qt学习之利用滑动条控制小乌龟速度（三）

程序：main_window.hpp:

/**
 * @file /include/gui/main_window.hpp
 *
 * @brief Qt based gui for gui.
 *
 * @date November 2010
 **/
#ifndef gui_MAIN_WINDOW_H
#define gui_MAIN_WINDOW_H

/*****************************************************************************
** Includes
*****************************************************************************/

#include <QtGui/QMainWindow>
#include "ui_main_window.h"
#include "qnode.hpp"

/*****************************************************************************
** Namespace
*****************************************************************************/

namespace gui {

//float angular_value = 0.0 ;
//float turtle_angular = 0.0;
/*****************************************************************************
** Interface [MainWindow]
*****************************************************************************/
/**
 * @brief Qt central, all operations relating to the view part here.
 */
class MainWindow : public QMainWindow {
Q_OBJECT

public:
	MainWindow(int argc, char** argv, QWidget *parent = 0);
	~MainWindow();

	void ReadSettings(); // Load up qt program settings at startup
	void WriteSettings(); // Save qt program settings when closing

	void closeEvent(QCloseEvent *event); // Overloaded function
	void showNoMasterMessage();
  float right_angular_value = 0 ;
  float right_linear_value = 0 ;
  float left_angular_value = 0 ;
  float left_linear_value = 0 ;
  float backward_angular_value = 0 ;
  float backward_linear_value = 0 ;
  float forward_angular_value = 0 ;
  float forward_linear_value = 0 ;
public Q_SLOTS:
	/******************************************
	** Auto-connections (connectSlotsByName())
	*******************************************/
	void on_actionAbout_triggered();
	void on_button_connect_clicked(bool check );
	void on_checkbox_use_environment_stateChanged(int state);

    /******************************************
    ** Manual connections
    *******************************************/
   void updateLoggingView(); // no idea why this can't connect automatically

private Q_SLOTS:
    void on_forward_clicked();

    void on_backward_clicked();

    void on_right_clicked();

    void on_left_clicked();

    void on_AngularSlider_valueChanged(int value);
    void on_AngularSlider_left_valueChanged(int value);

    void on_LinearSlider_backward_valueChanged(int value);

    void on_LinearSlider_forward_valueChanged(int value);

private:
	Ui::MainWindowDesign ui;
	QNode qnode;

};

}  // namespace gui

#endif // gui_MAIN_WINDOW_H

qnode.hpp:

/**
 * @file /include/gui/qnode.hpp
 *
 * @brief Communications central!
 *
 * @date February 2011
 **/
/*****************************************************************************
** Ifdefs
*****************************************************************************/

#ifndef gui_QNODE_HPP_
#define gui_QNODE_HPP_

/*****************************************************************************
** Includes
*****************************************************************************/

// To workaround boost/qt4 problems that won't be bugfixed. Refer to
//    https://bugreports.qt.io/browse/QTBUG-22829
#ifndef Q_MOC_RUN
#include <ros/ros.h>
#endif
#include <string>
#include <QThread>
#include <QStringListModel>


/*****************************************************************************
** Namespaces
*****************************************************************************/

namespace gui {
//float angular_value = 0 ;
//float turtle_angular = 0;

/*****************************************************************************
** Class
*****************************************************************************/
//float turtle_linear = 0.0;
class QNode : public QThread {
    Q_OBJECT

public:
	QNode(int argc, char** argv );
	virtual ~QNode();
  bool init();
  bool init(const std::string