ROS2-C++之消息的发布与订阅

参考博客：ROS 2 话题：使用C++进行发布与订阅

新建ROS包：testcpp

ros2 pkg create testcpp --build-type ament_cmake --dependencies rclcpp

如下：

发布

// 发布 ros2 run testcpp publisher_node
#include "rclcpp/rclcpp.hpp"
#include "std_msgs/msg/string.hpp"

using namespace std::chrono_literals;

class PublisherNode : public rclcpp::Node {
public:
    PublisherNode() : Node("publisher_node"), count_(0) {
        publisher_ = this->create_publisher<std_msgs::msg::String>("topic", 10);
        timer_ = this->create_wall_timer(
            500ms, std::bind(&PublisherNode::timer_callback, this));
    }

private:
    void timer_callback() {
        auto message = std_msgs::msg::String();
        message.data = "Hello, ROS 2: " + std::to_string(count_++);
        RCLCPP_INFO(this->get_logger(), "Publishing: '%s'", message.data.c_str());
        publisher_->publish(message);
    }

    rclcpp::Publisher<std_msgs::msg::String>::SharedPtr publisher_;
    rclcpp::TimerBase::SharedPtr timer_;
    size_t count_;
};

int main(int argc, char *argv[]) {
    rclcpp::init(argc, argv);
    rclcpp::spin(std::make_shared<PublisherNode>());
    rclcpp::shutdown();
    return 0;
}

订阅

// 订阅 ros2 run testcpp subscriber_node
#include "rclcpp/rclcpp.hpp"
#include "std_msgs/msg/string.hpp"

class SubscriberNode : public rclcpp::Node {
public:
    SubscriberNode() : Node("subscriber_node") {
        subscription_ = this->create_subscription<std_msgs::msg::String>(
            "topic", 10, std::bind(&SubscriberNode::topic_callback, this, std::placeholders::_1));
    }

private:
    void topic_callback(const std_msgs::msg::String::SharedPtr msg) const {
        RCLCPP_INFO(this->get_logger(), "I heard: '%s'", msg->data.c_str());
    }

    rclcpp::Subscription<std_msgs::msg::String>::SharedPtr subscription_;
};

int main(int argc, char *argv[]) {
    rclcpp::init(argc, argv);
    rclcpp::spin(std::make_shared<SubscriberNode>());
    rclcpp::shutdown();
    return 0;
}

修改CMakeLists.txt

添加如下内容：

find_package(std_msgs REQUIRED)

add_executable(publisher_node src/publisher_node.cpp)
ament_target_dependencies(publisher_node rclcpp std_msgs)

add_executable(subscriber_node src/subscriber_node.cpp)
ament_target_dependencies(subscriber_node rclcpp std_msgs)

install(TARGETS
  publisher_node
  subscriber_node
  DESTINATION lib/${PROJECT_NAME})

如下：