Create a SerialPortReader and a Chart in the same main function

Denta1000

Hi,

I want to create a splinechart whose series is built from serialport datas.
My serialport part is running well. The SerialPortReader is called in the main.

But when I try to create a QMainWindow in the main, the application will wether stop, wether display "QWidget: Cannot create a QWidget without QApplication"

So my question is : Can I create a second application in the main and associate it with the window ?

Or can I create the chart in the same application as the SerialPort ?

Thanks for your help

nagesh

@Denta1000

So my question is : Can I create a second application in the main and associate it with the window ?

As the problem statement says "reading the data from serial port and displaying in the splinechart", it is better to have single application integrated with both the features.

Or can I create the chart in the same application as the SerialPort ?

Yes, Have you implemented the features and facing any issues?

Denta1000

@nagesh

Here is my main function :

#include "serialportreader.h"
//#include "themewidget.h"
#include <QCoreApplication>
#include <QSerialPort>
#include <QStringList>
#include <QTextStream>
#include <QDebug>
#include <QLine>
#include <QtWidgets>
#include <QtCharts>
#include <QVector>

int main(int argc, char *argv[])
{
    QCoreApplication coreApplication(argc, argv);
    const int argumentCount = QCoreApplication::arguments().size();
    const QStringList argumentList = QCoreApplication::arguments();

    QTextStream standardOutput(stdout);

    if (argumentCount == 1) {
        standardOutput << QObject::tr("Usage: %1 <serialportname> [baudrate]")
                          .arg(argumentList.first())
                       << "\n";
        return 1;
    }

    DataTable data_test(nullptr);

    QSerialPort serialPort;
    const QString serialPortName = argumentList.at(1);
    serialPort.setPortName(serialPortName);

    const int serialPortBaudRate = (argumentCount > 2)
            ? argumentList.at(2).toInt() : QSerialPort::Baud9600;
    serialPort.setBaudRate(serialPortBaudRate);

//  Test perso
    qDebug() << "Connection " << serialPortName << "succeeded , baudrate : " << serialPortBaudRate << "\n";

//
    if (!serialPort.open(QIODevice::ReadOnly)) {
        standardOutput << QObject::tr("Failed to open port %1, error: %2")
                          .arg(serialPortName)
                          .arg(serialPort.errorString())
                       << "\n";
        return 1;
    }

    QMainWindow window;
    QChart *chart = new QChart;
    chart->setTitle("Dynamic spline chart");
    chart->legend()->hide();
    chart->setAnimationOptions(QChart::AllAnimations);
    QChartView chartView(chart);
    chartView.setRenderHint(QPainter::Antialiasing);
    window.setCentralWidget(&chartView);
    window.resize(400, 300);
    window.show();

    qDebug() << "Initiating SerialPortReader \n";
    SerialPortReader serialPortReader(&serialPort, &data_test);
    //serial_start(&serialPort, &coreApplication);

    qDebug() << "Exit Serialport \n";

    /*while(1)
    {
        series->append(data_test.temps[data_test.temps.size()-1], data_test.altitude[data_test.temps.size()-1]);
    }*/

    return coreApplication.exec();
}

When the application reach the QMainWindow window line, it blocks and stop the application. So I wondered if the two Objects (chart and serialport) are able to run at the same time ?

JonB

@Denta1000 said in Create a SerialPortReader and a Chart in the same main function:

QCoreApplication coreApplication(argc, argv);

When the application reach the QMainWindow window line, it blocks and stop the application.

https://doc.qt.io/qt-5/qcoreapplication.html#details

The QCoreApplication class provides an event loop for Qt applications without UI.

Is this a wise choice when you want a QMainWindow/QChartView?

Denta1000

@JonB

In fact, I needed a QApplication and not a QcoreApplication , as the error message said...
Thanks for you help