CODEWITHSUNDEEP
c++qtsocketsqtcpsocket
Ryan
Ryan

Reputation: 279

How to let QTcpsocket remain connection after closing DialogWindow?

In my Qt application, I have a MainWindow and a DialogWindow. The DialogWindow is for setting up server's IP address and port. While MainWindow is for performing communication after successful connection.

However, setting up QTcpSocket *socket in DialogWindow means that when I close DialogWindow, the socket will be destroyed, thus the socket will be disconnected with the server.

I would like to keep the socket connected to the server after the DialogWindow was closed. Are there any methods that can achieve this result？

Please give me some comments and ideas on this. I am quite a newbie to Qt.

DialogSetup.cpp

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

    socket = new QTcpSocket(this);
    connect(socket, SIGNAL(connected()),this, SLOT(wasconnected()));
    connect(socket,SIGNAL(disconnected()),this,SLOT(wasdisconnected()));
}
DialogSetup::~DialogSetup()
{
    delete ui;
}

void DialogSetup::on_pushButtonConnect_clicked()
{
    m_strIPAdd = ui->lineEditIPAdd->text();
    m_strPort = ui->lineEditPort->text().toInt();

    socket->connectToHost(m_strIPAdd,m_strPort);

    if(!socket->waitForConnected(10000))
    {
       ui->labelStatus->setText("Error");
       QMessageBox::information(this,"Error",socket->errorString());
    }
}
void DialogSetup::wasconnected()
{
    socket->write("Hello server!");
    ui->labelStatus->setText("Connected!");
    ui->pushButtonDisconnect->setDisabled(false);
}

void DialogSetup::wasdisconnected()
{
    ui->labelStatus->setText("Disonnected!");
}

void DialogSetup::on_pushButtonDisconnect_clicked()
{
    socket->close();
}

Mainwindow.cpp

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

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

void MainWindow::on_actionSetup_triggered()
{
    dialogsetup = new DialogSetup(this);
    dialogsetup->show();
}

Upvotes: 0

Views: 624

Answers (2)

Sommerwild
Sommerwild

Reputation: 548

Move the socket outside the dialog class. Something like that:

void MainWindow::on_actionSetup_triggered()
{
    socket = new QTcpSocket(this); //declared as private in MainWindow
    dialogsetup = new DialogSetup(socket, this);
    connect(socket,SIGNAL(connected()), dialogsetup, SLOT(wasconnected()));
    connect(socket,SIGNAL(disconnected()), dialogsetup ,SLOT(wasdisconnected()));
    dialogsetup->show();
}

The dialog class stores a pointer to the socket and operates with it:

DialogSetup::DialogSetup(QTcpSocket *socket, QWidget *parent) :
    QDialog(parent),
    socket_(socket),
    ui(new Ui::DialogSetup)
{
    ui->setupUi(this);
}

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

void DialogSetup::on_pushButtonConnect_clicked()
{
    m_strIPAdd = ui->lineEditIPAdd->text();
    m_strPort = ui->lineEditPort->text().toInt();

    socket_->connectToHost(m_strIPAdd,m_strPort);

    if(!socket_->waitForConnected(10000))
    {
       ui->labelStatus->setText("Error");
       QMessageBox::information(this,"Error",socket->errorString());
    }
}
void DialogSetup::wasconnected()
{
    socket_->write("Hello server!");
    ui->labelStatus->setText("Connected!");
    ui->pushButtonDisconnect->setDisabled(false);
}

void DialogSetup::wasdisconnected()
{
    ui->labelStatus->setText("Disonnected!");
}

void DialogSetup::on_pushButtonDisconnect_clicked()
{
    socket_->close();
}

Upvotes: 2

Amartel
Amartel

Reputation: 4286

Change it's parent, or remove parent at all (though, you'll have to delete socket manually).

But, a better solution would be - not to create socket in dialog, but to pass it there:

DialogSetup::DialogSetup(QTcpSocket *socket_, QWidget *parent) :
    QDialog(parent),
    ui(new Ui::DialogSetup),
    socket(socket_)

...

void MainWindow::on_actionSetup_triggered()
{
    dialogsetup = new DialogSetup(socket, this);
    dialogsetup->show();
}

Upvotes: 0

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