ros的类内消息订阅，消息同步封装

ros

1 Subscriber code

// ros_subscriber.h
#ifndef ROS_BRIDGE_ROS_SUBSCRIBER_H
#define ROS_BRIDGE_ROS_SUBSCRIBER_H
#include <ros/ros.h>
#include <std_msgs/String.h>
#include <sensor_msgs/Image.h>
#include <sensor_msgs/PointCloud2.h>
#include <message_filters/subscriber.h>
#include <message_filters/synchronizer.h>
#include <message_filters/sync_policies/approximate_time.h>
#include <string>
using message_filters::sync_policies::ApproximateTime;
class ImageCloudSubscriber {
//    typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::PointCloud2> ApproximateTimePolicy;
    using ApproximateTimePolicy = message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::PointCloud2>;
public:
    explicit ImageCloudSubscriber(ros::NodeHandle &nh, std::string img_topic) : m_nh(nh), m_img_topic(img_topic) {
        m_img_pub = m_nh.advertise<sensor_msgs::Image>("sub_convert_image", 10);
        m_img_msgpub = m_nh.advertise<sensor_msgs::Image>("msgsub_convert_image", 10);
        m_cloud_msgpub = m_nh.advertise<sensor_msgs::PointCloud2>("msgsub_convert_cloud", 10);
        //ros::Subscriber
        m_img_sub = m_nh.subscribe(m_img_topic, 10, &ImageCloudSubscriber::callBack, this);
        //message_filters::Subscriber
        m_img_msgsub = new message_filters::Subscriber<sensor_msgs::Image>(m_nh, m_img_topic, 1);//equivalent with ros::Subscriber
        m_img_msgsub->registerCallback(&ImageCloudSubscriber::msgFilterCallBack, this);
        //message_filters::Synchronizer
        m_cloud_msgsub = new message_filters::Subscriber<sensor_msgs::PointCloud2>(m_nh, "/velodyne_points", 10);
        m_sync = new message_filters::Synchronizer<ApproximateTimePolicy>(ApproximateTimePolicy(100), *m_img_msgsub, *m_cloud_msgsub);
        m_sync->registerCallback(boost::bind(&ImageCloudSubscriber::approximateCallback, this, _1, _2));
    }
    ~ImageCloudSubscriber() {
        delete m_img_msgsub;
        delete m_cloud_msgsub;
        delete m_sync;
    }
private:
    void callBack(const sensor_msgs::ImageConstPtr &msg) {
//        m_img_pub.publish(msg);
    }
    void msgFilterCallBack(const sensor_msgs::ImageConstPtr &msg) {
//        m_img_msgpub.publish(msg);
    }
    void approximateCallback(const sensor_msgs::ImageConstPtr&  img, const sensor_msgs::PointCloud2ConstPtr& cloud)
    {
        m_img_msgpub.publish(img);
        m_cloud_msgpub.publish(cloud);
    }
    ros::NodeHandle m_nh;
    std::string m_img_topic;
    ros::Subscriber m_img_sub;
    message_filters::Subscriber<sensor_msgs::Image> *m_img_msgsub;//use pointer is better
    message_filters::Subscriber<sensor_msgs::PointCloud2> * m_cloud_msgsub;
    message_filters::Synchronizer<ApproximateTimePolicy>* m_sync;
    ros::Publisher m_img_pub;
    ros::Publisher m_img_msgpub;
    ros::Publisher m_cloud_msgpub;
};
#endif //ROS_BRIDGE_ROS_SUBSCRIBER_H

2 main.cpp code

#include <ros/ros.h>
#include "ros_subscriber.h"
int main(int argc, char **argv) {
    ros::init(argc, argv, "test_node");
    ros::NodeHandle nh;
    ImageCloudSubscriber image_sub = ImageCloudSubscriber(nh, "/camera/image_raw");
    //multi-thread
    ros::AsyncSpinner spinner(1);
    spinner.start();
    while (ros::ok());
    //single thread
    //ros::spin();
    return 0;
}