目录

前言

一、创建节点

二、发布话题

三、订阅话题

四、键盘控制

五、运行终端命令

六、案例源码

前言

本案例包括

• 在Qt中创建节点
• 发布话题控制海龟移动
• 订阅话题实时显示海龟位置。
• 键盘控制实现
• qt中运行终端命令

本案例是在ros中创建的qt功能包的基础进行的，在ros中创建qt功能包可以参考下文

ROS下基于Qt的人机交互开发（一）开发环境搭建https://blog.csdn.net/m0_56451176/article/details/126122360?spm=1001.2014.3001.5502

一、创建节点

bool QNode::init() 
{//初始化ROS节点“ros_qt_demo”ros::init(init_argc,init_argv,"ros_qt_demo");//检测ROS节点是否打开if ( ! ros::master::check() ) {return false;}//启动ros::start(); //创建句柄ros::NodeHandle n;//创建发布者chatter_publisher = n.advertise("chatter", 1000);//调用run（）start();return true;
}

注：这个qt功能包自带的init有两种形式，两种init函数中内容相似 

二、发布话题

命令行发布话题请参考：

ROS学习（四）--1.发布者与订阅者案例https://blog.csdn.net/m0_56451176/article/details/126222244?spm=1001.2014.3001.5502

1.在头文件中创建发布者对象turtle_vel_pub;

ros::Publisher turtle_vel_pub;

2.在源文件中定义发布者（init（）中定义，即上文发布者所在函数中）

turtle_vel_pub = n.advertise("/turtle1/cmd_vel", 10);

3.在run（）函数中发布消息

void QNode::run() {ros::Rate loop_rate(1);int count = 0;while ( ros::ok() ){geometry_msgs::Twist vel_msg;vel_msg.linear.x = linevelocity*0.01;vel_msg.angular.z = angular*0.01;// 发布消息turtle_vel_pub.publish(vel_msg);ros::spinOnce();loop_rate.sleep();++count;}std::cout << "Ros shutdown, proceeding to close the gui." << std::endl;Q_EMIT rosShutdown(); // used to signal the gui for a shutdown (useful to roslaunch)
}

在while ( ros::ok() )循环中添加要发布的信息

geometry_msgs::Twist vel_msg;
vel_msg.linear.x = linevelocity*0.01;
vel_msg.angular.z = angular*0.01;

本案例定义了要发布的信息为：海龟x方向线速度和z方向角速度

发布话题：

 turtle_vel_pub.publish(vel_msg);

总结：

1. 创建发布者
2. 定义消息类型和内容
3. 发布消息

三、订阅话题

 命令行订阅话题请参考：

ROS学习（四）--1.发布者与订阅者案例https://blog.csdn.net/m0_56451176/article/details/126222244?spm=1001.2014.3001.5502

1.在头文件中创建发布者对象pose_sub;

ros::Subscriber pose_sub;

2.在源文件中定义发布者（init（）中定义，即上文发布者所在函数中）

pose_sub = n.subscribe("/turtle1/pose", 10, &QNode::poseCallback,this);

注：此处与命令行方式的定义有所不同，

1. 回调函数前要加上“&”和“类名”
2. 回调函数后面再加上“this”

3.创建回调函数

void QNode::poseCallback(const turtlesim::Pose::ConstPtr& msg)
{// 将接收到的消息打印出来std::stringstream ss;ss<<"x:"<x<<"  y:"<y;log(Info,"Turtle pose:"+ss.str());
}

回调函数中对话题进行处理，通过自带的log函数输出

总结：

1. 创建订阅者
2. 定义回调函数

四、键盘控制

void ros_qt_demo::MainWindow::on_pushButton_W_pressed()
{int x=ui.label_6->text().toInt();if(x==0) x=20;ui.horizontalSlider->setValue(x);
}void ros_qt_demo::MainWindow::on_pushButton_W_released()
{ui.horizontalSlider->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_S_pressed()
{int x=ui.label_6->text().toInt();x=0-x;if(x==0) x=-50;ui.horizontalSlider->setValue(x);   
}void ros_qt_demo::MainWindow::on_pushButton_S_released()
{   ui.horizontalSlider->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_A_pressed()
{int x=ui.label_7->text().toInt();if(x==0) x=50;ui.horizontalSlider_2->setValue(x);
}void ros_qt_demo::MainWindow::on_pushButton_A_released()
{ui.horizontalSlider_2->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_D_pressed()
{int x=ui.label_7->text().toInt();x=0-x;if(x==0) x=-50;ui.horizontalSlider_2->setValue(x);
}void ros_qt_demo::MainWindow::on_pushButton_D_released()
{ui.horizontalSlider_2->setValue(0);
}

