ros21讲学习-消息编写

建立msg文件夹，添加msg文件：Person.msg（首字母大写）

定义话题信息

string name
uint8  age
uint8  sex

uint8 unknown = 0
uint8 male    = 1
uint8 female  = 2

View Code

1.package.xml加入：

<build_depend>message_generation</build_depend>
<exec_depend>message_runtime</exec_depend>

2.cmakelist中添加黄色部分

#在开头

find_package(catkin REQUIRED COMPONENTS
geometry_msgs
roscpp
rospy
std_msgs
turtlesim
message_generation
)

#在ros message那块

add_message_files(
FILES
Person.msg
)

generate_messages(
DEPENDENCIES
std_msgs# std_msgs
)

#在 catkin specific configuration

catkin_package(

CATKIN_DEPENDS
message_runtime
)

3.编译

 cd ~/workspace/catkin_ws
 catkin_make

4.在~/workspace/catkin_ws/devel/include/learning_topic目录下生成了Person.h

----------------------------------------------------------------------------------------

5.发布话题，订阅话题

/***********************************************************************
Copyright 2020 GuYueHome (www.guyuehome.com).
***********************************************************************/

/**
 * 该例程将发布/person_info话题，自定义消息类型learning_topic::Person
 */
 
#include <ros/ros.h>
#include "learning_topic/Person.h"

int main(int argc, char **argv)
{
    // ROS节点初始化
    ros::init(argc, argv, "person_publisher");

    // 创建节点句柄
    ros::NodeHandle n;

    // 创建一个Publisher，发布名为/person_info的topic，消息类型learning_topic::Person，队列长度10
    ros::Publisher person_info_pub = n.advertise<learning_topic::Person>("/person_info", 10);

    // 设置循环的频率
    ros::Rate loop_rate(1);

    int count = 0;
    while (ros::ok())
    {
        // 初始化learning_topic::Person类型的消息
        learning_topic::Person person_msg;
        person_msg.name = "Tom";
        person_msg.age  = 18;
        person_msg.sex  = learning_topic::Person::male;
        // 发布消息

        person_info_pub.publish(person_msg);

           ROS_INFO("Publish Person Info: name:%s  age:%d  sex:%d", 
                  person_msg.name.c_str(), person_msg.age, person_msg.sex);

        // 按照循环频率延时
        loop_rate.sleep();
    }

    return 0;
}

View Code

/***********************************************************************
Copyright 2020 GuYueHome (www.guyuehome.com).
***********************************************************************/

/**
 * 该例程将订阅/person_info话题，自定义消息类型learning_topic::Person
 */
 
#include <ros/ros.h>
#include "learning_topic/Person.h"

// 接收到订阅的消息后，会进入消息回调函数
void personInfoCallback(const learning_topic::Person::ConstPtr& msg)
{
    // 将接收到的消息打印出来
    ROS_INFO("Subcribe Person Info: name:%s  age:%d  sex:%d", 
             msg->name.c_str(), msg->age, msg->sex);
}

int main(int argc, char **argv)
{
    // 初始化ROS节点
    ros::init(argc, argv, "person_subscriber");

    // 创建节点句柄
    ros::NodeHandle n;

    // 创建一个Subscriber，订阅名为/person_info的topic，注册回调函数personInfoCallback
    ros::Subscriber person_info_sub = n.subscribe("/person_info", 10, personInfoCallback);

    // 循环等待回调函数
    ros::spin();

    return 0;
}

View Code

6.编译，在cmakelist中加入

add_executable(person_publisher src/person_publisher.cpp)
add_executable(person_subscriber src/person_subscriber.cpp)

add_dependencies(person_publisher ${PROJECT_NAME}_generate_messages_cpp)
add_dependencies(person_subscriber ${PROJECT_NAME}_generate_messages_cpp)

target_link_libraries(person_publisher ${catkin_LIBRARIES})
target_link_libraries(person_subscriber ${catkin_LIBRARIES})

在终端

catkin_make

---------------------------------

7.执行

终端1：roscore
终端2：rosrun learning_topic person_publisher 
终端3：rosrun learning_topic person_subscriber

———————————————————————————————————————————————————————————————————————————————————————————————————Python———————————————————————————————————

———————————————————————————————————————————————————————————————————————————

　代码:

publisher

#!/usr/bin/env python
# -*- coding: utf-8 -*-

########################################################################
####          Copyright 2020 GuYueHome (www.guyuehome.com).          ###
########################################################################

# 该例程将发布/person_info话题，自定义消息类型learning_topic::Person

import rospy
from learning_topic.msg import Person

def velocity_publisher():
    # ROS节点初始化
    rospy.init_node('person_publisher', anonymous=True)

    # 创建一个Publisher，发布名为/person_info的topic，消息类型为learning_topic::Person，队列长度10
    person_info_pub = rospy.Publisher('/person_info', Person, queue_size=10)

    #设置循环的频率
    rate = rospy.Rate(10) 

    while not rospy.is_shutdown():
        # 初始化learning_topic::Person类型的消息
        person_msg = Person()
        person_msg.name = "Tom";
        person_msg.age  = 18;
        person_msg.sex  = Person.male;

        # 发布消息
        person_info_pub.publish(person_msg)
        rospy.loginfo("Publsh person message[%s, %d, %d]", 
                person_msg.name, person_msg.age, person_msg.sex)

        # 按照循环频率延时
        rate.sleep()

if __name__ == '__main__':
    try:
        velocity_publisher()
    except rospy.ROSInterruptException:
        pass

View Code

subscriber

#!/usr/bin/env python
# -*- coding: utf-8 -*-

########################################################################
####          Copyright 2020 GuYueHome (www.guyuehome.com).          ###
########################################################################

# 该例程将订阅/person_info话题，自定义消息类型learning_topic::Person

import rospy
from learning_topic.msg import Person

def personInfoCallback(msg):
    rospy.loginfo("Subcribe Person Info: name:%s  age:%d  sex:%d", 
             msg.name, msg.age, msg.sex)

def person_subscriber():
    # ROS节点初始化
    rospy.init_node('person_subscriber', anonymous=True)

    # 创建一个Subscriber，订阅名为/person_info的topic，注册回调函数personInfoCallback
    rospy.Subscriber("/person_info", Person, personInfoCallback)

    # 循环等待回调函数
    rospy.spin()

if __name__ == '__main__':
    person_subscriber()

View Code

执行方法：直接运行