Is data received from serial port possible to view on two forms?

[JonB]

@Shivam-Sharma
As @J-Hilk has said. And further to that: (unless a Qt expert contradicts me) you should never be including mainwindow.h into anything other than mainwindow.cpp and your main.cpp, not into any other UI stuff you define. Keeps it clean --- they should never need to know about your MainWindow class. This is true all over the place: a widget which accesses/opens a "child" widget should include that child's .h file, but the "child" widgets should never need to know about/include the .h file of other ("parent") widgets where they might be called from. At least usually.

[Shivam Sharma]

This post is deleted!

[Shivam Sharma]

@J-Hilk @JonB

Thank you so much guys. This really helped me. All the solutions that you'll constantly engaged me with really means a lot. Appreciate this.

[SGaist]

Hi,

One small addition, when passing QString around like that (but it is also valid for other classes), it's a good habit to use const references. This allows to avoid creating unneeded copies.

[Shivam Sharma]

@J-Hilk @JonB Hi guys. Need one more help. If i want to add a push button on the Setup form that connects and disconnects the serial data incoming on both the forms how could I do that.

This is the code for the push button, i can do it on the mainwindow form but unable to do it on the Setup form since it is not being able to access *serial.

Code:

void MainWindow::on_start_toggled(bool checked)
{
    ui->start->setText(ui->start->isChecked() ? "Connect" : "Disconnect");
    if (checked)
    {
        serial->close();
        ui->start->setStyleSheet(QString("QPushButton {background-color: rgb(115, 210, 22);}"));
    }
    else
    {
        ui->start->setStyleSheet(QString("QPushButton {background-color: red;}"));


           serial = new QSerialPort(this);
           serial = new QSerialPort(this);
           serial->setPortName("ttyUSB0");
           serial->setBaudRate(QSerialPort::Baud9600);
           serial->setDataBits(QSerialPort::Data8);
           serial->setParity(QSerialPort::NoParity);
           serial->setStopBits(QSerialPort::OneStop);
           serial->setFlowControl(QSerialPort::NoFlowControl);

           if( serial->open(QIODevice::ReadWrite))
            {
                qDebug()<<"Port Open OK";
                connect(serial, &QSerialPort::readyRead, this, &MainWindow::serialReceived);
            }
          else
            {
                qDebug()<<"Can't Open Port : " << serial->error();
            }
           serialReceived();
    }
}

[jsulm]

@Shivam-Sharma Create a signal in Setup, connect that signal to clicked() signal of the button in Setup and then connect the signal you created in Setup (the first one I mentioned) to a slot in MainWindow where you can enable/disable the serial port.

[Shivam Sharma]

I am sorry, but unable to understand. How do i connect the pushbutton to mainwindow from Setup form, since i cannot inherit the parent class, neither can i create an instance of it. Could you give a demo?

[jsulm]

@Shivam-Sharma said in Is data received from serial port possible to view on two forms?:

How do i connect the pushbutton to mainwindow from Setup form

You don't, please read more carefully.

class Setup
{
signals:
    void onOffSerialPort();
};

void Setup::Setup()
{
    connect(ui->button, &QPushButton::clicked, this, &Setup::onOffSerialButton);
}

// MainWindow
connect(setup, &Setup::onOffSerialButton, this, &MainWindow::onOffSerialButton);

As you can see Setup does not know anything about MainWindow.

[Shivam Sharma]

// MainWindow
connect(setup, &Setup::onOffSerialButton, this, &MainWindow::onOffSerialButton);

shouldn't all of this be

onOffSerialPort

and the last part be :

&MainWindow::close);

void Mainwindow::close()
{
serial->close();
}

[jsulm]

@Shivam-Sharma Sorry, I don't understand what you mean. The code I provided is just to show the idea, you need to adapt it to your needs.

