Qt 5.6 | Qt Network | Multicast Sender Example | sender.cpp Example File

Qt 5.6.3 Reference Documentation

# sender.cpp Example File

multicastsender/sender.cpp

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      #include <QtWidgets>
      #include <QtNetwork>

      #include "sender.h"

      Sender::Sender(QWidget *parent)
          : QDialog(parent)
      {
          groupAddress = QHostAddress("239.255.43.21");

          statusLabel = new QLabel(tr("Ready to multicast datagrams to group %1 on port 45454").arg(groupAddress.toString()));

          ttlLabel = new QLabel(tr("TTL for multicast datagrams:"));
          ttlSpinBox = new QSpinBox;
          ttlSpinBox->setRange(0, 255);

          QHBoxLayout *ttlLayout = new QHBoxLayout;
          ttlLayout->addWidget(ttlLabel);
          ttlLayout->addWidget(ttlSpinBox);

          startButton = new QPushButton(tr("&Start"));
          quitButton = new QPushButton(tr("&Quit"));

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

          timer = new QTimer(this);
          udpSocket = new QUdpSocket(this);
          messageNo = 1;

          connect(ttlSpinBox, SIGNAL(valueChanged(int)), this, SLOT(ttlChanged(int)));
          connect(startButton, SIGNAL(clicked()), this, SLOT(startSending()));
          connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
          connect(timer, SIGNAL(timeout()), this, SLOT(sendDatagram()));

          QVBoxLayout *mainLayout = new QVBoxLayout;
          mainLayout->addWidget(statusLabel);
          mainLayout->addLayout(ttlLayout);
          mainLayout->addWidget(buttonBox);
          setLayout(mainLayout);

          setWindowTitle(tr("Multicast Sender"));
          ttlSpinBox->setValue(1);
      }

      void Sender::ttlChanged(int newTtl)
      {
          udpSocket->setSocketOption(QAbstractSocket::MulticastTtlOption, newTtl);
      }

      void Sender::startSending()
      {
          startButton->setEnabled(false);
          timer->start(1000);
      }

      void Sender::sendDatagram()
      {
          statusLabel->setText(tr("Now sending datagram %1").arg(messageNo));
          QByteArray datagram = "Multicast message " + QByteArray::number(messageNo);
          udpSocket->writeDatagram(datagram.data(), datagram.size(),
                                   groupAddress, 45454);
          ++messageNo;
      }