using QTextStream to write in textfile, what is copied after enable the the line to copy is not what I have with qDebug we the line disable

filipdns

Hello,

I want to record temp from sensor and Arduino and I need to add date from theses data.

for that I try:

void MainWindow::readData(const QByteArray &data)
{
    QFile fileOut("d:/Magasin_Temp_Hygro.txt");
    fileOut.open(QFile::ReadWrite);
    QTextStream streamOut(&fileOut);
    const QChar delimeter = ';' ;
    QStringList list = streamOut.readAll().split(delimeter);
    QString line=fileOut.readLine();
    streamOut <<data;
    fileOut.close();
    countLine();
}
void MainWindow::countLine()
{
    QFile fileOut("d:/Magasin_Temp_Hygro.txt");
    fileOut.open(QFile::ReadWrite);
    int count=0;
    while (!fileOut.atEnd())
    {
        QString line=fileOut.readLine();
        count++;
        //qDebug()<<"count "<<count;
    }
    dating(count);
}
void MainWindow::dating(int count)
{
QFile fileOut("d:/Magasin_Temp_Hygro.txt");
    fileOut.open(QFile::ReadWrite);
    QTextStream streamOut(&fileOut);
    QDateTime timestamp;
    int count2=0;
    QString linetowrite;
    while (!streamOut.atEnd())
    {
        QString line=streamOut.readLine();
        count2++;
        if(count2==count-1)
        {
            QStringList text=streamOut.readAll().split(";");
            QString time;
            QString line2;
            line2=streamOut.readLine();
            QString text2=text[0];
            timestamp=QDateTime::currentDateTime();
            time=timestamp.toString("dd/MM/yy hh'h'mm");
            linetowrite=time+text2;
        }
qDebug()<<"linetowrite "<<linetowrite;
//streamOut <<linetowrite;
    }
    fileOut.close();
}

with this with qDebug, I have on console:

linetowrite  "06/05/19 18h30:Temperature:21.9"

but if I remove // from the line at the end of my code on to write the value of linetowrite to the file:

streamOut <<linetowrite;

it's writing on console log and in the file:

06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidi06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidity:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidi06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidity:29.0006/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidi06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidity:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidi06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.906/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:206/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperatu06/05/19 18h30:T06/05/19 18h30:Tempe06/05/19 18h30:T06/05/19 18h30:Temperature:21.90:Humidity:29.00"

I don't understand what happen with my code, may be problem with QTextStream ...

Thank you for your help

Christian Ehrlicher

You're writing to a file and after you've written something you read from it and you do this in a loop - what do you expect?
Don't read and write to a file at the same time.

filipdns

@Christian-Ehrlicher hello, yes, I have to read the last ligne then add date time to it and write the result to the file

jsulm

@filipdns Don't read and write same file at same time!
Read from original file, write to a temporary file, when finished delete the original file and rename the temporary file to the same name as original file...

filipdns

@jsulm yesy that solve my problem, thanks a lot

I share my last code in case it can help

/****************************************************************************
**
** Copyright (C) 2012 Denis Shienkov <denis.shienkov@gmail.com>
** Copyright (C) 2012 Laszlo Papp <lpapp@kde.org>
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtSerialPort module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "console.h"
#include "settingsdialog.h"
#include <QDebug>
#include <QLabel>
#include <QMessageBox>
#include <QSystemTrayIcon>
#include <QIcon>
#include <QPixmap>
#include <QFileInfo>
#include <QDateTime>
#include <QByteArray>
#include <QtCharts/QChartView>
#include <QtCharts/QLineSeries>
#include <QtCharts/QValueAxis>
#include <QtCharts/QCategoryAxis>
#include <QtGui/QMouseEvent>
#include <QKeyEvent>
#include <QStackedWidget>

QT_CHARTS_USE_NAMESPACE
//! [0]
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    m_ui(new Ui::MainWindow),
    m_status(new QLabel),
    m_console(new Console),
    m_settings(new SettingsDialog),
    m_serial(new QSerialPort(this))
  //! [1]
{
    //! [0]
    m_ui->setupUi(this);
    //m_console->setEnabled(false);
    setCentralWidget(chartView);

    m_ui->actionConnect->setEnabled(true);
    m_ui->actionDisconnect->setEnabled(false);
    m_ui->actionQuit->setEnabled(true);
    m_ui->actionConfigure->setEnabled(true);
    m_ui->actionGraph->setEnabled(true);
    m_ui->statusBar->addWidget(m_status);
line_count=0;
hygro=0;
temp=0;
    chart->addSeries(temperature);
    chart->addSeries(hygrometrie);

