This section will provide information on how a complete calling workflow can be set up using CometChat. We’ve built the complete workflow to help your users make calls, receive calls as well as accept/reject calls. Let us assume Alex to be the call initiator and Bob is the receiver.
  1. Alex initiates the call to Bob using the initiateCall() method.
  2. Bob now has two choices:
    1. Accept the call from Alex using the acceptCall() method.
    2. Reject the call from Alex using the rejectCall(“rejected”) method passing the status as rejected.
  3. In the meantime, Alex has the option to cancel the call he initiated to Bob using the rejectCall(“cancelled”) method passing the status as cancelled.
  4. If Bob accepts the call from Alex, both Alex and Bob need to call the startCall() method. Alex in the onOutgoingCallAccepted() method of the CallListener and Bob in the success obtained from the acceptCall() method and both will be connected to each other.

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Initiate Call

The initiateCall() method sends a call request to a user or a group. 
private String receiverID = "UID";
private String receiverType = CometChatConstants.RECEIVER_TYPE_USER;
private String callType = CometChatConstants.CALL_TYPE_VIDEO;

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

CometChat.initiateCall(call, new CometChat.CallbackListener<Call>() {
  @Override
  public void onSuccess(Call call) {
    Log.d(TAG, "Call initiated successfully: " + call.toString());
  }
  
  @Override
  public void onError(CometChatException e) {
    Log.d(TAG, "Call initialization failed with exception: " + e.getMessage());
    
  }
});
This method takes an object of the Call class. The constructor for Call class takes the following parameters:
ParameterDescription
receiverIDThe UID or GUID of the recipient
receiverTypeThe type of the receiver viz. 1.CometChatConstants.RECEIVER_TYPE_USER 2.CometChatConstants.RECEIVER_TYPE_GROUP
callTypeThe type of the call viz. 1.CometChatConstants.CALL_TYPE_AUDIO 2.CometChatConstants.CALL_TYPE_VIDEO
On successful initialization, a Call object is returned with the details of the call including a unique session ID for the call.

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Receive Calls

For every activity you wish to receive the call events in, you need to register the CallListener listener using the addCallListener() method. 
private String listenerId = "UNIQUE_LISTENER_ID";

CometChat.addCallListener(listenerId, new CometChat.CallListener() {
  @Override
  public void onIncomingCallReceived(Call call) {
    Log.d(TAG, "Incoming call: " +
          call.toString());
  }

  @Override
  public void onOutgoingCallAccepted(Call call) {
    Log.d(TAG, "Outgoing call accepted: " +
          call.toString());
  }
  
  @Override
  public void onOutgoingCallRejected(Call call) {
    Log.d(TAG, "Outgoing call rejected: " +
          call.toString());
  }
  
  @Override
  public void onIncomingCallCancelled(Call call) {
    Log.d(TAG, "Incoming call cancelled: " +
          call.toString());
  }
});
ParametrerDescription
listenerIDAn ID that uniquely identifies that listener. We recommend using the activity or fragment name
We recommend you remove the listener once the activity or fragment is not in use. 
private String listenerId = "UNIQUE_LISTENER_ID";

CometChat.removeCallListener(listenerId);
As mentioned in the Overview section, Once the call is initiated, there are three options that can be possible:
  1. The receiver of the call accepts the call.
  2. The receiver of the call rejects the call.
  3. The initiator of the call cancels the call.
Please find below how these three scenarios can be implemented:

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Accept the Incoming Call

Once you have received an incoming call from a user or in any group, to accept the call using the acceptCall() method. 
private String sessionID = "SESSION_ID";

CometChat.acceptCall(sessionID, new CometChat.CallbackListener<Call>() {
  @Override
  public void onSuccess(Call call) {
    Log.d(TAG, "Call accepted successfully: " + call.toString());
  }

  public void onError(CometChatException e) {
    Log.d(TAG, "Call acceptance failed with exception: " + e.getMessage());
  }
});
ParameterDescription
sessionIDThe unique session ID available in the Call object

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Reject the Incoming Call

To reject the incoming call once it is received using the rejectCall() method. 
private String sessionID = "SESSION_ID";
private String status = CometChatConstants.CALL_STATUS_REJECTED;

CometChat.rejectCall(sessionID, status, new CometChat.CallbackListener<Call>() {
  @Override
  public void onSuccess(Call call) {
    Log.d(TAG, "Call rejected successfully with status: " +
          call.getCallStatus());
  }
  
  @Override
  public void onError(CometChatException e) {
    Log.d(TAG, "Call rejection failed with exception: " + e.getMessage());
  }
});
ParameterDescription
sessionIDThe unique session ID available in the Call object
statusReason for rejection of the call
Here the status needs to be set as CometChatConstants.CALL_STATUS_REJECTED as the call is being rejected by the receiver of the call.

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Cancel the Outgoing Call

In the case where the initiator wishes to cancel the call, use the same above rejectCall() method and just pass the status to the rejectCall() method as CometChatConstants.CALL_STATUS_CANCELLED

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Start a Call

Once the call request is sent and the receiver has accepted the call, both the initiator and the receiver need to call the startSession() method. Starting call session is same as Direct Call