关于QUdpSocket和Qwt动态曲线的小例子

        最近项目中遇到的一个需求是关于用udp接收数据来显示一个动态曲线，觉得以后可能还会遇到于是写一个小例子记录一下。废话不多说直接贴代码。

        首先是数据发送端：

新建一个Qt Widgets Application，选择Qwidget，其中工程文件如下：

其中主要是QudpSocket的使用其他没什么可说的。

#-------------------------------------------------

#

# Project created by QtCreator 2018-06-07T19:21:13

#

#-------------------------------------------------

QT       += core gui network

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = QUdpServer

TEMPLATE = app

SOURCES += main.cpp\

        widgetserver.cpp

HEADERS  += widgetserver.h \

#    thetestdata.h

FORMS    += widgetserver.ui

头文件如下：

#ifndef WIDGETSERVER_H

#define WIDGETSERVER_H

#include <QWidget>

#include <QUdpSocket>

#include <QDebug>

namespace Ui {

class WidgetServer;

}

class WidgetServer : public QWidget

{

    Q_OBJECT

public:

    explicit WidgetServer(QWidget *parent = 0);

    ~WidgetServer();

private slots:

    void on_pushButton_send_clicked();

    void time_out_Slot();

private:

    void initSorket();

private:

    Ui::WidgetServer *ui;

    QUdpSocket* sender;

    QTimer*     timer;

};

#endif // WIDGETSERVER_H

源文件：

#include "widgetserver.h"

#include "ui_widgetserver.h"

#include "thetestdata.h"

#include <QDebug>

#include <QTime>

#include <QTimer>

WidgetServer::WidgetServer(QWidget *parent) :

    QWidget(parent),

    ui(new Ui::WidgetServer)

{

    ui->setupUi(this);

    timer = new QTimer(this);

    timer->start(1000);

    initSorket();

    connect(timer, SIGNAL(timeout()), this, SLOT(time_out_Slot()));

}

WidgetServer::~WidgetServer()

{

    delete ui;

}

//初始化QUdpSocket

void WidgetServer::initSorket()

{

    sender = new QUdpSocket(this);

    sender->bind(QHostAddress::Broadcast, 7755);

}

void WidgetServer::on_pushButton_send_clicked()

{

}

//时间槽函数 并对数据进行赋值发送

void WidgetServer::time_out_Slot()

{

    Massege_Data msg;

    int msg_length = sizeof(Massege_Data);

    qDebug()<<msg_length;

    memset(&msg,0,sizeof(Massege_Data));

    msg.massege_header.massege_header = 1001;

    msg.massege_header.msg_num = 1;

    msg.test_data1 = 1;

    msg.test_data2 = 2;

    msg.massege_header.massege_length_uh = sizeof(Massege_Data);

    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));

    for(int i=0 ; i< 100;++i)

    {

        msg.the_y[i]= qrand()%90;

    }

    sender->writeDatagram((char*)&msg,sizeof(Massege_Data),QHostAddress::LocalHost,7755);

    //    qreal xy = sender->write((char*)&msg,sizeof(Massege_Data));

    //    if(xy==-1)

    //    {

    //        qDebug()<<sender->errorString();

    //    }

}

其中的结构体是单独的一个文件thetestdata.h放在和发送端的头文件和源文件相同的目录中：

#ifndef THETESTDATA_H

#define THETESTDATA_H

#pragma pack(1)

#ifndef _MASSEGE_HEADER

#define _MASSEGE_HEADER

typedef struct MassegeHeader{

    unsigned short int massege_header;//消息头

    unsigned short int massege_length_uh;//消息长度

    unsigned short int msg_num;//包数号

    unsigned short int msg_num_all;//总包数

    unsigned int       time_e;//时间戳

    unsigned char      spare_uc[9];//消息源

    unsigned char      bak[3];

}MassegeHeader;

#endif

#ifndef _MAGGEGE_DATA

#define _MAGGEGE_DATA

typedef struct Massege_Data{

    MassegeHeader         massege_header;

    unsigned short int    test_data1;

    unsigned short int    test_data2;

    unsigned short int    the_y[100];

