serial port

[Rockerz]

I created two pages in qt c++ (main window.cpp , test.cpp) in first page using serial port connected and clicked test page serial port disconnected what is the reason and how to fix this issue

Test * page1;
page1 = new Test(this);
void MainWindow::on_next_page_clicked()
{ 
this->hide();
page1->show();
}

[JonB]

@Rockerz
Your code shows nothing about how you attempt to use serial port or share it across pages so nobody can answer. Hiding windows does not affect serial port.

[Rockerz]

@JonB ```
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "test.h"
Test * page1;
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
ui.setupUi(this);
page1 = new Test(this);

serial_init();

}
void MainWindow::serial_init()
{
foreach (const QSerialPortInfo &info, QSerialPortInfo::availablePorts())
{
Value = info.portName();
ui->comboBox->addItem(Value);
ui->comboBox->setCurrentIndex(0);
}
}

void MainWindow::readData()
{

QByteArray data = serial->readAll();
QString receivedData = QString::fromLocal8Bit(data);
ui->plainTextEdit->insertPlainText(receivedData);

}
void MainWindow::on_connect_clicked()
{
if (isConnected)
{
serial->close();

    ui->radioButton->setStyleSheet("QRadioButton::indicator { background-color: RED; width: 10px; height: 10px; border-radius: 5px;}");

    ui->radioButton->setText("DEVICE NOT CONNECTED !");

    isConnected = false;
    ui->connect->setText("CONNECT");
}
else
{
    ui->radioButton->setStyleSheet("QRadioButton::indicator { background-color: green; width: 10px; height: 10px; border-radius: 5px;}");
    ui->radioButton->setText("DEVICE CONNECTED");
    serial = new QSerialPort(ui->comboBox->currentText());
    serial->setBaudRate(QSerialPort::Baud115200);
    serial->setDataBits(QSerialPort::Data8);
    serial->setParity(QSerialPort::NoParity);
    serial->setStopBits(QSerialPort::OneStop);
    serial->setFlowControl(QSerialPort::NoFlowControl);

    if (serial->open(QIODevice::ReadWrite))
    {
        ui->label->setText("DEVICE CONNECTED");         
        ui->connect->setText("DISCONNECT");

        connect(serial, SIGNAL(readyRead()), this, SLOT(readData()));
    }
}

}

void MainWindow::on_next_page_clicked()
{
this->hide();
page1->show();
}

[jsulm]

@Rockerz How do you know "serial port disconnected"? I don't see anything in the code you posted.
And please format your code properly using code tags, it is hard to read what you posted.

One more thing: in void MainWindow::on_connect_clicked() you create a new QSerialPort everytime you do a new connection, you do not delte the old instance -> memory leak.

[Rockerz]

@jsulm When I run this code switching test page and return to main window page device disconnected message I saw and How to fix this issue and in this page. In mainwindow serial used test page serial 1 is used it work or not because I'm getting error when used serial.

#include "Test.h"
#include "ui_Test.h"
#include "mainwindow.h"
QSerialPort * serial1;
int check1 =0, values1;

Test::Test(QWidget *parent) :
   QMainWindow(parent),
   ui(new Ui::Test)
{
   ui->setupUi(this);


   ui->Test_linEdit->setValidator(new QIntValidator(this));
   ui->Test_linEdit->setMaxLength(5);
}

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

void Test::on_Send_Ref_clicked()
{
   QByteArray ref_burn;
   ref_burn = ui->Test_linEdit->text().toUtf8();

   QByteArray bytes;
   bytes.resize(1);
   bytes[0] = '#';
   bytes[1] = 'B';
   bytes[2] = 'T';
   bytes[3] = '=';
   bytes[4] = '0';
   bytes[5] = QString::number(values1).toUtf8()[0];
   bytes[6] = QString::number(values1).toUtf8()[1];
   bytes[7] = QString::number(values1).toUtf8()[2];
   bytes[8] = QString::number(values1).toUtf8()[3];
   bytes[9] = '!';
   serial1->write(bytes);

   qDebug()<<"Reference Test "<<bytes;

}

void Test::on_back_clicked()
{
   this->hide();
   MainWindow *page1 = new MainWindow();
   page1->show();
}


void Test::on_exit_clicked()
{
   this->close();
}

[jsulm]

@Rockerz said in serial port:

void Test::on_back_clicked()
{
this->hide();
MainWindow *page1 = new MainWindow();
page1->show();
}

Why are you creating a new MainWindow here?!

[Rockerz]

@jsulm how to write back to main window ? provide me a idea for back to main window

[jsulm]

@Rockerz said in serial port:

how to write back to main window ?

Using signals/slots...

[Rockerz]

@jsulm I'm not still get your point what should I give in signals?

[JonB]

@Rockerz
In a signal you create for this purpose you should pass as (a) parameter(s) whatever information you want to pass, e.g. a string you want displayed. A slot you write in your existing main window should receive that string and do whatever on the UI side, such as displaying it.

You need to understand conceptually why creating a new MainWindow() will never be right and will never address your existing main window instance.