[J.Hilk]

let me expand on @jsulm example

first of in your mainwindow, create a new function, defined as a slot

and copy the content of your on button clicked in there

public slots:
     void toggleSerial(bool checked);

//mainwindow.cpp
void MainWindow:: toggleSerial(bool checked)
{
      ui->start->setText(ui->start->isChecked() ? "Connect" : "Disconnect");
          if (checked)
          {
              serial->close();
              ui->start->setStyleSheet(QString("QPushButton {background-color: rgb(115, 210, 22);}"));
          }
          else
          {
              ui->start->setStyleSheet(QString("QPushButton {background-color: red;}"));
      
      
                 serial = new QSerialPort(this);
                 serial = new QSerialPort(this);
                 serial->setPortName("ttyUSB0");
                 serial->setBaudRate(QSerialPort::Baud9600);
                 serial->setDataBits(QSerialPort::Data8);
                 serial->setParity(QSerialPort::NoParity);
                 serial->setStopBits(QSerialPort::OneStop);
                 serial->setFlowControl(QSerialPort::NoFlowControl);
      
                 if( serial->open(QIODevice::ReadWrite))
                  {
                      qDebug()<<"Port Open OK";
                      connect(serial, &QSerialPort::readyRead, this, &MainWindow::serialReceived);
                  }
                else
                  {
                      qDebug()<<"Can't Open Port : " << serial->error();
                  }
                 serialReceived();
          }
}
void MainWindow::on_start_toggled(bool checked)
{
    toggleSerial(checked);
}

inside Setup add the signal like @jsulm suggested

signals:
    void onOffSerialPort(bool checked);

connect your button toggle signal (in Setup) to this signal (constructor of Setup

connect(ui->myButton, &QPushButton:: toggled, this, &Setup:: onOffSerialPort);

and finally
connect that onOffSerialPort signal to your toggleSerial slot

connect(setup, &Setup:: onOffSerialPort, this, &MainWindow:: toggleSerial);

one thing to keep in mind, your 2 buttons will now not necessarily show the correct checked status.

I'll let you figure that one out.

[Shivam Sharma]

Error: no member named start in ui::mainwindow,

that is because it isn't able to access the pushbutton from setup window. Help please.

Also:
void MainWindow::on_start_toggled(bool checked)
{
toggleSerial(checked);
}
this also has errors saying: on_start_toggled doesn't match any declaration.

[J.Hilk]

@Shivam-Sharma
where did you put this ?

public slots:
     void toggleSerial(bool checked);

in mainwindow.h or on setup.h ?

[Shivam Sharma]

in mainwindow.h

[jsulm]

@Shivam-Sharma said in Is data received from serial port possible to view on two forms?:

that is because it isn't able to access the pushbutton from setup window

I repeat it once more: YOU DO NOT HAVE TO ACCESS THIS BUTTON FROM MAIN WINDOW!
Please show your current code.

[Shivam Sharma]

//mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <info.h>
#include <setup.h>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
    Info *info;
    Setup *setup;

signals:
    void newSerialData(QString data);

public slots:
        void toggleSerial(bool checked);

private slots:
    void serialReceived();
    void on_infobutton_clicked();
    void on_setupbutton_clicked();

private:
    Ui::MainWindow *ui;

};
#endif // MAINWINDOW_H

//mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <info.h>
#include <setup.h>

#include <QList>
#include <QComboBox>
#include <QString>
#include <QTextEdit>
#include <QTime>
#include <QDebug>
#include <QSerialPort>
#include <QtSerialPort/QSerialPortInfo>
#include <QFile>
#include <qmath.h>
#include <QList>

QSerialPort *serial;
QString line;
QString txt1;
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
       ui->setupUi(this);
       connect(setup, &Setup::onOffSerialPort, this, &MainWindow::toggleSerial);
       serial = new QSerialPort(this);
       serial = new QSerialPort(this);
       serial->setPortName("ttyUSB0");
       serial->setBaudRate(QSerialPort::Baud9600);
       serial->setDataBits(QSerialPort::Data8);
       serial->setParity(QSerialPort::NoParity);
       serial->setStopBits(QSerialPort::OneStop);
       serial->setFlowControl(QSerialPort::NoFlowControl);

       if( serial->open(QIODevice::ReadWrite))
        {
            qDebug()<<"Port Open OK";
            connect(serial, &QSerialPort::readyRead, this, &MainWindow::serialReceived);
        }
      else
        {
            qDebug()<<"Can't Open Port : " << serial->error();
        }
       serialReceived();
}