}Massege_Data;

#endif

#pragma pack()

#endif // THETESTDATA_H

接下来是接收端也是新建Qt Widgets Application，选择Qwidget，要稍微复杂一点的就是重写了Qwt：

其界面如图：

其工程文件如下：

#-------------------------------------------------

#

# Project created by QtCreator 2018-06-09T20:57:32

#

#-------------------------------------------------

QT       += core gui network

CONFIG += qwt

DEFINES += QT_DLL QWT_DLL

LIBS += -L"D:\build-qwt-Desktop_Qt_5_6_3_MSVC2013_64bit-Debug\lib" -lqwtd

LIBS += -L"D:\build-qwt-Desktop_Qt_5_6_3_MSVC2013_64bit-Debug\lib" -lqwt

INCLUDEPATH += F:\Qt\Qt5.6.3\5.6.3\msvc2013_64\include\QWT

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = UdpClient

TEMPLATE = app

SOURCES += main.cpp\

        clientwidget.cpp

HEADERS  += clientwidget.h

FORMS    += clientwidget.ui

头文件如下：

#ifndef CLIENTWIDGET_H

#define CLIENTWIDGET_H

#include <QWidget>

#include <qmath.h>

#include <QVector>

#include <qwt_plot.h>

#include <qwt_plot_curve.h>

#include <qwt_plot_magnifier.h>

#include <qwt_plot_panner.h>

#include <qwt_legend.h>

#include <qwt_point_data.h>

#include <qwt_plot_grid.h>

#include <qwt_plot_picker.h>

#include <qwt_picker.h>

#include <QColor>

#include <QDebug>

#include <QUdpSocket>

#include <QPen>

#include <QTimer>

namespace Ui {

class ClientWidget;

}

class ClientWidget : public QWidget

{

    Q_OBJECT

public:

    explicit ClientWidget(QWidget *parent = 0);

    ~ClientWidget();

    //设置画布标题

    void setPlotTitle(const QString &strTitle);

    //重绘

    void reDraw();

    //设置x轴，y轴信息

    void setAxisTitles(QwtPlot::Axis asixId,const QString &strText);

    //设置x，y的值

    void setAxisRange(QwtPlot::Axis asixId,const double dStart,const double dEnd,const double dIndex=0.0);

    //创建网格

    QwtPlotGrid* createGrid();

    //获取网格

    QwtPlotGrid* getGrid();

    //设置是否显示

    void setGridIsShow(QwtPlot::Axis asixId,bool show);

    //设置网格类型和颜色

    void setGridColor(QColor color,qreal qrlinewidth,Qt::PenStyle ePenStyle);

    //创建曲线

    QwtPlotCurve* createCurve();

    //设置曲线是否显示

    void setCurveIsShow(QwtPlotCurve* pCurve,bool show);

    //删除曲线

    void delCurve(QwtPlotCurve* pCurve);

    //设置曲线数据和颜色

    void setCurveData(QwtPlotCurve* pCurve, QwtPointArrayData * const data,QPen pen);

    void addItem(int ixPos,int iYPos,const QwtText &qwtText);

    void delItem(QwtPlotItem *plotItem);

    void setItemPos(QwtPlotItem *plotItem,int ixPos,int iyPos);

    void setItemIsShow(QwtPlotItem *plotItem,bool show);

    void setTipMsg(QPoint pos,QString strText);

protected:

    void resizeEvent(QResizeEvent* re);

private slots:

    void on_pushButton_clicked();

    void readPendingDatagrams();

    void time_out_Slot();

private:

    Ui::ClientWidget *ui;

    QList<QwtPlotCurve*> m_listCurve;

    QList<QwtPlotItem*>  m_listItem;

    QwtPlotGrid *m_plotGrid;

    QwtPlot*     m_plot;

    QwtPlotPicker * m_picker;

    double  m_dXStart,m_dYStart,m_dXEnd,m_dYEnd;

    QUdpSocket* recvUdpSocket;

    QwtPlotCurve* testCurve;

