dialog.cpp Example File

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#include <QtWidgets> #include <QtNetwork> #include "dialog.h" static const int TotalBytes = 50 * 1024 * 1024; static const int PayloadSize = 64 * 1024; // 64 KB Dialog::Dialog(QWidget *parent) : QDialog(parent) { clientProgressBar = new QProgressBar; clientStatusLabel = new QLabel(tr("Client ready")); serverProgressBar = new QProgressBar; serverStatusLabel = new QLabel(tr("Server ready")); startButton = new QPushButton(tr("&Start")); quitButton = new QPushButton(tr("&Quit")); buttonBox = new QDialogButtonBox; buttonBox->addButton(startButton, QDialogButtonBox::ActionRole); buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole); connect(startButton, SIGNAL(clicked()), this, SLOT(start())); connect(quitButton, SIGNAL(clicked()), this, SLOT(close())); connect(&tcpServer, SIGNAL(newConnection()), this, SLOT(acceptConnection())); connect(&tcpClient, SIGNAL(connected()), this, SLOT(startTransfer())); connect(&tcpClient, SIGNAL(bytesWritten(qint64)), this, SLOT(updateClientProgress(qint64))); connect(&tcpClient, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError))); QVBoxLayout *mainLayout = new QVBoxLayout; mainLayout->addWidget(clientProgressBar); mainLayout->addWidget(clientStatusLabel); mainLayout->addWidget(serverProgressBar); mainLayout->addWidget(serverStatusLabel); mainLayout->addStretch(1); mainLayout->addSpacing(10); mainLayout->addWidget(buttonBox); setLayout(mainLayout); setWindowTitle(tr("Loopback")); } void Dialog::start() { startButton->setEnabled(false); #ifndef QT_NO_CURSOR QApplication::setOverrideCursor(Qt::WaitCursor); #endif bytesWritten = 0; bytesReceived = 0; while (!tcpServer.isListening() && !tcpServer.listen()) { QMessageBox::StandardButton ret = QMessageBox::critical(this, tr("Loopback"), tr("Unable to start the test: %1.") .arg(tcpServer.errorString()), QMessageBox::Retry | QMessageBox::Cancel); if (ret == QMessageBox::Cancel) return; } serverStatusLabel->setText(tr("Listening")); clientStatusLabel->setText(tr("Connecting")); tcpClient.connectToHost(QHostAddress::LocalHost, tcpServer.serverPort()); } void Dialog::acceptConnection() { tcpServerConnection = tcpServer.nextPendingConnection(); connect(tcpServerConnection, SIGNAL(readyRead()), this, SLOT(updateServerProgress())); connect(tcpServerConnection, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError))); serverStatusLabel->setText(tr("Accepted connection")); tcpServer.close(); } void Dialog::startTransfer() { // called when the TCP client connected to the loopback server bytesToWrite = TotalBytes - (int)tcpClient.write(QByteArray(PayloadSize, '@')); clientStatusLabel->setText(tr("Connected")); } void Dialog::updateServerProgress() { bytesReceived += (int)tcpServerConnection->bytesAvailable(); tcpServerConnection->readAll(); serverProgressBar->setMaximum(TotalBytes); serverProgressBar->setValue(bytesReceived); serverStatusLabel->setText(tr("Received %1MB") .arg(bytesReceived / (1024 * 1024))); if (bytesReceived == TotalBytes) { tcpServerConnection->close(); startButton->setEnabled(true); #ifndef QT_NO_CURSOR QApplication::restoreOverrideCursor(); #endif } } void Dialog::updateClientProgress(qint64 numBytes) { // callen when the TCP client has written some bytes bytesWritten += (int)numBytes; // only write more if not finished and when the Qt write buffer is below a certain size. if (bytesToWrite > 0 && tcpClient.bytesToWrite() <= 4*PayloadSize) bytesToWrite -= (int)tcpClient.write(QByteArray(qMin(bytesToWrite, PayloadSize), '@')); clientProgressBar->setMaximum(TotalBytes); clientProgressBar->setValue(bytesWritten); clientStatusLabel->setText(tr("Sent %1MB") .arg(bytesWritten / (1024 * 1024))); } void Dialog::displayError(QAbstractSocket::SocketError socketError) { if (socketError == QTcpSocket::RemoteHostClosedError) return; QMessageBox::information(this, tr("Network error"), tr("The following error occurred: %1.") .arg(tcpClient.errorString())); tcpClient.close(); tcpServer.close(); clientProgressBar->reset(); serverProgressBar->reset(); clientStatusLabel->setText(tr("Client ready")); serverStatusLabel->setText(tr("Server ready")); startButton->setEnabled(true); #ifndef QT_NO_CURSOR QApplication::restoreOverrideCursor(); #endif }

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