由于发布话题和ui分别写在两个不同的类中，需要通过信号与槽机制建立连接。

1.main_window.hpp

signals:void getlinevelocity(int velocity);void getlangular(int velocity);

2.qnode.hpp

  public slots:void on_getlinevelocity(int velocity);void on_getlangular(int velocity);

3.连接

connect(this,SIGNAL(getlinevelocity(int)),&qnode,SLOT(on_getlinevelocity(int)));
connect(this,SIGNAL(getlangular(int)),&qnode,SLOT(on_getlangular(int)));

五、运行终端命令

void ros_qt_demo::MainWindow::on_pushButton_3_clicked()
{QProcess *process=new QProcess;//打开终端process->start("bash");//写入命令process->write(ui.textEdit->toPlainText().toLocal8Bit()+'\n');ui.textBrowser->append(process->readAll().data());
}

 注：process->write(ui.textEdit->toPlainText().toLocal8Bit()+'\n');中‘\n’不可省略

六、案例源码

1.main_window.hpp

/*** @file /include/ros_qt_demo/main_window.hpp** @brief Qt based gui for ros_qt_demo.** @date November 2010**/
#ifndef ros_qt_demo_MAIN_WINDOW_H
#define ros_qt_demo_MAIN_WINDOW_H/*****************************************************************************
** Includes
*****************************************************************************/#include 
#include "ui_main_window.h"
#include "qnode.hpp"/*****************************************************************************
** Namespace
*****************************************************************************/namespace ros_qt_demo {/*****************************************************************************
** Interface [MainWindow]
*****************************************************************************/
/*** @brief Qt central, all operations relating to the view part here.*/
class MainWindow : public QMainWindow {
Q_OBJECTsignals:void getlinevelocity(int velocity);void getlangular(int velocity);public:MainWindow(int argc, char** argv, QWidget *parent = 0);~MainWindow();void ReadSettings(); // Load up qt program settings at startupvoid WriteSettings(); // Save qt program settings when closingvoid closeEvent(QCloseEvent *event); // Overloaded functionvoid showNoMasterMessage();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 automaticallyprivate slots:void on_horizontalSlider_valueChanged(int value);void on_horizontalSlider_2_valueChanged(int value);void on_pushButton_clicked();void on_pushButton_2_clicked();void on_pushButton_W_pressed();void on_pushButton_W_released();void on_pushButton_S_pressed();void on_pushButton_S_released();void on_pushButton_A_pressed();void on_pushButton_A_released();void on_pushButton_D_pressed();void on_pushButton_D_released();void on_pushButton_3_clicked();private:Ui::MainWindowDesign ui;QNode qnode;
};}  // namespace ros_qt_demo#endif // ros_qt_demo_MAIN_WINDOW_H