    QwtPlotCurve* Msg_Udp_Curve;

    QTimer *timer;

};

#endif // CLIENTWIDGET_H

源文件如下：

#include "clientwidget.h"

#include "ui_clientwidget.h"

#include <QFont>

#include <QPolygonF>

#include <QResizeEvent>

#include "thetestdata.h"

#include <QTime>

ClientWidget::ClientWidget(QWidget *parent) :

    QWidget(parent),

    ui(new Ui::ClientWidget)

{

    ui->setupUi(this);

    m_plot = NULL;

    m_plot = ui->plot;

    m_plotGrid = NULL;

    createGrid();

    m_listCurve.clear();

    m_listItem.clear();

    m_picker = new QwtPlotPicker(QwtPlot::xBottom,QwtPlot::yLeft,

                                  QwtPicker::PolygonRubberBand,

                                  QwtPicker::AlwaysOn,m_plot->canvas());

    m_picker->setRubberBandPen(QColor(Qt::green));

    m_picker->setRubberBand(QwtPicker::CrossRubberBand);

    m_picker->setTrackerPen(QColor(Qt::black));

    (void) new QwtPlotMagnifier(m_plot->canvas());

     (void) new QwtPlotPanner( m_plot->canvas() );

    recvUdpSocket = new QUdpSocket(this);

    recvUdpSocket->bind(QHostAddress::LocalHost, 7755);

    connect(recvUdpSocket, SIGNAL(readyRead()),

                  this, SLOT(readPendingDatagrams()));

    timer = new QTimer(this);

    timer->start(1000);

    //connect(timer, SIGNAL(timeout()), this, SLOT(time_out_Slot()));

    testCurve = NULL;

    testCurve = createCurve();

    Msg_Udp_Curve = NULL;

    Msg_Udp_Curve = createCurve();

}

ClientWidget::~ClientWidget()

{

    delete ui;

}

void ClientWidget::setPlotTitle(const QString &strTitle)

{

    QwtText qwtText = QwtText(strTitle);

    qwtText.setFont(QFont("Bitstream Charter",12,50,false));

    m_plot->setTitle(qwtText);

}

void ClientWidget::reDraw()

{

    m_plot->replot();

//    m_plot->detachItems();

}

void ClientWidget::setAxisTitles(QwtPlot::Axis asixId, const QString &strText)

{

    QwtText qwtText = QwtText(strText);

    qwtText.setFont(QFont("Bitstream Charter",9,50,false));

    m_plot->setAxisTitle(asixId,qwtText);

}

void ClientWidget::setAxisRange(QwtPlot::Axis asixId, const double dStart, const double dEnd, const double dIndex)

{

    m_plot->setAxisScale(asixId,dStart,dEnd,dIndex);

    if(asixId==QwtPlot::xBottom)

    {

        m_dXStart = dStart;

        m_dXEnd   = dEnd;

    }

    else if (asixId==QwtPlot::yLeft)

    {

        m_dYStart = dStart;

        m_dYEnd   = dEnd;

    }

}

QwtPlotGrid *ClientWidget::createGrid()

{

    if(m_plotGrid != NULL) return m_plotGrid;

    m_plotGrid = new QwtPlotGrid;

    setGridColor(Qt::gray,0.0,Qt::DotLine);

    m_plotGrid->attach(m_plot);

}

QwtPlotGrid *ClientWidget::getGrid()

{

    return m_plotGrid;

}

void ClientWidget::setGridIsShow(QwtPlot::Axis asixId, bool show)

{

    if(m_plotGrid == NULL) return;

    if(asixId == QwtPlot::xBottom)

        m_plotGrid->enableX(show);

    else if(asixId == QwtPlot::yLeft)

        m_plotGrid->enableY(show);

}

void ClientWidget::setGridColor(QColor color, qreal qrlinewidth, Qt::PenStyle ePenStyle)

{

    if(m_plotGrid == NULL) return;

    m_plotGrid->setPen(QPen(color,qrlinewidth,ePenStyle));

}

QwtPlotCurve *ClientWidget::createCurve()

