平台：华硕 Thinker Edge R 瑞芯微 RK3399Pro
固件版本：Tinker_Edge_R-Debian-Stretch-V1.0.4-20200615

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记录自【古月居】古月·ROS入门21讲 | 一学就会的ROS机器人入门教程 —— 古月居GYH P12 12.话题消息的定义与使用

自定义话题消息

定义msg文件

cd ~/catkin_workspace/src/learning_topic
mkdir msg
nano ~/catkin_workspace/src/learning_topic/msg/Person.msg

string name
uint8  age
uint8  sexuint8 unknown = 0
uint8 male    = 1
uint8 female  = 2

在package.xml中添加功能包依赖

nano ~/catkin_workspace/src/learning_topic/package.xml

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

在CMakeLists.txt添加编译选项

...
find_package(... message_generation) 
...
add_message_files(FILES Person.msg)
generate_messages(DEPENDENCIES std_msgs)
...
catkin_package(... message_runtime)
...

nano ~/catkin_workspace/src/learning_topic/CMakeLists.txt

编译

cd ~/catkin_workspace
catkin_make

结果

可在~/catkin_workspace/devel/include/learning_topic下看到生成的Person.h

使用

C++

编写程序

person_publisher.cpp

nano ~/catkin_workspace/src/learning_topic/src/person_publisher.cpp

/***********************************************************************
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，消息类型为learning_topic::Person，队列长度10ros::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;
}

person_subscriber.cpp

nano ~/catkin_workspace/src/learning_topic/src/person_subscriber.cpp

/***********************************************************************
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personInfoCallbackros::Subscriber person_info_sub = n.subscribe("/person_info", 10, personInfoCallback);// 循环等待回调函数ros::spin();return 0;
}

配置CMakeLists.txt

nano ~/catkin_workspace/src/learning_topic/CMakeLists.txt

添加

add_executable(person_publisher src/person_publisher.cpp)
target_link_libraries(person_publisher ${catkin_LIBRARIES})
add_dependencies(person_publisher ${PROJECT_NAME}_generate_messages_cpp)add_executable(person_subscriber src/person_subscriber.cpp)
target_link_libraries(person_subscriber ${catkin_LIBRARIES})
add_dependencies(person_subscriber ${PROJECT_NAME}_generate_messages_cpp)

1. 设置需要编译的代码和生成的可执行文件；
2. 设置链接库；
3. 添加依赖项。
   

编译并运行

cd ~/catkin_workspace
catkin_make# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
roscore
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic person_publisher
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic person_subscriber# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rqt_graph

python

编写程序

person_publisher.py

nano ~/catkin_workspace/src/learning_topic/scripts/person_publisher.py

#!/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::Personimport rospy
from learning_topic.msg import Persondef 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10person_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

nano ~/catkin_workspace/src/learning_topic/scripts/person_subscriber.py

#!/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::Personimport rospy
from learning_topic.msg import Persondef 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personInfoCallbackrospy.Subscriber("/person_info", Person, personInfoCallback)# 循环等待回调函数rospy.spin()if __name__ == '__main__':person_subscriber()

运行

sudo chmod +x ~/catkin_workspace/src/learning_topic/scripts/person_publisher.py
sudo chmod +x ~/catkin_workspace/src/learning_topic/scripts/person_subscriber.py# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
roscore
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic person_publisher.py
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic person_subscriber.py# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rqt_graph