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自定义消息

1.定义msg文件

功能包下新建 msg 目录，添加文件 Person.msg

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string name
uint16 age
float64 height

2.编辑配置文件

package.xml中添加编译依赖与执行依赖

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

CMakeLists.txt编辑 msg 相关配置

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find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
  message_generation
)
# 需要加入 message_generation,必须有 std_msgs

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## 配置 msg 源文件
add_message_files(
  FILES
  Person.msg
)

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# 生成消息时依赖于 std_msgs
generate_messages(
  DEPENDENCIES
  std_msgs
)

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#执行时依赖
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES demo02_talker_listener
  CATKIN_DEPENDS roscpp rospy std_msgs message_runtime
#  DEPENDS system_lib
)

C++ 需要调用的中间文件(…/工作空间/devel/include/包名/xxx.h)

Python 需要调用的中间文件(…/工作空间/devel/lib/python3/dist-packages/包名/msg)

后续调用相关 msg 时，是从这些中间文件调用的

cpp实现

vscode配置

将前面生成的 head 文件路径配置进 c_cpp_properties.json 的 includepath属性:

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"includePath": [
                "/opt/ros/noetic/include/**",
                "/usr/include/**",
                "/xxx/yyy工作空间/devel/include/**" //配置 head 文件的路径 
            ],

发布方

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/*
    需求: 循环发布人的信息

*/

#include "ros/ros.h"
#include "demo02_talker_listener/Person.h"

int main(int argc, char *argv[])
{
    setlocale(LC_ALL,"");

    //1.初始化 ROS 节点
    ros::init(argc,argv,"talker_person");

    //2.创建 ROS 句柄
    ros::NodeHandle nh;

    //3.创建发布者对象
    ros::Publisher pub = nh.advertise<demo02_talker_listener::Person>("chatter_person",1000);

    //4.组织被发布的消息，编写发布逻辑并发布消息
    demo02_talker_listener::Person p;
    p.name = "sunwukong";
    p.age = 2000;
    p.height = 1.45;

    ros::Rate r(1);
    while (ros::ok())
    {
        pub.publish(p);
        p.age += 1;
        ROS_INFO("我叫:%s,今年%d岁,高%.2f米", p.name.c_str(), p.age, p.height);

        r.sleep();
        ros::spinOnce();
    }



    return 0;
}

订阅方

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/*
    需求: 订阅人的信息

*/

#include "ros/ros.h"
#include "demo02_talker_listener/Person.h"

void doPerson(const demo02_talker_listener::Person::ConstPtr& person_p){
    ROS_INFO("订阅的人信息:%s, %d, %.2f", person_p->name.c_str(), person_p->age, person_p->height);
}

int main(int argc, char *argv[])
{   
    setlocale(LC_ALL,"");

    //1.初始化 ROS 节点
    ros::init(argc,argv,"listener_person");
    //2.创建 ROS 句柄
    ros::NodeHandle nh;
    //3.创建订阅对象
    ros::Subscriber sub = nh.subscribe<demo02_talker_listener::Person>("chatter_person",10,doPerson);

    //4.回调函数中处理 person

    //5.ros::spin();
    ros::spin();    
    return 0;
}

配置 CMakeLists.txt

需要添加 add_dependencies 用以设置所依赖的消息相关的中间文件。

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add_executable(person_talker src/person_talker.cpp)
add_executable(person_listener src/person_listener.cpp)



add_dependencies(person_talker ${PROJECT_NAME}_generate_messages_cpp)
add_dependencies(person_listener ${PROJECT_NAME}_generate_messages_cpp)


target_link_libraries(person_talker
  ${catkin_LIBRARIES}
)
target_link_libraries(person_listener
  ${catkin_LIBRARIES}
)

python实现

vscode配置

为了方便代码提示以及误抛异常，需要先配置 vscode，将前面生成的 python 文件路径配置进 settings.json

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{
    "python.autoComplete.extraPaths": [
        "/opt/ros/noetic/lib/python3/dist-packages",
        "/xxx/yyy工作空间/devel/lib/python3/dist-packages"
    ]
}

发布方

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#! /usr/bin/env python
"""
    发布方:
        循环发送消息

"""
import rospy
from demo02_talker_listener.msg import Person


if __name__ == "__main__":
    #1.初始化 ROS 节点
    rospy.init_node("talker_person_p")
    #2.创建发布者对象
    pub = rospy.Publisher("chatter_person",Person,queue_size=10)
    #3.组织消息
    p = Person()
    p.name = "葫芦瓦"
    p.age = 18
    p.height = 0.75

    #4.编写消息发布逻辑
    rate = rospy.Rate(1)
    while not rospy.is_shutdown():
        pub.publish(p)  #发布消息
        rate.sleep()  #休眠
        rospy.loginfo("姓名:%s, 年龄:%d, 身高:%.2f",p.name, p.age, p.height)

订阅方

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 #! /usr/bin/env python
"""
    订阅方:
        订阅消息

"""
import rospy
from demo02_talker_listener.msg import Person

def doPerson(p):
    rospy.loginfo("接收到的人的信息:%s, %d, %.2f",p.name, p.age, p.height)


if __name__ == "__main__":
    #1.初始化节点
    rospy.init_node("listener_person_p")
    #2.创建订阅者对象
    sub = rospy.Subscriber("chatter_person",Person,doPerson,queue_size=10)
    rospy.spin() #4.循环

终端下进入 scripts 执行:chmod +x *.py

配置 CMakeLists.txt

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catkin_install_python(PROGRAMS
  scripts/talker_p.py
  scripts/listener_p.py
  scripts/person_talker.py
  scripts/person_listener.py
  DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
)