        // Recording started or stopped
    }

    override fun onError(ce: CometChatException?) {
        // An error occurred
    }
})

// Unregister listener (e.g., in onDestroy or onPause)
CometChatCalls.removeCallsEventListeners(listenerId)

Events

Event	Description
`onCallEnded()`	Invoked when the call session terminates for a 1:1 call. Both participants receive this callback. Only fires for calls with exactly 2 participants.
`onSessionTimeout()`	Invoked when the call is auto-terminated due to inactivity (default: 180 seconds). Warning appears 60 seconds before. v4.1.0+
`onCallEndButtonPressed()`	Invoked when the local user taps the end call button. Call `CometChatCalls.endSession()` to leave the session.
`onUserJoined(user: RTCUser)`	Invoked when a remote participant joins. The `user` contains UID, name, and avatar.
`onUserLeft(user: RTCUser)`	Invoked when a remote participant leaves the call session.
`onUserListChanged(users: ArrayList<RTCUser>)`	Invoked whenever the participant list changes (join or leave events).
`onAudioModeChanged(devices: ArrayList<AudioMode>)`	Invoked when available audio devices change (e.g., Bluetooth connected).
`onCallSwitchedToVideo(info: CallSwitchRequestInfo)`	Invoked when an audio call is upgraded to a video call.
`onUserMuted(muteObj: RTCMutedUser)`	Invoked when a participant’s mute state changes.
`onRecordingToggled(info: RTCRecordingInfo)`	Invoked when call recording starts or stops.
`onError(e: CometChatException)`	Invoked when an error occurs during the call session.

End Call Session

To end the call session and release all media resources (camera, microphone, network connections), call CometChatCalls.endSession() in the onCallEndButtonPressed() callback.

Java
Kotlin

// In onCallEndButtonPressed() callback
CometChatCalls.endSession();
// Close the calling screen

// In onCallEndButtonPressed() callback
CometChatCalls.endSession()
// Close the calling screen

Methods

These methods are available for performing custom actions during an active call session. Use them to build custom UI controls or implement specific behaviors based on your use case.

These methods can only be called when a call session is active.

Switch Camera

Toggles between the front and rear camera during a video call. Useful for allowing users to switch their camera view without leaving the call.

Java
Kotlin

CometChatCalls.switchCamera();

CometChatCalls.switchCamera()

Mute Audio

Controls the local audio stream transmission. When muted, other participants cannot hear the local user.

true — Mutes the microphone, stops transmitting audio
false — Unmutes the microphone, resumes audio transmission

Java
Kotlin

CometChatCalls.muteAudio(true);

CometChatCalls.muteAudio(true)

Pause Video

Controls the local video stream transmission. When paused, other participants see a frozen frame or avatar instead of live video.

true — Pauses the camera, stops transmitting video
false — Resumes the camera, continues video transmission

Java
Kotlin

CometChatCalls.pauseVideo(true);

CometChatCalls.pauseVideo(true)

Set Audio Mode

Routes the audio output to a specific device. Use this to let users choose between speaker, earpiece, or connected audio devices. Available modes:

CometChatCallsConstants.AUDIO_MODE_SPEAKER — Device speaker (loudspeaker)
CometChatCallsConstants.AUDIO_MODE_EARPIECE — Phone earpiece
CometChatCallsConstants.AUDIO_MODE_BLUETOOTH — Connected Bluetooth device
CometChatCallsConstants.AUDIO_MODE_HEADPHONES — Wired headphones

Java
Kotlin

String audioMode = CometChatCallsConstants.AUDIO_MODE_EARPIECE;
CometChatCalls.setAudioMode(audioMode);

val audioMode = CometChatCallsConstants.AUDIO_MODE_EARPIECE
CometChatCalls.setAudioMode(audioMode)

Enter PIP Mode

Enters Picture-in-Picture mode, rendering the call view in a small floating window. This allows users to multitask while staying on the call. Ensure your app has PIP support enabled in the manifest.

Java
Kotlin

CometChatCalls.enterPIPMode();

CometChatCalls.enterPIPMode()

Exit PIP Mode

Exits Picture-in-Picture mode and returns the call view to its original full-screen or embedded layout.

Java
Kotlin

CometChatCalls.exitPIPMode();

CometChatCalls.exitPIPMode()

Switch To Video Call

Upgrades an ongoing audio call to a video call. This enables the camera and starts transmitting video to other participants. The remote participant receives the onCallSwitchedToVideo() callback.

Java
Kotlin

CometChatCalls.switchToVideoCall();

CometChatCalls.switchToVideoCall()

Start Recording

Starts recording the call session. The recording is saved to the CometChat server and can be accessed later. All participants receive the onRecordingToggled() callback when recording starts.

Java
Kotlin

CometChatCalls.startRecording();

CometChatCalls.startRecording()

Stop Recording

Stops an ongoing call recording. All participants receive the onRecordingToggled() callback when recording stops.

Java
Kotlin

CometChatCalls.stopRecording();

CometChatCalls.stopRecording()

End Call

Terminates the current call session and releases all media resources (camera, microphone, network connections). After calling this method, the call view should be closed.

Java
Kotlin

CometChatCalls.endSession();

CometChatCalls.endSession()

​Overview

​User Authentication

​Generate Call Token

​Start Call Session

​Call Settings

​Call Listeners

​Events

​End Call Session

​Methods

​Switch Camera

​Mute Audio

​Pause Video

​Set Audio Mode

​Enter PIP Mode

​Exit PIP Mode

​Switch To Video Call

​Start Recording

​Stop Recording

​End Call

Overview

User Authentication

Generate Call Token

Start Call Session

Call Settings

Call Listeners

Events

End Call Session

Methods

Switch Camera

Mute Audio

Pause Video

Set Audio Mode

Enter PIP Mode

Exit PIP Mode

Switch To Video Call

Start Recording

Stop Recording

End Call