一、话题(Topic)通讯简介
二、话题案例
2.1、新建功能包
cd ~/ros_ws/src ros2 pkg create pkg_topic --build-type ament_python --dependencies rclpy --node-name publisher_demo
2.2、发布者实现
# 导入rclpy import rclpy from rclpy.node import Node # 导入String字符串消息 from std_msgs.msg import String class Topic_Publisher(Node): def __init__(self, name): super().__init__(name) # 创建发布者,使用create_publisher函数 # 传入参数分别是:话题数据类型、话题名称、消息队列长度 self.pub = self.create_publisher(String, "/topic_demo", 1) # 中断函数执行的间隔时间,中断处理函数 self.timer = self.create_timer(1, self.pub_msg) # 定义处理函数 def pub_msg(self): msg = String() msg.data = "Hello, I send a message" self.pub.publish(msg) #发布话题数据 def main(): rclpy.init() publisher_demo = Topic_Publisher("publisher_node") rclpy.spin(publisher_demo) publisher_demo.destroy_node() rclpy.shutdown()
2.3、订阅方实现
# 导入相关的库 import rclpy from rclpy.node import Node from std_msgs.msg import String class Topic_Subscriber(Node): def __init__(self, name): super().__init__(name) # 创建订阅者使用的是create_subscription # 参数分别是:话题数据类型、话题名称、回调函数名称,队列长度 self.sub = self.create_subscription(String, "/topic_demo", self.sub_callback, 1) # 回调函数 def sub_callback(self, msg): print("recv:" + msg.data) def main(): rclpy.init() subscriber_demo = Topic_Subscriber("subscriber_node") rclpy.spin(subscriber_demo) subscriber_demo.destroy_node() rclpy.shutdown()
2.4、编辑配置文件、编译工作空间
编译工作空间
cd ~/ros_ws colcon build --packages-select pkg_topic source install/setup.bash
2.5、运行程序
# 启动发布者节点 ros2 run pkg_topic publisher_demo # 启动订阅者节点 ros2 run pkg_topic subscriber_demo
运行发布者节点
运行订阅者节点