    temperature->attachAxis(axisX);
    temperature->attachAxis(axisYtemp);

    hygrometrie->attachAxis(axisX);
    hygrometrie->attachAxis(axisYhygro);

    axisX->setLabelsAngle(-90);
    axisX->setStartValue(0);
    axisX->setRange(0,500);
    axisX->setLabelsPosition(QCategoryAxis::AxisLabelsPositionOnValue);

    axisYtemp->setLabelsPosition(QCategoryAxis::AxisLabelsPositionOnValue);
    axisYtemp->setMin(10);
    axisYtemp->setMax(50);
    axisYtemp->setGridLineVisible(true);
    axisYtemp->setTickCount(10);
    axisYtemp->setLabelsColor(temperature->pen().color());

    axisYhygro->setLabelsPosition(QCategoryAxis::AxisLabelsPositionOnValue);
    axisYhygro->setMin(10);
    axisYhygro->setMax(100);
    axisYhygro->setTickCount(10);
    axisYhygro->setGridLineVisible(true);
    axisYhygro->setLabelsColor(hygrometrie->pen().color());

    chart->addAxis(axisYhygro, Qt::AlignRight);
    chart->addAxis(axisYtemp, Qt::AlignLeft);
    chart->addAxis(axisX, Qt::AlignBottom);
    chart->setTitle("Revelé Température et humidité Magasin");
    chartView->setRenderHint(QPainter::Antialiasing);
    chartView->chart()->setAxisX(axisX, hygrometrie);
    chartView->chart()->setAxisX(axisX, temperature);
    chartView->chart()->setAxisY(axisYtemp, temperature);
    chartView->chart()->setAxisY(axisYhygro, hygrometrie);
    chartView->setRenderHint(QPainter::Antialiasing);

    QFile fileOut("d:/Magasin_Temp_Hygro.txt");//select text file with recorded data
    fileOut.open(QIODevice::ReadWrite | QIODevice::Text);
    initActionsConnections();

    connect(m_serial, &QSerialPort::errorOccurred, this, &MainWindow::handleError);
    connect(m_serial, &QSerialPort::readyRead, this, &MainWindow::on_actionGraph);
}

MainWindow::~MainWindow()
{
    delete m_settings;
    delete m_ui;
}

//! [4]
void MainWindow::openSerialPort()
{
    const SettingsDialog::Settings p = m_settings->settings();
    m_serial->setPortName(p.name);
    m_serial->setBaudRate(p.baudRate);
    m_serial->setDataBits(QSerialPort::Data8);
    m_serial->setParity(QSerialPort::NoParity);
    m_serial->setStopBits(QSerialPort::OneStop);
    m_serial->setFlowControl(QSerialPort::NoFlowControl);
    if (m_serial->open(QIODevice::ReadOnly)) {
        //m_console->setEnabled(true);
        // m_console->setLocalEchoEnabled(p.localEchoEnabled);
        m_ui->actionConnect->setEnabled(false);
        m_ui->actionDisconnect->setEnabled(true);
        m_ui->actionConfigure->setEnabled(false);
        m_ui->actionGraph->setEnabled(true);
        m_ui->actionData->setEnabled(false);
        showStatusMessage(tr("Connected to %1 : %2, %3")
                          .arg(p.name).arg(p.stringBaudRate).arg(p.stringDataBits));
    } else {
        QMessageBox::critical(this, tr("Error"), m_serial->errorString());

        showStatusMessage(tr("Open error"));
    }
    tray = new QSystemTrayIcon(this);

    icon.addFile(":/images/disconnect.png");
    tray->setIcon(icon);
    tray->setVisible(true);
    tray->show();
}

void MainWindow::closeSerialPort()
{
    if (m_serial->isOpen())
        m_serial->close();
    m_console->setEnabled(false);
    m_ui->actionConnect->setEnabled(true);
    m_ui->actionDisconnect->setEnabled(false);
    m_ui->actionConfigure->setEnabled(true);
    showStatusMessage(tr("Disconnected"));
}

void MainWindow::about()
{
    QMessageBox::about(this, tr("About Simple Terminal"),
                       tr("The <b>Simple Terminal</b> example demonstrates how to "
                          "use the Qt Serial Port module in modern GUI applications "
                          "using Qt, with a menu bar, toolbars, and a status bar."));
}