MainWindow::~MainWindow()
{
    delete ui;
    serial->close();
}

char *get_field(char *str,int fld)
{
    static char t0[512];
    int i=0,j=0,k=0;
    while(i<512)
    {
        if(*(str+i) == ',' || *(str+i) == '\n')
        {
            if (fld==j) return t0;
                j++;
                t0[0]=0;
                k=0;
        }
        else
        {
            t0[k++]=*(str+i);
            t0[k]=0;
        }
        i++;
    }
        t0[0]=0;
        return t0;
}

int checksum_gps(char *str)
{
    unsigned char cs=0,sum=0,i=0;
    char sCS[8], exit =0;

    while (i<250 && !exit)
    {
        if(*(str+i) == '*')
        {
            sum=0;
            break;
        }
        if(sum)
            cs^=*(str+i);
        if(*(str+i) == '$')
            sum=1;
        if(*(str+i) == 0)
            exit=1;
        i++;
    }
    sprintf(sCS,"%02X",cs);
    if (memcmp(sCS,str+i+1,2)==0)
        return 1;
    return 0;
}

char *timestamp(void)
{
    static char t0[128];
    long ms;
    time_t now;
    struct tm *t;
    struct timespec spec;

    time(&now);
    t= localtime(&now);
    clock_gettime(CLOCK_REALTIME, &spec);
    ms= round(spec.tv_nsec/1.0e6);

    sprintf(t0, "%04d/%02d/%02d %02d:%02d:%02d.%03ld ",
            t->tm_year+1900, t->tm_mon+1, t->tm_mday,
            t->tm_hour, t->tm_min, t->tm_sec, ms);
    return t0;
}

void MainWindow::serialReceived()
{
    QByteArray serialData;
    serialData = serial->readAll();
    QString static receivedData = QString::fromStdString(serialData.toStdString());

    char t0[512];
    static char t1[512];
    static int wp=0;
    unsigned int i=0;

    QString filename="/home/user/Desktop/Programs/MainCBOT2/entrydata.txt";
    QFile file( filename );

    if(file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text))
    {
        QTextStream stream( &file );
        strcpy(t0,serialData);
        for (i=0;i<strlen(t0);i++)
        {
            t1[wp++]=t0[i];
            wp%=512;
            t1[wp]=0;

            if(t0[i] == '\n')
            {
                wp=0;
                if(checksum_gps(t1))
                {
                    if(memcmp("$GPRMC",t1,6)==0)
                    {
                        unsigned int latcnt1=0, log_cnt1=0,spdcnt=0, cogcnt=0;
                        char cog[20];
                        char spd[20];
                        char lat1[20], lg1[20];
                        for(i=20;i<28;i++)
                        {
                            lat1[latcnt1++]=t1[i];
                        }
                        float j=atof(lat1);
                        float k=(int)(j/100);
                        float minlat  = j - ( k * 100 );
                        float ddeglat = k + ( minlat / 60 );
                        ui->latitude->setText(QString::number(ddeglat,'f'));

                        for(i=33;i<42;i++)
                        {
                            lg1[log_cnt1++]=t1[i];
                        }
                        float p=atof(lg1);
                        float q=(int)(p/100);
                        float minlong  = p - ( q * 100 );
                        float ddeglong = q + ( minlong / 60 );
                        ui->longitude->setText(QString::number(ddeglong,'f'));

                        for (i=45;i<50;i++)
                        {
                            spd[spdcnt++]=t1[i];
                        }
                        float r=atof(spd);
                        ui->speed->setText(QString::number(r,'f',4));

                        for (i=50;i<56;i++)
                        {
                            cog[cogcnt++]=t1[i];
                        }
                        float u=atof((cog));
                        float w=u*0.514444;
                        ui->cog->setText(QString::number(w,'f',4));

                        stream<<strcat(t1,timestamp());
                        ui->rece->setText(t1);
                        emit newSerialData(t1);
                        fflush(stdout);
                    }
                }
            }
        }
        file.close();
    }
    ui->timest->setText(timestamp());
}

void MainWindow::on_infobutton_clicked()
{
    info = new Info(this);
    info->show();
}

void MainWindow::on_setupbutton_clicked()
{
    setup = new Setup(this);
    setup->show();
    connect(this, &MainWindow::newSerialData, setup, &Setup::onNewSerialData);
}

void MainWindow:: toggleSerial(bool checked)
{
          ui->start->setText(ui->start->isChecked() ? "Connect" : "Disconnect");
          if (checked)
          {
              serial->close();
             ui->start->setStyleSheet(QString("QPushButton {background-color: rgb(115, 210, 22);}"));
          }
          else
          {
              ui->start->setStyleSheet(QString("QPushButton {background-color: red;}"));

