CallPage.dart

void _addAgoraEventHandlers() {
    AgoraRtcEngine.onError = (dynamic code) {
      setState(() {
        final info = 'onError: $code';
        _infoStrings.add(info);
      });
    };

    AgoraRtcEngine.onJoinChannelSuccess = (
      String channel,
      int uid,
      int elapsed,
    ) {
      setState(() {
        final info = 'onJoinChannel: $channel, uid: $uid';
        _infoStrings.add(info);
      });
    };

    AgoraRtcEngine.onLeaveChannel = () {
      setState(() {
        _infoStrings.add('onLeaveChannel');
        _users.clear();
      });
    };

    AgoraRtcEngine.onUserJoined = (int uid, int elapsed) {
      setState(() {
        final info = 'userJoined: $uid';
        _infoStrings.add(info);
        _users.add(uid);
      });
    };

    AgoraRtcEngine.onUserOffline = (int uid, int reason) {
      setState(() {
        final info = 'userOffline: $uid';
        _infoStrings.add(info);
        _users.remove(uid);
      });
    };

    AgoraRtcEngine.onFirstRemoteVideoFrame = (
      int uid,
      int width,
      int height,
      int elapsed,
    ) {
      setState(() {
        final info = 'firstRemoteVideo: $uid ${width}x $height';
        _infoStrings.add(info);
      });
    };
  }