2.main_window.cpp

/*** @file /src/main_window.cpp** @brief Implementation for the qt gui.** @date February 2011**/
/*****************************************************************************
** Includes
*****************************************************************************/#include 
#include 
#include 
#include "../include/ros_qt_demo/main_window.hpp"
#include/*****************************************************************************
** Namespaces
*****************************************************************************/namespace ros_qt_demo {using namespace Qt;/*****************************************************************************
** Implementation [MainWindow]
*****************************************************************************/MainWindow::MainWindow(int argc, char** argv, QWidget *parent): QMainWindow(parent), qnode(argc,argv)
{ui.setupUi(this); // Calling this incidentally connects all ui's triggers to on_...() callbacks in this class.QObject::connect(ui.actionAbout_Qt, SIGNAL(triggered(bool)), qApp, SLOT(aboutQt())); // qApp is a global variable for the applicationReadSettings();setWindowIcon(QIcon(":/images/icon.png"));ui.tab_manager->setCurrentIndex(0); // ensure the first tab is showing - qt-designer should have this already hardwired, but often loses it (settings?).QObject::connect(&qnode, SIGNAL(rosShutdown()), this, SLOT(close()));/*********************** Logging**********************/ui.view_logging->setModel(qnode.loggingModel());QObject::connect(&qnode, SIGNAL(loggingUpdated()), this, SLOT(updateLoggingView()));/*********************** Auto Start**********************/if ( ui.checkbox_remember_settings->isChecked() ) {on_button_connect_clicked(true);}connect(this,SIGNAL(getlinevelocity(int)),&qnode,SLOT(on_getlinevelocity(int)));connect(this,SIGNAL(getlangular(int)),&qnode,SLOT(on_getlangular(int)));
}MainWindow::~MainWindow() {}/*****************************************************************************
** Implementation [Slots]
*****************************************************************************/void MainWindow::showNoMasterMessage() {QMessageBox msgBox;msgBox.setText("Couldn't find the ros master.");msgBox.exec();close();
}/** These triggers whenever the button is clicked, regardless of whether it* is already checked or not.*/void MainWindow::on_button_connect_clicked(bool check ) {if ( ui.checkbox_use_environment->isChecked() ) {if ( !qnode.init() ) {showNoMasterMessage();} else {ui.button_connect->setEnabled(false);}} else {if ( ! qnode.init(ui.line_edit_master->text().toStdString(),ui.line_edit_host->text().toStdString()) ) {showNoMasterMessage();} else {ui.button_connect->setEnabled(false);ui.line_edit_master->setReadOnly(true);ui.line_edit_host->setReadOnly(true);ui.line_edit_topic->setReadOnly(true);}}
}void MainWindow::on_checkbox_use_environment_stateChanged(int state) {bool enabled;if ( state == 0 ) {enabled = true;} else {enabled = false;}ui.line_edit_master->setEnabled(enabled);ui.line_edit_host->setEnabled(enabled);//ui.line_edit_topic->setEnabled(enabled);
}/*****************************************************************************
** Implemenation [Slots][manually connected]
*****************************************************************************//*** This function is signalled by the underlying model. When the model changes,* this will drop the cursor down to the last line in the QListview to ensure* the user can always see the latest log message.*/
void MainWindow::updateLoggingView() {ui.view_logging->scrollToBottom();
}/*****************************************************************************
** Implementation [Menu]
*****************************************************************************/void MainWindow::on_actionAbout_triggered() {QMessageBox::about(this, tr("About ..."),tr("
PACKAGE_NAME Test Program 0.10
Copyright Yujin Robot
This package needs an about description.
"));
}/*****************************************************************************
** Implementation [Configuration]
*****************************************************************************/void MainWindow::ReadSettings() {QSettings settings("Qt-Ros Package", "ros_qt_demo");restoreGeometry(settings.value("geometry").toByteArray());restoreState(settings.value("windowState").toByteArray());QString master_url = settings.value("master_url",QString("http://192.168.1.2:11311/")).toString();QString host_url = settings.value("host_url", QString("192.168.1.3")).toString();//QString topic_name = settings.value("topic_name", QString("/chatter")).toString();ui.line_edit_master->setText(master_url);ui.line_edit_host->setText(host_url);//ui.line_edit_topic->setText(topic_name);bool remember = settings.value("remember_settings", false).toBool();ui.checkbox_remember_settings->setChecked(remember);bool checked = settings.value("use_environment_variables", false).toBool();ui.checkbox_use_environment->setChecked(checked);if ( checked ) {ui.line_edit_master->setEnabled(false);ui.line_edit_host->setEnabled(false);//ui.line_edit_topic->setEnabled(false);}
}void MainWindow::WriteSettings() {QSettings settings("Qt-Ros Package", "ros_qt_demo");settings.setValue("master_url",ui.line_edit_master->text());settings.setValue("host_url",ui.line_edit_host->text());//settings.setValue("topic_name",ui.line_edit_topic->text());settings.setValue("use_environment_variables",QVariant(ui.checkbox_use_environment->isChecked()));settings.setValue("geometry", saveGeometry());settings.setValue("windowState", saveState());settings.setValue("remember_settings",QVariant(ui.checkbox_remember_settings->isChecked()));}void MainWindow::closeEvent(QCloseEvent *event)
{WriteSettings();QMainWindow::closeEvent(event);
}}  // namespace ros_qt_demovoid ros_qt_demo::MainWindow::on_horizontalSlider_valueChanged(int value)
{ui.label_6->setText(QString::number(value));emit getlinevelocity(value);
}void ros_qt_demo::MainWindow::on_horizontalSlider_2_valueChanged(int value)
{ui.label_7->setText(QString::number(value));emit getlangular(value);}void ros_qt_demo::MainWindow::on_pushButton_clicked()
{ui.horizontalSlider->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_2_clicked()
{ui.horizontalSlider_2->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_W_pressed()
{int x=ui.label_6->text().toInt();if(x==0) x=20;ui.horizontalSlider->setValue(x);}void ros_qt_demo::MainWindow::on_pushButton_W_released()
{ui.horizontalSlider->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_S_pressed()
{int x=ui.label_6->text().toInt();x=0-x;if(x==0) x=-50;ui.horizontalSlider->setValue(x);   
}void ros_qt_demo::MainWindow::on_pushButton_S_released()
{   ui.horizontalSlider->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_A_pressed()
{int x=ui.label_7->text().toInt();if(x==0) x=50;ui.horizontalSlider_2->setValue(x);}void ros_qt_demo::MainWindow::on_pushButton_A_released()
{ui.horizontalSlider_2->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_D_pressed()
{int x=ui.label_7->text().toInt();x=0-x;if(x==0) x=-50;ui.horizontalSlider_2->setValue(x);}void ros_qt_demo::MainWindow::on_pushButton_D_released()
{ui.horizontalSlider_2->setValue(0);
}void ros_qt_demo::MainWindow::on_pushButton_3_clicked()
{QProcess *process=new QProcess;//打开终端process->start("bash");//写入命令process->write(ui.textEdit->toPlainText().toLocal8Bit()+'\n');ui.textBrowser->append(process->readAll().data());
}

