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Use a Joystick in qnode.cpp

asked 2013-12-12 23:15:56 -0600

Cookie gravatar image

updated 2014-01-28 17:18:49 -0600

ngrennan gravatar image

Hi there,

i am quite new to ROS and c++, so excuse if if this question is an easy one, plz :)

i created a package with catkin_create_qt_package and now i want to use a JoyListener.

The problem is, that i really don't know how to integrate the code? I found some examples for using the joy.h node, but nothing for using it in the catkin created qt package :( Do i have to add the code in qnode.cpp ?

Sorry for my english XD i don't know how to explain my problem :3

[Edit] Sorry, i don't get it :( I used this code for subscribing the joy-node:

ros::Subscriber sub = n.subscribe<sensor_msgs::Joy>("joy", 10, &QNode::joyCallback);

And this is my prototype of the joyCallback-function:

void QNode::joyCallback(const sensor_msgs::Joy::ConstPtr& joy_msg)
 ros::Publisher chatter_publisher.publish(joy_msg); 

but i get this strange error and don't know what it means...

/usr/include/boost/function/function_template.hpp:225: error: no match for call to ‘(boost::_mfi::mf1<void, test_joy::QNode, const boost::shared_ptr<const sensor_msgs::Joy_<std::allocator<void> > >&>) (const boost::shared_ptr<const sensor_msgs::Joy_<std::allocator<void> > >&)’

do you have any idea of what i'm doing wrong?

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Do you want to receive joystick messages? In that case check out the standard subscriber tutorial.

dornhege gravatar image dornhege  ( 2013-12-13 00:03:29 -0600 )edit

i want to use the joystick for controlling an AR Drone. I thought it would be fine to display the pressed buttons in an QT gui, but i dont know how to check, which button is pressed from the gui package :/

Cookie gravatar image Cookie  ( 2013-12-13 04:54:22 -0600 )edit

If you want to know which buttons are pressed on a running joystick node then subscribe to a sensor_msgs/Joy message. It's usually on the /joy topic.

dornhege gravatar image dornhege  ( 2013-12-13 05:05:33 -0600 )edit

Ok thanks, i'll try it out :)

Cookie gravatar image Cookie  ( 2013-12-13 05:39:06 -0600 )edit

I don't get it >___< i updated the question to what i have done to subscribe the joy-messages.. help plz :(

Cookie gravatar image Cookie  ( 2013-12-13 07:46:53 -0600 )edit

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answered 2013-12-13 10:11:46 -0600

joq gravatar image

The compiler is complaining because the pointer to a JoyStick message passed to your callback is not a valid parameter to the chatter_publisher.publish() method.

What in the world was that statement supposed to do?

ros::Publisher chatter_publisher.publish(joy_msg);

This is not a forum for basic C++ language questions.

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sorry to ask stupid questions, i am new to c++... but i found out that this is not the real problem at all... i deletet this line and replaced it...but it seems as if my subscriber is not even entering my joyCallback(...)... whatever.... :(

Cookie gravatar image Cookie  ( 2013-12-14 01:26:51 -0600 )edit

Aaargh ok i found the mistake, it was the joystick itself..... thanks for helping me! :D

Cookie gravatar image Cookie  ( 2013-12-14 01:33:06 -0600 )edit

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Asked: 2013-12-12 23:15:56 -0600

Seen: 567 times

Last updated: Dec 13 '13