Joy_node How do I access buttons?[Solved]

edit

Hi I have x-box controller connected and topic echo's just fine.

I can even drive my bot around > teleop_twist_joy. So now I want to use the buttons on joy stick to move a servo and switch lights on/off.

I started a node witch compiles just fine but I am stuck on subscribing to joy sensor mseg. If I can get to the buttons info I would like to publish to "servo" topic to move servo (value from 0-180) ---later

For know just need to access joy_node.

 #include <ros/ros.h>
 #include <sensor_msgs/Joy.h>    // use to subscribe joy topic
 #include <std_msgs/UInt8.h>    //use to publish to servo topic


 void joyCallback(const sensor_msgs::Joy::ConstPtr& joy)
  {
   //   if (msg.buttons[0] == 1) {
   //        ROS_INFO("Button 0 pressed...");
   //}

//std::cout<<"axes: ["<< joy->axes[0] <<","<<joy->axes[1] <<","<<joy->axes[2] <<"<<"]"<<std::endl;
//std::cout<<"buttons: ["<<  joy->buttons[0]  <<","<< joy->buttons[1] <<ns[   <<"]"<<std::endl;
 }

 int main(int argc, char **argv)
 {
ros::init(argc, argv, "servo_controle_node");
ros::NodeHandle n("~");
ros::Rate loop_rate(50);
ros::Subscriber sub = n.subscribe("joy", 10, joyCallback);
ROS_INFO_ONCE("print out test");

//joyCallback(); //read joystick buttons

while (ros::ok())
{
    ros::spinOnce();
    loop_rate.sleep();
}
}

So if I can get the this= ros::Subscriber sub = n.subscribe("joy", 10, joyCallback); write then maybe I can access the buttons in the joyCallback function. Trolled the net with google and the "remote teleop node" or "simple plublisher/sebscriber node" not helping much

Update: Thanks Ravi Joshi your help apreciated. I solved it before I got back to update this post. so the new code....

#include <ros/ros.h>
#include <sensor_msgs/Joy.h> // use to subscribe joy topic
#include <std_msgs/UInt8.h>  //use to publish to servo topic

/*void stickCallback (const sensor_msgs::Joy::ConstPtr& msg)
  {
        for (unsigned i = 0; i < msg->axes.size(); ++i) 
            {
             ROS_INFO("Axis %d is now at position %f", i, msg->axes[i]);
             }
   }*/

 /*void buttonCallback (const sensor_msgs::Joy::ConstPtr& msg)
    {
         for (unsigned i = 0; i < msg->buttons.size(); ++i) {
             ROS_INFO("button %d is now at position %d", i, msg->buttons[i]);
             }
    }*/

 void servo_moveCallback(const sensor_msgs::Joy::ConstPtr &msg)  //while loop dont play nice
  {
                 //int a = msg->buttons[2];
                 int b = msg->buttons[1];
                 if (msg->buttons[2] == 1)
                     {
                       ROS_INFO("panning servo left publish");
                      }

                 else if ( b == 1  )
              {
              ROS_INFO("panning servo right publish");
              }
    }
    /***********************************************************************************
    created while sorting out left and right > keeping it around for up/down tilt
    **********************************************************************************/
 void servo2_moveCallback(const sensor_msgs::Joy::ConstPtr &msg)
  {
       if (msg->buttons[3] == 1)
     {
      ROS_INFO("tilting servo up publish");
      }

      else if ( msg->buttons[0]== 1  )
           {
            ROS_INFO("tilting servo down publish");
           }
 }
  /**********************************************************************************/
   int main(int argc, char **argv)
  {
  ros::init(argc, argv, "servo_controle_node");
  ros::NodeHandle nh;
 ros::Rate loop_rate(50);
 // ros::Subscriber sub = nh.subscribe("joy",10, stickCallback);    //test function to access joy sticks
 // ros::Subscriber sub2 = nh.subscribe("joy",10, buttonCallback);  //test function to access buttons
 ros::Subscriber sub3 = nh.subscribe("joy", 10, servo_moveCallback);
 ros::Subscriber sub4 = nh.subscribe("joy",10, servo2_moveCallback);

  ROS_INFO_ONCE("Servo_controle_node Started");

  while (ros::ok())
  {
    ros::spinOnce();
   loop_rate.sleep();
  }
 }

Ok, so first two functions (commented out ... (more)