rostopic demo

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-  
import rospy
from hdw_driver.msg import update_file_msg

def talker():
    pub = rospy.Publisher(‘hdw_update‘,update_file_msg, queue_size=10)
    rospy.init_node(‘talker‘,anonymous=True)
    #rate = rospy.Rate(10) # 10hz

    mi = update_file_msg()
    mi.motor_board_file_name="/opt/xx/motor_board_file_name.rb"
    mi.power_board_file_name="/opt/xx/power_board_file_name.rb"
    mi.sensor_board_file_name="/opt/xx/sensor_board_file_name.rb"
    mi.imu_board_file_name="/opt/xx/imu_board_file_name.rb"

    mi.update_motor_board=True
    mi.update_power_board=True
    mi.update_sensor_board=True
    mi.update_imu_board=True
    pub.publish(mi)
    rospy.signal_shutdown("closed!")
 
if __name__ == ‘__main__‘:
    try:
        talker()
    except rospy.ROSInterruptException:
        pass

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-  

import rospy
from hdw_driver.msg import update_file_msg

def callback(data):
    rospy.loginfo(data)
    #回调函数 收到的参数.data是通信的数据 默认通过这样的 def callback(data) 取出data.data数据
    
def listener():

    # In ROS, nodes are uniquely named. If two nodes with the same
    # node are launched, the previous one is kicked off. The
    # anonymous=True flag means that rospy will choose a unique
    # name for our ‘listener‘ node so that multiple listeners can
    # run simultaneously.
    rospy.init_node(‘listener‘, anonymous=True)
    
    #启动节点同时为节点命名， 若anoymous为真则节点会自动补充名字，实际名字以 listener_322345等表示
    #若为假，则系统不会补充名字，采用用户命名。但是一次只能有一个同名节点，若后面有一个相同listener
    #名字的节点则后面的节点启动会注销前面的相同节点名。
    
    rospy.Subscriber("hdw_update", update_file_msg, callback)
    
    #启动订阅，订阅主题，及标准字符串格式，同时调用回调函数，当有数据时调用函数，取出数据
    
    # spin() simply keeps python from exiting until this node is stopped
    
    #循环程序
    rospy.spin()

if __name__ == ‘__main__‘:
    listener()