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Implement incoming and outgoing call notifications with accept/reject functionality. Ringing enables real-time call signaling between users, allowing them to initiate calls and respond to incoming call requests.
Ringing functionality requires the CometChat Chat SDK for Flutter to be integrated alongside the Calls SDK. The Chat SDK handles call signaling (initiating, accepting, rejecting calls), while the Calls SDK manages the actual call session.

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How Ringing Works

The ringing flow involves two SDKs working together:
  1. Chat SDK - Handles call signaling (initiate, accept, reject, cancel)
  2. Calls SDK - Manages the actual call session once accepted

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Initiate a Call

Use the Chat SDK to initiate a call to a user or group: 
String receiverID = "USER_ID";
String receiverType = CometChatConstants.receiverTypeUser;
String callType = CometChatConstants.callTypeVideo;

Call call = Call(receiverID, receiverType, callType);

CometChat.initiateCall(call,
  onSuccess: (Call call) {
    debugPrint("Call initiated: ${call.sessionId}");
    // Show outgoing call UI
  },
  onError: (CometChatException e) {
    debugPrint("Call initiation failed: ${e.message}");
  },
);
ParameterTypeDescription
receiverIDStringUID of the user or GUID of the group to call
receiverTypeStringCometChatConstants.receiverTypeUser or receiverTypeGroup
callTypeStringCometChatConstants.callTypeVideo or callTypeAudio

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Listen for Incoming Calls

Register a call listener to receive incoming call notifications: 
String listenerID = "UNIQUE_LISTENER_ID";

CometChat.addCallListener(listenerID, CallListener(
  onIncomingCallReceived: (Call call) {
    debugPrint("Incoming call from: ${call.callInitiator?.name}");
    // Show incoming call UI with accept/reject options
  },
  onOutgoingCallAccepted: (Call call) {
    debugPrint("Call accepted, joining session...");
    joinCallSession(call.sessionId!);
  },
  onOutgoingCallRejected: (Call call) {
    debugPrint("Call rejected");
    // Dismiss outgoing call UI
  },
  onIncomingCallCancelled: (Call call) {
    debugPrint("Incoming call cancelled");
    // Dismiss incoming call UI
  },
  onCallEndedMessageReceived: (Call call) {
    debugPrint("Call ended");
  },
));
CallbackDescription
onIncomingCallReceivedA new incoming call is received
onOutgoingCallAcceptedThe receiver accepted your outgoing call
onOutgoingCallRejectedThe receiver rejected your outgoing call
onIncomingCallCancelledThe caller cancelled the incoming call
onCallEndedMessageReceivedThe call has ended
Remember to remove the call listener when it’s no longer needed to prevent memory leaks. In Flutter, you must manually remove listeners in your widget’s dispose() method:
CometChat.removeCallListener(listenerID);

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Accept a Call

When an incoming call is received, accept it using the Chat SDK: 
void acceptIncomingCall(String sessionId) {
  CometChat.acceptCall(sessionId,
    onSuccess: (Call call) {
      debugPrint("Call accepted");
      joinCallSession(call.sessionId!);
    },
    onError: (CometChatException e) {
      debugPrint("Accept call failed: ${e.message}");
    },
  );
}

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Reject a Call

Reject an incoming call: 
void rejectIncomingCall(String sessionId) {
  String status = CometChatConstants.callStatusRejected;

  CometChat.rejectCall(sessionId, status,
    onSuccess: (Call call) {
      debugPrint("Call rejected");
      // Dismiss incoming call UI
    },
    onError: (CometChatException e) {
      debugPrint("Reject call failed: ${e.message}");
    },
  );
}

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Cancel a Call

Cancel an outgoing call before it’s answered: 
void cancelOutgoingCall(String sessionId) {
  String status = CometChatConstants.callStatusCancelled;

  CometChat.rejectCall(sessionId, status,
    onSuccess: (Call call) {
      debugPrint("Call cancelled");
      // Dismiss outgoing call UI
    },
    onError: (CometChatException e) {
      debugPrint("Cancel call failed: ${e.message}");
    },
  );
}

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Join the Call Session

After accepting a call (or when your outgoing call is accepted), join the call session using the Calls SDK: 
void joinCallSession(String sessionId) {
  SessionSettings sessionSettings = CometChatCalls.SessionSettingsBuilder()
      .setType(SessionType.video)
      .build();

  CometChatCalls.joinSession(
    sessionId: sessionId,
    sessionSettings: sessionSettings,
    onSuccess: (Widget? callWidget) {
      debugPrint("Joined call session");
      // Place callWidget in your widget tree to render the call UI
    },
    onError: (CometChatCallsException e) {
      debugPrint("Failed to join: ${e.message}");
    },
  );
}
In Flutter, joinSession returns a Widget? through the onSuccess callback. You must place this widget in your Flutter widget tree to render the call UI. See Join Session for more details.

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End a Call

Properly ending a call requires coordination between both SDKs to ensure all participants are notified and call logs are recorded correctly.
Always call CometChat.endCall() when ending a call. This notifies the other participant and ensures the call is properly logged. Without this, the other user won’t know the call has ended and call logs may be incomplete.
When using the default call UI, listen for the end call button click using ButtonClickListener and call endCall(): 
CallSession? callSession = CallSession.getInstance();

// Listen for end call button click
callSession?.addButtonClickListener(ButtonClickListener(
  onLeaveSessionButtonClicked: () {
    endCall(currentSessionId);
  },
  // Other callbacks...
));

void endCall(String sessionId) {
  // 1. Leave the call session (Calls SDK)
  CallSession.getInstance()?.leaveSession();

  // 2. Notify other participants (Chat SDK)
  CometChat.endCall(sessionId,
    onSuccess: (Call call) {
      debugPrint("Call ended successfully");
      Navigator.of(context).pop();
    },
    onError: (CometChatException e) {
      debugPrint("End call failed: ${e.message}");
      Navigator.of(context).pop();
    },
  );
}
The other participant receives onCallEndedMessageReceived callback and should leave the session: 
CometChat.addCallListener(listenerID, CallListener(
  onCallEndedMessageReceived: (Call call) {
    CallSession.getInstance()?.leaveSession();
    Navigator.of(context).pop();
  },
  // Other callbacks...
));

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Call Status Values

StatusDescription
initiatedCall has been initiated but not yet answered
ongoingCall is currently in progress
busyReceiver is busy on another call
rejectedReceiver rejected the call
cancelledCaller cancelled before receiver answered
endedCall ended normally
missedReceiver didn’t answer in time
unansweredCall was not answered