QTcpSocket based client : QTcpSocket « Qt « C++

1. C++
2. Qt
3. QTcpSocket

QTcpSocket based client

  

#ifndef CLIENT_H
#define CLIENT_H

#include <QDialog>
#include <QTcpSocket>

QT_BEGIN_NAMESPACE
class QDialogButtonBox;
class QLabel;
class QLineEdit;
class QPushButton;
class QTcpSocket;
QT_END_NAMESPACE

class Client : public QDialog
{
    Q_OBJECT

public:
    Client(QWidget *parent = 0);

private slots:
    void requestNewFortune();
    void readFortune();
    void displayError(QAbstractSocket::SocketError socketError);
    void enableGetFortuneButton();

private:
    QLabel *hostLabel;
    QLabel *portLabel;
    QLineEdit *hostLineEdit;
    QLineEdit *portLineEdit;
    QLabel *statusLabel;
    QPushButton *getFortuneButton;
    QPushButton *quitButton;
    QDialogButtonBox *buttonBox;

    QTcpSocket *tcpSocket;
    QString currentFortune;
    quint16 blockSize;
};


#endif





#include <QtGui>
#include <QtNetwork>

#include "client.h"

Client::Client(QWidget *parent): QDialog(parent)
{
    hostLabel = new QLabel(tr("&Server name:"));
    portLabel = new QLabel(tr("S&erver port:"));

    hostLineEdit = new QLineEdit("Localhost");
    portLineEdit = new QLineEdit;
    portLineEdit->setValidator(new QIntValidator(1, 65535, this));

    hostLabel->setBuddy(hostLineEdit);
    portLabel->setBuddy(portLineEdit);

    statusLabel = new QLabel(tr("This examples requires that you run the "
                                "Fortune Server example as well."));

    getFortuneButton = new QPushButton(tr("Get Fortune"));
    getFortuneButton->setDefault(true);
    getFortuneButton->setEnabled(false);

    quitButton = new QPushButton(tr("Quit"));

    buttonBox = new QDialogButtonBox;
    buttonBox->addButton(getFortuneButton, QDialogButtonBox::ActionRole);
    buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole);


    tcpSocket = new QTcpSocket(this);

    connect(hostLineEdit, SIGNAL(textChanged(const QString &)),this, SLOT(enableGetFortuneButton()));
    connect(portLineEdit, SIGNAL(textChanged(const QString &)),this, SLOT(enableGetFortuneButton()));
    connect(getFortuneButton, SIGNAL(clicked()),this, SLOT(requestNewFortune()));
    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
    connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readFortune()));
    connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),this, SLOT(displayError(QAbstractSocket::SocketError)));

    QGridLayout *mainLayout = new QGridLayout;
    mainLayout->addWidget(hostLabel, 0, 0);
    mainLayout->addWidget(hostLineEdit, 0, 1);
    mainLayout->addWidget(portLabel, 1, 0);
    mainLayout->addWidget(portLineEdit, 1, 1);
    mainLayout->addWidget(statusLabel, 2, 0, 1, 2);
    mainLayout->addWidget(buttonBox, 3, 0, 1, 2);
    setLayout(mainLayout);

    setWindowTitle(tr("Fortune Client"));
    portLineEdit->setFocus();
}
void Client::requestNewFortune()
{
    getFortuneButton->setEnabled(false);
    blockSize = 0;
    tcpSocket->abort();
    tcpSocket->connectToHost(hostLineEdit->text(),
                             portLineEdit->text().toInt());
}
void Client::readFortune()
{
    QDataStream in(tcpSocket);
    in.setVersion(QDataStream::Qt_4_0);

    if (blockSize == 0) {
        if (tcpSocket->bytesAvailable() < (int)sizeof(quint16))
            return;
        in >> blockSize;
    }

    if (tcpSocket->bytesAvailable() < blockSize)
        return;
    QString nextFortune;
    in >> nextFortune;

    if (nextFortune == currentFortune) {
        QTimer::singleShot(0, this, SLOT(requestNewFortune()));
        return;
    }
    currentFortune = nextFortune;
    statusLabel->setText(currentFortune);
    getFortuneButton->setEnabled(true);
}
void Client::displayError(QAbstractSocket::SocketError socketError)
{
    switch (socketError) {
    case QAbstractSocket::RemoteHostClosedError:
        break;
    case QAbstractSocket::HostNotFoundError:
        QMessageBox::information(this, tr("Fortune Client"),
                                 tr("The host was not found. Please check the "
                                    "host name and port settings."));
        break;
    case QAbstractSocket::ConnectionRefusedError:
        QMessageBox::information(this, tr("Fortune Client"),
                                 tr("The connection was refused by the peer. "
                                    "Make sure the fortune server is running, "
                                    "and check that the host name and port "
                                    "settings are correct."));
        break;
    default:
        QMessageBox::information(this, tr("Fortune Client"),
                                 tr("The following error occurred: %1.")
                                 .arg(tcpSocket->errorString()));
    }

    getFortuneButton->setEnabled(true);
}
void Client::enableGetFortuneButton(){
    getFortuneButton->setEnabled(!hostLineEdit->text().isEmpty()
                                 && !portLineEdit->text().isEmpty());
}





#include <QApplication>

#include "client.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Client client;
    client.show();
    return client.exec();
}

   
    
  

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