void MainWindow::readData(const QByteArray &data)
{
    QFile fileOut("d:/Magasin_Temp_Hygro.txt");
    fileOut.open(QIODevice::ReadWrite | QIODevice::Text);
    QTextStream streamOut(&fileOut);
    QString delimiter=QString(data.at(data.size()-1));
    if(delimiter==";")
    {
        QStringList result=streamOut2.split(";");
        QString list = streamOut.readLine();
        QDateTime timestamp;
        timestamp=QDateTime::currentDateTime();
        QString time=timestamp.toString("dd/MM/yy hh'h'mm");
        streamOut2=time+" "+streamOut2.replace("\n","").replace("\r","");
        if(streamOut2.size()<100)
        {streamOut <<streamOut2.split(";")[0]+"\n";}
        streamOut2="";
        fileOut.copy("d:/Magasin_Temp_Hygro.txt","d:/Temp_Hygro.txt");
    }else{
        streamOut2=streamOut2+QString(data);
    }
    fileOut.close();
}

void MainWindow::handleError(QSerialPort::SerialPortError error)
{
    if (error == QSerialPort::ResourceError) {
        QMessageBox::critical(this, tr("Critical Error"), m_serial->errorString());
        closeSerialPort();
    }
}
//! [8]

void MainWindow::initActionsConnections()
{
    connect(m_ui->actionConnect, &QAction::triggered, this, &MainWindow::openSerialPort);
    connect(m_ui->actionDisconnect, &QAction::triggered, this, &MainWindow::closeSerialPort);
    connect(m_ui->actionQuit, &QAction::triggered, this, &MainWindow::close);
    //connect(m_ui->actionGraph, &QAction::triggered, this, &MainWindow::closeSerialPort);
    connect(m_ui->actionGraph, &QAction::triggered, this, &MainWindow::on_actionGraph);
    connect(m_ui->actionData, &QAction::triggered, this, &MainWindow::toconsole);
    connect(m_ui->actionData, &QAction::triggered, this, &MainWindow::openSerialPort);
    connect(m_ui->actionConfigure, &QAction::triggered, m_settings, &SettingsDialog::show);
    connect(m_ui->actionClear, &QAction::triggered, m_console, &Console::clear);
    connect(m_ui->actionAbout, &QAction::triggered, this, &MainWindow::about);
    connect(m_ui->actionAboutQt, &QAction::triggered, qApp, &QApplication::aboutQt);
    //connect(qApp,SIGNAL(aboutToQuit()),this,SLOT(quitMyApp()));
}
void MainWindow::keyPressEvent (QKeyEvent *event)
{
    //QKeyEvent *keyEvent = static_cast<QKeyEvent *>(keyEvent);

    if(event->key()==Qt::Key_Plus)
    {chartView->chart()->zoomIn();}
    if(event->key()==Qt::Key_Minus)
    {chartView->chart()->zoomOut();}
    if(event->key()==Qt::Key_4)
    {chartView->chart()->scroll(-10, 0);}
    if(event->key()==Qt::Key_6)
    {chartView->chart()->scroll(10, 0);}
    if(event->key()==Qt::Key_8)
    {chartView->chart()->scroll(0, 10);}
    if(event->key()==Qt::Key_2)
    {chartView->chart()->scroll(0, -10);}
}
void MainWindow::showStatusMessage(const QString &message)
{
    m_status->setText(message);

}

void MainWindow::on_actionGraph()
{

    chartView->repaint();
    QFile fileOut("d:/Temp_Hygro.txt");
    fileOut.open(QIODevice::ReadWrite | QIODevice::Text);


    while( !fileOut.atEnd())//loop until end of QTextStrem
    {
            QString line=fileOut.readLine();
            if(line.size()>=51)
            {
                date=line.split(":")[0];
            bool ok = false;
            temp=line.split(":")[2].toDouble(&ok);
            hygro=line.split(":")[4].replace(";","").toDouble(&ok);
            axisX->append(date,line_count);
            axisYtemp->append(QString::number(temp),temp);
            axisYhygro->append(QString::number(hygro),hygro);

            temperature->append(line_count,temp);
            qDebug()<<line_count<<" "<<temp;

            hygrometrie->append(line_count,hygro);


            }
            line_count++;

    }
line_count=0;
    fileOut.close();
    fileOut.remove();
    const QByteArray data= m_serial->readAll();
    readData(data);
}


void MainWindow::toconsole()
{

    m_ui->actionGraph->setEnabled(true);
    m_ui->actionData->setEnabled(false);
    m_console->setEnabled(true);
    on_actionData();
}
void MainWindow::on_actionData()
{

    const QByteArray data= m_serial->readAll();
    readData(data);
}