Hey,

I'm using ROS Melodic on Ubuntu 18.04 and I'm trying to make a object orientated system. One of the classes I defined is a vision class.

Within this vision class I've defined a subscriber and a callback and some private variables. I've put them in a .h file. This .h file is used in my .cpp where my main is located. In my main I declare a vision object and a node handler. No matter what I do. Or how I try to assign the new values to my private variables, I'll always end up with only printing the standard object value. I've tried directly assigning it through this ->objectID = msg->data[0], without the this and also through making a setter. What would be a fix for this? My .h file

#pragma once
#include <ros/ros.h>
#include <std_msgs/Float32MultiArray.h>
using namespace std;

// Vision Class

class Vision
{
private:
    //ros variable
    ros::Subscriber vision_sub;

    // private variables
    char cameraID = 'None';
    int cameraXResolution = 720;
    int cameraYResolution = 1080;
    float objectID = 2;
    float xpersonCoordinate = 0;
    float ypersonCoordinate = 0;
    float zpersonCoordinate = 0;

public:   
    // constructors
    // Ros vision subscriber 
    Vision(ros::NodeHandle *nh)
    {  
        vision_sub = nh->subscribe("/VisionData", 1000, &Vision::callback_data, this);
    }

    // Member functions for visionClass

    //Setters
    void setCameraID(char cameraID)
    {
       this-> cameraID = cameraID; 
    }

    void setCameraResolution(int cameraXResolution, int cameraYResolution)
    {
        this-> cameraXResolution = cameraXResolution,
        this-> cameraYResolution = cameraYResolution;
    }

    void setObjectID(float objectID)
    {
        this-> objectID = objectID;
    }

    void setXYZCoordinates(float xpersonCoordinate, float ypersonCoordinate, float zpersonCoordinate)
    {
       this-> xpersonCoordinate = xpersonCoordinate,
       this-> ypersonCoordinate = ypersonCoordinate,
       this-> zpersonCoordinate = zpersonCoordinate;       
    }

     //Getters
    void getCameraResolution(int& cameraXResolution, int& cameraYResolution)
    {
        cameraXResolution = this-> cameraXResolution;
        cameraYResolution = this-> cameraYResolution;
    }

    void getObjectID(float& objectID)
    {
        objectID = this-> objectID;
    }

    void getXYZCoordinates(float& xpersonCoordinate, float& ypersonCoordinate, float& zpersonCoordinate)
    {
        xpersonCoordinate = this-> xpersonCoordinate;
        ypersonCoordinate = this-> ypersonCoordinate;
        zpersonCoordinate = this-> zpersonCoordinate;
    }
    //Callback for ROS
    void callback_data(const std_msgs::Float32MultiArray::ConstPtr& msg)
    {
        this -> objectID = msg->data[0];

   //    ROS_INFO("I heard: [%f]", msg->data[0]);
    }

};

My .cpp file

//includes
#include <ros/ros.h>
#include "visionClass.h"


////////////////////////////////////////////////////////////////////////////////
// namespaces
using namespace std;

////////////////////////////////////////////////////////////////////////////////
// testing
float testvalue = 1;

////////////////////////////////////////////////////////////////////////////////
// function prototypes


////////////////////////////////////////////////////////////////////////////////
// memberfunction run()

int main (int argc, char **argv)
{
        ros::init(argc, argv, "visionSystem");
        ros::NodeHandle nh;
        while(ros::ok())
        {
                Vision oakD(&nh);
                oakD.getObjectID(testvalue);
                ROS_INFO("From main I post:[%f]",testvalue);
                ros::spinOnce();
        }
}

////////////////////////////////////////////////////////////////////////////////
// functions