{

    QwtPlotCurve* pCurve = new QwtPlotCurve();

    pCurve->setRenderHint(QwtPlotItem::RenderAntialiased);

    m_listCurve.append(pCurve);

    pCurve->attach(m_plot);

    return pCurve;

}

void ClientWidget::setCurveIsShow(QwtPlotCurve *pCurve, bool show)

{

    if(show)

    {

        if(!m_listCurve.contains(pCurve))

            m_listCurve.append(pCurve);

        pCurve->attach(m_plot);

    }

    else

    {

        pCurve->detach();

    }

}

void ClientWidget::delCurve(QwtPlotCurve *pCurve)

{

    if(m_listCurve.contains(pCurve)) return;

    m_listCurve.removeOne(pCurve);

    pCurve->detach();

    delete pCurve;

    pCurve = NULL;

}

void ClientWidget::setCurveData(QwtPlotCurve *pCurve,QwtPointArrayData * const data, QPen pen)

{

    if(pCurve != NULL)

        pCurve->setData(data);

    pCurve->setPen(pen);

}

void ClientWidget::addItem(int ixPos, int iYPos, const QwtText &qwtText)

{

}

void ClientWidget::delItem(QwtPlotItem *plotItem)

{

}

void ClientWidget::setItemPos(QwtPlotItem *plotItem, int ixPos, int iyPos)

{

}

void ClientWidget::setItemIsShow(QwtPlotItem *plotItem, bool show)

{

}

void ClientWidget::setTipMsg(QPoint pos, QString strText)

{

}

void ClientWidget::resizeEvent(QResizeEvent *re)

{

    int w = re->size().width();

    QWidget::resizeEvent(re);

}

void ClientWidget::on_pushButton_clicked()

{

    timer->stop();

}

void ClientWidget::readPendingDatagrams()

{

    Massege_Data msg;

    memset(&msg,0,sizeof(Massege_Data));

    while (recvUdpSocket->hasPendingDatagrams()) {

            QByteArray datagram;

            QHostAddress sender = QHostAddress::LocalHost;

            quint16 senderPort = 7755;

            datagram.resize(recvUdpSocket->pendingDatagramSize());

            recvUdpSocket->readDatagram((char*)&msg, sizeof(Massege_Data),

                                    &sender,&senderPort);

        }

        QVector<double> xs;

        QVector<double> ys;

        for (int i=0;i<100;++i)

        {

            ys.append(msg.the_y[i]);

            xs.append(i);

        }

        //构造曲线数据

        QwtPointArrayData * const data = new QwtPointArrayData(xs, ys);

//

        setAxisRange(QwtPlot::xBottom,0,100);

        setAxisRange(QwtPlot::yLeft,0,100);

        setAxisTitles(QwtPlot::xBottom,"x__");

        setAxisTitles(QwtPlot::yLeft,QString("y__"));

        setCurveData(Msg_Udp_Curve,data,QPen(Qt::blue));

        reDraw();

}

void ClientWidget::time_out_Slot()

{

    if(testCurve != NULL)

        delCurve(testCurve);

    Massege_Data msg_test;

    int msg_length = sizeof(Massege_Data);

    qDebug()<<msg_length;

    memset(&msg_test,0,sizeof(Massege_Data));

    msg_test.massege_header.massege_header = 1001;

    msg_test.massege_header.msg_num = 1;

    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));

    for(int i=0 ; i< 100;++i)

    {

           msg_test.the_y[i] = qrand()%90;

    }

    QVector<double> xs;

    QVector<double> ys;

    for (int i=0;i<100;++i)

    {

        ys.append(msg_test.the_y[i]);

        xs.append(i);

    }

    //构造曲线数据

    QwtPointArrayData * const data = new QwtPointArrayData(xs, ys);

    setAxisRange(QwtPlot::xBottom,0,100);

    setAxisRange(QwtPlot::yLeft,0,100);

    setCurveData(testCurve,data,QPen(Qt::red));

    reDraw();

}

其中结构体文件和发送端一样也是放在与接收端的源文件一个目录。

其显示的效果如下: