Send a custom signal

Use signalingSendCustomSignal() to send small pieces of call-related application information to a call room, such as a raised-hand action, layout hint, or temporary state update. It is not suitable for chat content, large data, or files.

Send a signal

Both roomID and customInfo are required strings. Define a stable schema and serialize structured data as JSON.

JSONObject signal = new JSONObject();
signal.put("version", 1);
signal.put("eventID", eventID);
signal.put("type", "hand-raised");
signal.put("userID", currentUserID);
signal.put("sentAt", System.currentTimeMillis());

OpenIMClient.getInstance().signalingManager.signalingSendCustomSignal(
    new OnBase<String>() {
        @Override
        public void onSuccess(String result) {
            // The signaling request completed.
        }

        @Override
        public void onError(int code, String error) {
            // code and error describe the failure.
        }
    },
    roomID,
    signal.toString()
);

The success callback only confirms that the send request completed; it does not mean that other participants received or processed the signal. customInfo can include a protocol version and a unique eventID so receivers can identify duplicate messages. Custom signaling is intended for lightweight, temporary call negotiation; it does not transfer or retain large files, chat history, or durable state.

Receive a signal

When a custom signal arrives, OnSignalingListener.onReceiveCustomSignal receives CustomSignalingInfo. Confirm that it belongs to the active room and validate its format before updating the UI.

@Override
public void onReceiveCustomSignal(CustomSignalingInfo info) {
    // Check info.getRoomID(), then parse info.getCustomInfo() using your application protocol.
}

If your application needs to avoid duplicate processing, include a unique event ID in the custom signal and record processed events on the receiving side. Messages may not arrive in send order, so do not rely on arrival order to determine application state.

Register onReceiveCustomSignal together with the other call callbacks in the listener shown in Handle call events. SignalingManager retains only one listener; registering another one replaces the existing call callbacks.

Custom signaling is not a replayable record of durable state. After reconnecting, query the room or application data again when state needs to be reconciled.