                 serial = new QSerialPort(this);
                 serial = new QSerialPort(this);
                 serial->setPortName("ttyUSB0");
                 serial->setBaudRate(QSerialPort::Baud9600);
                 serial->setDataBits(QSerialPort::Data8);
                 serial->setParity(QSerialPort::NoParity);
                 serial->setStopBits(QSerialPort::OneStop);
                 serial->setFlowControl(QSerialPort::NoFlowControl);

                 if( serial->open(QIODevice::ReadWrite))
                  {
                      qDebug()<<"Port Open OK";
                      connect(serial, &QSerialPort::readyRead, this, &MainWindow::serialReceived);
                  }
                else
                  {
                      qDebug()<<"Can't Open Port : " << serial->error();
                  }
                 serialReceived();
          }
}

void MainWindow::on_start_toggled(bool checked)
{
    toggleSerial(checked);
}

//setup.h

#ifndef SETUP_H
#define SETUP_H
#include <QDialog>

namespace Ui {
class Setup;
}

class Setup : public QDialog
{
    Q_OBJECT

public:
    explicit Setup(QWidget *parent = nullptr);
    ~Setup();

public slots:
     void onNewSerialData(QString data);

signals:
      void onOffSerialPort(bool checked);

private:
    Ui::Setup *ui;
};

#endif // SETUP_H

//setup.cpp

#include "setup.h"
#include "ui_setup.h"
#include <QSerialPortInfo>
#include <QFile>
#include <QSerialPort>

Setup::Setup(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Setup)
{
    ui->setupUi(this);
    ui->start->setCheckable(true);
    connect(ui->start, &QPushButton::toggled, this, &Setup::onOffSerialPort);

    QList<QSerialPortInfo> list;
    list = QSerialPortInfo::availablePorts();

    for (int i= 0; i < list.length(); i++)
    {
        ui->comboBox->addItem(list[i].portName());
    }

    ui->baudratebox->setInsertPolicy(QComboBox::NoInsert);
    ui->baudratebox->addItem(QStringLiteral("9600"), QSerialPort::Baud9600);
    ui->baudratebox->addItem(QStringLiteral("19200"), QSerialPort::Baud19200);
    ui->baudratebox->addItem(QStringLiteral("38400"), QSerialPort::Baud38400);
    ui->baudratebox->addItem(QStringLiteral("115200"), QSerialPort::Baud115200);
}

Setup::~Setup()
{
    delete ui;
}

void Setup::onNewSerialData(QString data)
{
     ui->receiver->append(data);
}

[J.Hilk]

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
       ui->setupUi(this);
       connect(setup, &Setup::onOffSerialPort, this, &MainWindow::toggleSerial);

the connect here is wrong, I think I said, you should place it where you create (new Setup(this)) the setup object.

that would be here

void MainWindow::on_setupbutton_clicked()
{
    setup = new Setup(this);
    setup->show();
    connect(this, &MainWindow::newSerialData, setup, &Setup::onNewSerialData);
}

Error: no member named start in ui::mainwindow,

We don't see the form (.ui) class of MainWindow did you change the object name of start there ?

---

Edit: you also removed the on_start_toggled declaration in MainWindow.h

you know what, the "ConnectByName" feature is crap anyway don't use it.
Remove on_start_toggled complete,
and add the following in the mainWindow constructor :

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
       ui->setupUi(this);
       connect(ui->start, &QPushButton::toggled, this, &MainWindow::toggleSerial);

[JonB]

@Shivam-Sharma said in Is data received from serial port possible to view on two forms?:

Also:
void MainWindow::on_start_toggled(bool checked)
{
toggleSerial(checked);
}
this also has errors saying: on_start_toggled doesn't match any declaration.

You need to do what it says. Where is your declaration of this method in the .h file? I think you had it in setup.h, if you've moved the method to MainWindow then obviously you need to move the declaration too.

[Shivam Sharma]

This post is deleted!

[J.Hilk]

I think there was a miss conception, start is not a toggle button, but a QLabel or something.

Anyway here's a working example

https://github.com/DeiVadder/Topic111960

btw, you leak memory (class instances) all over the place.