目录
1.在话题功能包的src目录下创建person_publisher.cpp
3.配置功能包的CMakeLists.txt中的编译规则,build栏中
实现内容:自定义话题内容,并且发布和订阅自定义话题中的信息
cd ~/catkin_ws/src/learning_topic mkdir msg cd msg touch Person.msg gedit Person.msg
Person.msg内容如下:
string name #字符串对象name uint8 sex uint8 age uint8 unknown = 0 #宏定义 uint8 male = 1 uint8 female = 2
注:定义姓名、性别、年龄
宏定义:未知、男、女
在话题功能包的package.xml中添加功能包的编译依赖和运行依赖
<build_depend>message_generation</build_depend> #动态产生message <exec_depend>message_runtime</exec_depend> #运行依赖
find_package(....... message_generation) add_message_files(FILES Person.msg) #将msg文件加入编译 generate_messages(DEPENDENCIES std_msgs)#依赖,在messages,services栏中加 catkin_package(...... message_runtime) #依赖若被注释要取消
cd ~/catkin_ws catkin_make
cd ~/catkin_ws/src/learning_topic/src touch person_publisher.cpp gedit person_publisher.cpp
person_publisher.cpp内容如下
//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; //定义Person对象 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; }
cd ~/catkin_ws/src/learning_topic/src touch person_subscriber.cpp gedit person_subscriber.cpp
person_subscriber.cpp内容如下:
//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; }
add_executable(person_publisher src/person_publisher.cpp) #运行 target_link_libraries(person_publisher ${catkin_LIBRARIES}) #库连接 add_dependencies(person_publisher ${PROJECT_NAME}_generate_messages_cpp)#连接依赖,与自定义消息连接 add_executable(person_subscriber src/person_subscriber.cpp) target_link_libraries(person_subscriber ${catkin_LIBRARIES}) add_dependencies(person_subscriber ${PROJECT_NAME}_generate_messages_cpp)
cd ~/catkin_ws catkin_make source ~/catkin_ws/devel/setup.bash
roscore source ~/catkin_ws/devel/setup.bash rosrun learning_topic person_publisher source ~/catkin_ws/devel/setup.bash rosrun learning_topic person_subscriber
注:1.订阅者可以会有一点延迟
2.当发布者和订阅者已经建立了连接,ros master就不再必要,ros master只负责为两者建立连接,若有其他连接才再需要
详细内容请看:ROS学习(四)发布者与订阅者
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