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 P11 11.订阅者Subscriber的编程实现

如何实现一个订阅者

1. 初始化ROS节点；
2. 订阅需要的话题；
3. 循环等待话题消息，接收到消息后进入回调函数；
4. 在回调函数中完成消息处理。

C++

编写程序

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

/***********************************************************************
Copyright 2020 GuYueHome (www.guyuehome.com).
***********************************************************************//*** 该例程将订阅/turtle1/pose话题，消息类型turtlesim::Pose*/#include <ros/ros.h>
#include "turtlesim/Pose.h"// 接收到订阅的消息后，会进入消息回调函数
void poseCallback(const turtlesim::Pose::ConstPtr& msg)
{// 将接收到的消息打印出来ROS_INFO("Turtle pose: x:%0.6f, y:%0.6f", msg->x, msg->y);
}int main(int argc, char **argv)
{// 初始化ROS节点ros::init(argc, argv, "pose_subscriber");// 创建节点句柄ros::NodeHandle n;// 创建一个Subscriber，订阅名为/turtle1/pose的topic，注册回调函数poseCallbackros::Subscriber pose_sub = n.subscribe("/turtle1/pose", 10, poseCallback);// 循环等待回调函数ros::spin();return 0;
}

配置CMakeLists.txt

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

在Build内，Install前加入

add_executable(pose_subscriber src/pose_subscriber.cpp)
target_link_libraries(pose_subscriber ${catkin_LIBRARIES})

编译并运行发布者

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 turtlesim turtlesim_node
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic velocity_publisher# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic pose_subscriber# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rqt_graph

python

创建并编写脚本

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

#!/usr/bin/env python
# -*- coding: utf-8 -*-########################################################################
####          Copyright 2020 GuYueHome (www.guyuehome.com).          ###
######################################################################### 该例程将订阅/turtle1/pose话题，消息类型turtlesim::Poseimport rospy
from turtlesim.msg import Posedef poseCallback(msg):rospy.loginfo("Turtle pose: x:%0.6f, y:%0.6f", msg.x, msg.y)def pose_subscriber():# ROS节点初始化rospy.init_node('pose_subscriber', anonymous=True)# 创建一个Subscriber，订阅名为/turtle1/pose的topic，注册回调函数poseCallbackrospy.Subscriber("/turtle1/pose", Pose, poseCallback)# 循环等待回调函数rospy.spin()if __name__ == '__main__':pose_subscriber()

运行

sudo chmod +x ~/catkin_workspace/src/learning_topic/scripts/pose_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 turtlesim turtlesim_node
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic velocity_publisher.py# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_topic pose_subscriber.py# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rqt_graph