QTcpSocket example

1 include header file

> #include <QTcpSocket>

  #include <qabstractsocket.h>

2. declare a variable

QTcpSocket *tcpClient = Q_NULLPTR;

3 connect slot

connect(tcpClient, SIGNAL(connected()), this, SLOT(connectedToDM()));//check connected server

connect(tcpClient, SIGNAL(readyRead()), this, SLOT(ReceiveServerData())); //receive data from server

connect(tcpClient, SIGNAL(disconnected()), this, SLOT(disconnectedfromDM())); //receive signal when disconnected

connect(tcpClient, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError)));//// check socket error from server

4. try to connect to server

tcpClient->connectToHost(m_dm_ip, 8000);

5. try to disconnect from server

tcpClient->disconnectFromHost();

6. send message to server

qint64 result = tcpClient->write(data.constData());

7. receive data from server

void MainWindow::ReceiveServerData()

{   

QByteArray servermsg = tcpClient->readAll();    

    QString msg = QString::fromUtf8(servermsg.constData());

 }

8. control socket error

void MainWindow::displayError(QAbstractSocket::SocketError socketError)

{

    Log();

    if (socketError == QTcpSocket::RemoteHostClosedError)

        return;