3.qnode.hpp

/*** @file /include/ros_qt_demo/qnode.hpp** @brief Communications central!** @date February 2011**/
/*****************************************************************************
** Ifdefs
*****************************************************************************/#ifndef ros_qt_demo_QNODE_HPP_
#define ros_qt_demo_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 
#endif
#include 
#include 
#include #include 
#include "turtlesim/Pose.h"/*****************************************************************************
** Namespaces
*****************************************************************************/namespace ros_qt_demo {/*****************************************************************************
** Class
*****************************************************************************/class QNode : public QThread {Q_OBJECT
public:QNode(int argc, char** argv );virtual ~QNode();bool init();bool init(const std::string &master_url, const std::string &host_url);void run();/*********************** Logging**********************/enum LogLevel {Debug,Info,Warn,Error,Fatal};QStringListModel* loggingModel() { return &logging_model; }void log( const LogLevel &level, const std::string &msg);int linevelocity=0;int angular=0;Q_SIGNALS:void loggingUpdated();void rosShutdown();private:int init_argc;char** init_argv;//ros::Publisher chatter_publisher;ros::Publisher turtle_vel_pub;ros::Subscriber pose_sub;void poseCallback(const turtlesim::Pose::ConstPtr& msg);QStringListModel logging_model;public slots:void on_getlinevelocity(int velocity);void on_getlangular(int velocity);};}  // namespace ros_qt_demo#endif /* ros_qt_demo_QNODE_HPP_ */

