1. 读取单个话题

1.1. 核心代码

   // 获取名为"my_topic"的话题的迭代器
  rosbag::View view(bag, rosbag::TopicQuery("my_topic"));

1.2. 完整示例

#include <ros/ros.h>
#include <rosbag/bag.h>
#include <std_msgs/String.h>
 
int main(int argc, char** argv)
{
  // 初始化ROS节点
  ros::init(argc, argv, "play_bag_node");
  ros::NodeHandle nh;
 
  // 创建ROSbag对象，打开bag文件
  rosbag::Bag bag;
  bag.open("example.bag", rosbag::bagmode::Read);
 
  // 获取名为"my_topic"的话题的迭代器
  rosbag::View view(bag, rosbag::TopicQuery("my_topic"));
 
  // 循环遍历话题中的所有消息
  for (rosbag::View::iterator it = view.begin(); it != view.end(); ++it)
  {
    // 转换消息类型
    std_msgs::String::ConstPtr msg = it->instantiate<std_msgs::String>();
 
    if (msg != NULL)
    {
      // 打印消息内容
      ROS_INFO("Message: %s", msg->data.c_str());
    }
  }
 
  // 关闭bag文件
  bag.close();
 
  return 0;
}

2. 读取多个话题

2.1. 核心代码

 // 获取三个话题的迭代器
  rosbag::View view(bag, rosbag::TopicQuery("my_string_topic") && rosbag::TopicQuery("my_image_topic") && rosbag::TopicQuery("my_laser_topic"));

2.2. 完整示例

#include <ros/ros.h>
#include <rosbag/bag.h>
#include <std_msgs/String.h>
#include <sensor_msgs/Image.h>
#include <sensor_msgs/LaserScan.h>
 
int main(int argc, char** argv)
{
  // 初始化ROS节点
  ros::init(argc, argv, "play_bag_node");
  ros::NodeHandle nh;
 
  // 创建ROSbag对象，打开bag文件
  rosbag::Bag bag;
  bag.open("example.bag", rosbag::bagmode::Read);
 
  // 获取三个话题的迭代器
  rosbag::View view(bag, rosbag::TopicQuery("my_string_topic") && rosbag::TopicQuery("my_image_topic") && rosbag::TopicQuery("my_laser_topic"));
 
  // 循环遍历话题中的所有消息
  for (rosbag::View::iterator it = view.begin(); it != view.end(); ++it)
   {
        // 从bag文件中读取消息
        const rosbag::MessageInstance& msg = *it;
        
        // 根据消息类型进行强制转换
        if (msg.isType<std_msgs::String>()) 
        {
            std_msgs::String::ConstPtr str_msg = msg.instantiate<std_msgs::String>();
            ROS_INFO_STREAM("String message: " << str_msg->data);
        }
        else if (msg.isType<sensor_msgs::Image>()) 
        {
            sensor_msgs::Image::ConstPtr img_msg = msg.instantiate<sensor_msgs::Image>();
            ROS_INFO_STREAM("Image message: " << img_msg->header.stamp);
            // 在此处添加处理Image消息的代码
        }
        else if (msg.isType<sensor_msgs::LaserScan>())
         {
            sensor_msgs::LaserScan::ConstPtr scan_msg = msg.instantiate<sensor_msgs::LaserScan>();
            ROS_INFO_STREAM("LaserScan message: " << scan_msg->header.stamp);
            // 在此处添加处理LaserScan消息的代码
        }
 
   }
 
    // 关闭bag文件
    bag.close();
    
    return 0;
    
}
 

3. 读取全部话题

3.1. 核心代码

rosbag::View view(bag);

或者

 rosbag::View view(bag, rosbag::TopicQuery(bag.getTopics()));

3.2. 读取方式1

    rosbag::Bag bag;
    bag.open(bagpath, rosbag::BagMode::Read);
    if(!bag.isOpen())
    {
        cout<<"can't open bag file!"<<endl;      
    }

    rosbag::View view(bag);
    rosbag::View::iterator it = view.begin();
    int iIndexTopic = 0;
    for(;it!= view.end(); it++)
    {
        if(it->getTopic() == "") continue;
        m[it->getTopic()] = 1;
 
       cout << "bag : " << it->getTopic() << it->getDataType() <<endl;
    }

3.3. 读取方式2

   int topic_num = view.getConnections().size();
   std::vector<std::string> tmp_topic;
    for (int i = 0; i < topic_num; i++)
    {
        tmp_topic.push_back(view.getConnections().at(i)->topic);
     }

3.4. 完整示例

#include <rosbag/bag.h>
#include <rosbag/view.h>
#include <ros/ros.h>
#include <string>
#include <vector>
// 定义一个函数，用于回放多个话题的数据
// 参数：
// - bag_filename: ROSbag文件名
// - topics: 一个包含多个话题名的vector，如果为空，则回放所有话题的数据
void playbackRosbag(const std::string& bag_filename, const std::vector<std::string>& topics = {})
 {
  	// 创建ROS节点
    // ros::NodeHandle nh("~");
    ros::NodeHandle nh;//sukai
 
  // 创建ROS话题发布器
  std::vector<ros::Publisher> pubs;
  for (const auto& topic : topics.empty() ? bag.getTopics() : topics)
  {
    if (topic == "/image") 
    {
      pubs.push_back(nh.advertise<sensor_msgs::Image>(topic, 1));
    }
    else if (topic == "/scan") 
    {
      pubs.push_back(nh.advertise<sensor_msgs::LaserScan>(topic, 1));
    }
    else if (topic == "/string") 
    {
      pubs.push_back(nh.advertise<std_msgs::String>(topic, 1));
    }
    else 
    {
      ROS_WARN_STREAM("Unknown topic: " << topic);
    }
  }
 
  // 回放数据
  // rosbag::Bag bag(bag_filename, rosbag::bagmode::Read);
  rosbag::Bag bag;//sukai
  bag.open(bag_filename, rosbag::bagmode::Read); //sukai
  
  rosbag::View view(bag, rosbag::TopicQuery(topics.empty() ? bag.getTopics() : topics));
  
  for (const auto& msg : view)
  {
    ros::Time timestamp = msg.getTime();
    std::string topic = msg.getTopic();
    if (topic == "/image") 
    {
      sensor_msgs::Image::ConstPtr image = msg.instantiate<sensor_msgs::Image>();
      if (image != nullptr) 
      {
        pubs[0].publish(image);
      }
    }
    else if (topic == "/scan") 
    {
      sensor_msgs::LaserScan::ConstPtr scan = msg.instantiate<sensor_msgs::LaserScan>();
      if (scan != nullptr) 
      {
        pubs[1].publish(scan);
      }
    }
    else if (topic == "/string") 
    {
      std_msgs::String::ConstPtr str = msg.instantiate<std_msgs::String>();
      if (str != nullptr) 
      {
        pubs[2].publish(str);
      }
    }
    else 
    {
      ROS_WARN_STREAM("Unknown topic: " << topic);
    }
  }
 
  // 关闭ROSbag文件
  bag.close();
 
  ROS_INFO_STREAM("Playback finished!");
}

主函数使用

int main(int argc, char** argv)
{
	ros::init(argc, argv, "rosbag_recorder_player");
  
	// 回放ROSbag文件中的所有话题数据
	playbackRosbag(bag_filename);
 
	// 回放ROSbag文件中的指定话题数据
	std::vectorstd::string playback_topics = {"/scan", "/string"};
	
	//playbackRosbag(bag_filename, playback_topics);
	playbackRosbag(bag_filename);

	return 0;
}