Join Session

CometChat Calls SDK v5 — Join Session (Flutter)

Overview

Join a call session using CometChatCalls.joinSession(). Returns a Widget that renders the call UI. Supports joining by session ID (token generated internally) or by a pre-generated CallToken.

Prerequisites

• Calls SDK initialized and user logged in
• A valid session ID (from Chat SDK's Call.sessionId or your backend)

Key Imports

import 'package:cometchat_calls_sdk/cometchat_calls_sdk.dart';

Implementation

Join with Session ID

final settings = SessionSettingsBuilder()
    .setTitle("Team Meeting")
    .startVideoPaused(false)
    .startAudioMuted(false)
    .build();

CometChatCalls.joinSession(
  sessionId: sessionId,
  sessionSettings: settings,
  onSuccess: (Widget? callWidget) {
    // Navigate to a screen that displays callWidget
    Navigator.push(context, MaterialPageRoute(
      builder: (_) => Scaffold(body: callWidget),
    ));
  },
  onError: (CometChatCallsException e) {
    debugPrint("Failed to join: ${e.message}");
  },
);

Join with Pre-Generated Call Token

// First generate a token
CometChatCalls.generateCallToken(sessionId,
  onSuccess: (CallToken token) {
    // Then join with the token
    CometChatCalls.joinSession(
      callToken: token,
      sessionSettings: settings,
      onSuccess: (Widget? callWidget) {
        // Display callWidget
      },
      onError: (e) => debugPrint("Join failed: ${e.message}"),
    );
  },
  onError: (e) => debugPrint("Token generation failed: ${e.message}"),
);

Voice Call vs Video Call

// Video call
final videoSettings = SessionSettingsBuilder()
    .setType(SessionType.video)
    .startVideoPaused(false)
    .startAudioMuted(false)
    .build();

// Voice call
final voiceSettings = SessionSettingsBuilder()
    .setType(SessionType.audio)
    .startVideoPaused(true)
    .startAudioMuted(false)
    .build();

Register Listeners After Joining

CometChatCalls.joinSession(
  sessionId: sessionId,
  sessionSettings: settings,
  onSuccess: (Widget? callWidget) {
    final session = CallSession.getInstance();
    session?.addSessionStatusListener(myStatusListener);
    session?.addButtonClickListener(myButtonListener);
    // Navigate to call screen
  },
  onError: (e) => debugPrint("Join failed: ${e.message}"),
);

Full Call Screen Example

class CallScreen extends StatefulWidget {
  final String sessionId;
  const CallScreen({super.key, required this.sessionId});

  @override
  State<CallScreen> createState() => _CallScreenState();
}

class _CallScreenState extends State<CallScreen>
    implements SessionStatusListeners, ButtonClickListeners {
  Widget? _callWidget;

  @override
  void initState() {
    super.initState();
    _joinSession();
  }

  void _joinSession() {
    final settings = SessionSettingsBuilder()
        .setTitle("CometChat Call")
        .startVideoPaused(false)
        .startAudioMuted(false)
        .build();

    CometChatCalls.joinSession(
      sessionId: widget.sessionId,
      sessionSettings: settings,
      onSuccess: (Widget? callWidget) {
        setState(() => _callWidget = callWidget);
        final session = CallSession.getInstance();
        session?.addSessionStatusListener(this);
        session?.addButtonClickListener(this);
      },
      onError: (e) {
        debugPrint("Join failed: ${e.message}");
        Navigator.pop(context);
      },
    );
  }

  @override
  void onSessionLeft() => Navigator.pop(context);

  @override
  void onConnectionClosed() => Navigator.pop(context);

  @override
  void onLeaveSessionButtonClicked() {
    CallSession.getInstance()?.leaveSession();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: _callWidget ?? const Center(child: CircularProgressIndicator()),
    );
  }
}

Gotchas

• joinSession returns a Widget? — embed it in your widget tree
• Provide exactly one of sessionId or callToken, not both
• All participants must use the same session ID to join the same call
• Call joinSession only after SDK is initialized and user is logged in
• Register listeners in the onSuccess callback of joinSession

Sample App Reference

• lib/screens/call_screen.dart — Call screen with Widget rendering
• lib/screens/home_screen.dart — Session ID input and call initiation