4.qnode.cpp

/*** @file /src/qnode.cpp** @brief Ros communication central!** @date February 2011**//*****************************************************************************
** Includes
*****************************************************************************/#include 
#include 
#include 
#include 
#include 
#include "../include/ros_qt_demo/qnode.hpp"
#include/*****************************************************************************
** Namespaces
*****************************************************************************/namespace ros_qt_demo {/*****************************************************************************
** Implementation
*****************************************************************************/QNode::QNode(int argc, char** argv ) :init_argc(argc),init_argv(argv){}QNode::~QNode() {if(ros::isStarted()) {ros::shutdown(); // explicitly needed since we use ros::start();ros::waitForShutdown();}wait();
}bool QNode::init() 
{//初始化ROS节点“ros_qt_demo”ros::init(init_argc,init_argv,"ros_qt_demo");//检测ROS节点是否打开if ( ! ros::master::check() ) {return false;}ros::start(); // explicitly needed since our nodehandle is going out of scope.//创建句柄ros::NodeHandle n;// Add your ros communications here.
//	chatter_publisher = n.advertise("chatter", 1000);turtle_vel_pub = n.advertise("/turtle1/cmd_vel", 10);pose_sub = n.subscribe("/turtle1/pose", 10, &QNode::poseCallback,this);//调用run（）start();return true;
}bool QNode::init(const std::string &master_url, const std::string &host_url) {std::map remappings;remappings["__master"] = master_url;remappings["__hostname"] = host_url;ros::init(remappings,"ros_qt_demo");if ( ! ros::master::check() ) {return false;}ros::start(); // explicitly needed since our nodehandle is going out of scope.ros::NodeHandle n;// Add your ros communications here.
//	chatter_publisher = n.advertise("chatter", 1000);turtle_vel_pub = n.advertise("/turtle1/cmd_vel", 10);pose_sub = n.subscribe("/turtle1/pose", 10, &QNode::poseCallback,this);start();return true;
}void QNode::poseCallback(const turtlesim::Pose::ConstPtr& msg)
{// 将接收到的消息打印出来std::stringstream ss;ss<<"x:"<x<<"  y:"<y;log(Info,"Turtle pose:"+ss.str());}void QNode::run() {ros::Rate loop_rate(1);int count = 0;while ( ros::ok() ) {geometry_msgs::Twist vel_msg;vel_msg.linear.x = linevelocity*0.01;vel_msg.angular.z = angular*0.01;// 发布消息turtle_vel_pub.publish(vel_msg);//		std_msgs::String msg;
//		std::stringstream ss;
//		ss << "hello world " << count;
//		msg.data = ss.str();
//		chatter_publisher.publish(msg);
//		log(Info,std::string("I sent: ")+msg.data);ros::spinOnce();loop_rate.sleep();++count;}std::cout << "Ros shutdown, proceeding to close the gui." << std::endl;Q_EMIT rosShutdown(); // used to signal the gui for a shutdown (useful to roslaunch)
}void QNode::on_getlinevelocity(int velocity)
{linevelocity=velocity;
}void QNode::on_getlangular(int velocity){angular=velocity;}void QNode::log( const LogLevel &level, const std::string &msg) {logging_model.insertRows(logging_model.rowCount(),1);std::stringstream logging_model_msg;switch ( level ) {case(Debug) : {ROS_DEBUG_STREAM(msg);logging_model_msg << "[DEBUG] [" << ros::Time::now() << "]: " << msg;break;}case(Info) : {ROS_INFO_STREAM(msg);logging_model_msg << "[INFO] [" << ros::Time::now() << "]: " << msg;break;}case(Warn) : {ROS_WARN_STREAM(msg);logging_model_msg << "[INFO] [" << ros::Time::now() << "]: " << msg;break;}case(Error) : {ROS_ERROR_STREAM(msg);logging_model_msg << "[ERROR] [" << ros::Time::now() << "]: " << msg;break;}case(Fatal) : {ROS_FATAL_STREAM(msg);logging_model_msg << "[FATAL] [" << ros::Time::now() << "]: " << msg;break;}}QVariant new_row(QString(logging_model_msg.str().c_str()));logging_model.setData(logging_model.index(logging_model.rowCount()-1),new_row);Q_EMIT loggingUpdated(); // used to readjust the scrollbar
}}  // namespace ros_qt_demo

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