//! @brief Announce for a log file to be created.
// TODO: data_subscriber_srv should be named something like desktop_datalog_srv.
void log_chkbox_toggled (void) {
    if (log_file_chkbox->get_active()) {   // If checkbox is checked...
        if (log_file_chooser->get_filename() != "") {
            data_subscriber_srv.request.logfilename = log_file_chooser->get_filename();
        }
        data_subscriber_srv.request.isLogging = true;
    }
    else {
        log_file_chooser->unselect_all();
        data_subscriber_srv.request.isLogging = false;
    }

    datalog_client.call(data_subscriber_srv);   // Call the service with request and receive response.

    if (data_subscriber_srv.response.logfilename != "") {
        ROS_INFO("response.logfilename is %s.", data_subscriber_srv.response.logfilename.c_str());
        log_file_chooser->set_filename(data_subscriber_srv.response.logfilename);   // Set FileChooserButton filename to response.
    }
    else if (data_subscriber_srv.response.logfilename == "") {
        ROS_INFO("response.logfilename blank!");
    }
}