ROS 2 Publisher

Sample Code

Here is the code for creating a node that publishes strings to /robot_news at 2Hz.

PythonC++

#!/usr/bin/env python
import rclpy
from rclpy.node import Node
# import message type
from example_interfaces.msg import String

class RobotNewsStationNode(Node):
    def __init__(self):
        super().__init__("robot_news_station")

        # Create publisher with the proper message type
        self.publisher_ = self.create_publisher(String, "robot_news", 10)
        # Create timer to triger message at 2Hz
        self.timer_ = self.create_timer(0.5, self.publish_news)
        self.get_logger().info("Starting the robot news station")

    def publish_news(self):
        # Create massage payload
        msg = String()
        # Add 'Hello' as the data
        msg.data = "Hello"
        # Publish the data payload
        self.publisher_.publish(msg)


def main (args=None):
    rclpy.init(args=args)
    node = RobotNewsStationNode()
    rclpy.spin(node)
    rclpy.shutdown()


if __name__ == '__main__':
    main()

#include "rclcpp/rclcpp.hpp"
#include "example_interfaces/msg/string.hpp"

class RobotNewsStationNode : public rclcpp::Node
{
    public:
        RobotNewsStationNode() : Node("robot_news_station")
        {
            publisher_ = this->create_publisher<example_interfaces::msg::String>("robot_news", 10);
            timer_ = this->create_wall_timer(std::chrono::milliseconds(500),
                                            std::bind(&RobotNewsStationNode::publishNews, this));
            RCLCPP_INFO(this->get_logger(),"Robot News Station has been started.");
        }

private:
    void publishNews()
    {
        auto msg = example_interfaces::msg::String();
        msg.data = std::string("Hi, this is") + robot_name_ + std::string(" from the Robot News Station") ;
        publisher_->publish(msg);
    }

    std::string robot_name_;
    rclcpp::Publisher<example_interfaces::msg::String>::SharedPtr publisher_;
    rclcpp::TimerBase::SharedPtr timer_;
};

int main(int argc, char **argv)
{
    rclcpp::init(argc, argv);
    auto node = std::make_shared<RobotNewsStationNode>();
    rclcpp::spin(node);
    rclcpp::shutdown();
    return 0;
}