（六）ROS使用C++类

一般模式头文件运行结果

学过C++类的都知道C++的类该怎么使用，对于ROS来说也是同样的做法。
在头文件中定义类：

定义私有和共有成员变量定义类的构造函数定义私有和共有成员函数

单独编写一个实现文件

包含头文件实现成员函数的原型 头文件

#ifndef EXAMPLE_ROS_CLASS_H_
#define EXAMPLE_ROS_CLASS_H_

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

class ExampleRosClass
{
private:
ExampleRosClass(ros::NodeHandle* nodehandle);
public:
ros::NodeHandle n;
ros::Publisher minimal_publisher;
ros::Subscriber minimal_subscriber;
ros::ServiceServer minimal_service;
double val_from_subscriber;
double val_to_remember;
void initializePublishers();
void initializeSubscribers();
void initializeServices();
void subscriberCallback(const std_msgs::Float32& message_holder);
bool serviceCallback(std_srvs::TriggerRequest& request,std_srvs::TriggerResponse& response);
};
#endif

#实现文件

#include 
ExampleRosClass::ExampleRosClass(ros::NodeHandle* nodehandle):n(*nodehandle)
{
	ROS_INFO("in class constructor of ExampleRosClass");
	initializePublishers();
	initializeSubscribers();
	initializeServices();
	val_to_remember=0.0;
}
void ExampleRosClass::initializePublishers()
{
	ROS_INFO("Initializing Publishers");
	minimal_publisher=n.advertise("example_class_output_topic",1,true);
}
void ExampleRosClass::initializeSubscribers()
{
	ROS_INFO("Initializing Subscribers");
	minimal_subscriber=n.subscribe("example_class_input_topic",1,&ExampleRosClass::subscriberCallback,this);
}
void ExampleRosClass::initializeServices()
{
	ROS_INFO("Initializing Services");
	minimal_service=n.advertiseService("example_minimal_service",&ExampleRosClass::serviceCallback,this);
}
void ExampleRosClass::subscriberCallback(const std_msgs::Float32& message_holder)
{
	val_from_subscriber=message_holder.data;
	ROS_INFO("myCallback activated: received value %f",val_from_subscriber);
	std_msgs::Float32 output_msg;
	val_to_remember += val_from_subscriber;
	output_msg.data=val_to_remember;
	minimal_publisher.publish(output_msg);
}
bool ExampleRosClass::serviceCallback(std_srvs::TriggerRequest& request,std_srvs::TriggerResponse& response)
{
	ROS_INFO("service callback activated");
	response.success = true;
	response.message = "here is a response string";
	return true;
}
int main(int argc,char **argv)
{
	ros::init(argc,argv,"exampleRosClass");
	ros::NodeHandle nh;
	ROS_INFO("main:instantiating an objecy of type ExampleRosClass");
	ExampleRosClass exampleRosClass(&nh);
	ROS_INFO("main: going into spin");
	ros::spin();
	return 0;
}

刚开始我还以为是要单独拿出头文件来编译，结果发现根本就不需要，只要在同一个目录下，然后直接调用就行了。

代码结构就不多讲了，就是一个很简单的订阅-发布通信方式，好吧还掺杂了一个服务客户端通信方式。