Qt udp multicast Qt udp multicast

 code part:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QLabel>
#include <QUdpSocket>
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
private slots:
    void onSocketStateChange(QAbstractSocket::SocketState socketState);
    void onSocketReadyRead();//Read the incoming data from the socket

    void on_bindBtn_clicked();

    void on_stopBtn_clicked();

    void on_btnSend_clicked();

    void on_clearBtn_clicked();

    void on_quitBtn_clicked();

private:
    QLabel* LabSocketState;//socket status display label
    QUdpSocket* udpSocket;
    QString getLocalIp();//Get local IP address
    QHostAddress groupAddress;//multicast address

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QHostInfo>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{     ui->setupUi(this) ;     LabSocketState = new QLabel("Socket State");     LabSocketState->setMinimumWidth(200);     ui->statusBar->addWidget(LabSocketState);     QString localIP = getLocalIp();//Get IP address     this->setWindowTitle(this- >windowTitle()+"---local IP"+localIP);     udpSocket = new QUdpSocket;     udpSocket->setSocketOption(QAbstractSocket::MulticastTtlOption,1);//Set parameters for socket








    connect(udpSocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),this,SLOT(onSocketStateChange(QAbstractSocket::SocketState)));
    onSocketStateChange(udpSocket->state());
    connect(udpSocket,SIGNAL(readyRead()),this,SLOT(onSocketReadyRead()));

}
void MainWindow::on_bindBtn_clicked()
{//join multicast
    QString IP = ui->comboTargetIp->currentText();
    groupAddress = QHostAddress(IP);
    quint16 groupPort = ui->spinBox->value();//port
    if(udpSocket->bind(QHostAddress::AnyIPv4,groupPort,QUdpSocket::ShareAddress))
    {         udpSocket->joinMulticastGroup(groupAddress);//Join multicast group         ui->plainTextEdit->appendPlainText("**Join multicast successfully ");         ui->plainTextEdit->appendPlainText("Multicast address IP: "+IP);         ui->plainTextEdit->appendPlainText("**Binding port: "+QString::number(groupPort));         ui- >bindBtn->setEnabled(false);         ui->stopBtn->setEnabled(true);         ui->comboTargetIp->setEnabled(true);







    }
    else
    {         ui->plainTextEdit->appendPlainText("**Port binding failed");     }

}

void MainWindow::on_stopBtn_clicked()
{//Exit multicast
    udpSocket->leaveMulticastGroup(groupAddress);//Exit multicast
    udpSocket->abort();
    ui->bindBtn->setEnabled(true);
    ui->stopBtn-> setEnabled(false);
    ui->comboTargetIp->setEnabled(true);
    ui->plainTextEdit->appendPlainText("** has quit multicast, unbind the port");
}

void MainWindow::on_btnSend_clicked()
{//发送组播消息
    quint16 groupPort = ui->spinBox->value();
    QString msg = ui->lineEdit->text();
    QByteArray array;
    array = msg.toUtf8();
    udpSocket->writeDatagram(array,groupAddress,groupPort);
    ui->plainTextEdit->appendPlainText("[multicst]"+msg);
    ui->lineEdit->clear();
    ui->lineEdit->setFocus();
}

void MainWindow::on_clearBtn_clicked()
{
    ui->plainTextEdit->clear();
}

void MainWindow::on_quitBtn_clicked()
{     this->close(); } void MainWindow::onSocketReadyRead() {//Read datagram     QByteArray datagram;     datagram.resize(udpSocket->pendingDatagramSize());     QHostAddress peerAddr;     quint16 peerPort ;     udpSocket->readDatagram(datagram.data(),datagram.size(),&peerAddr,&peerPort);     QString str =datagram.data();     QString peerStr = "[From"+peerAddr.toString()+":"+ QString::number(peerPort)+"]";     ui->plainTextEdit->appendPlainText(peerStr); } QString MainWindow::getLocalIp() {//Get local IP     QString hostName = QHostInfo::localHostName();// local hostname
















    QHostInfo hostInfo = QHostInfo::fromName(hostName);
    QString localIP = " ";
    QList<QHostAddress> addList = hostInfo.addresses();
    if(!addList.isEmpty())
    {
        for(int i=0;i<addList.count();++i)
        {
            QHostAddress aHost = addList.at(i);
            if(QAbstractSocket::IPv4Protocol == aHost.protocol())
            {
                localIP = aHost.toString();
                break;
            }
        }
    }
    return localIP;
}
void MainWindow::onSocketStateChange(QAbstractSocket::SocketState socketState)
{//socket状态变化
    switch(socketState)
    {
    case QAbstractSocket::UnconnectedState:
    {
        LabSocketState->setText("socket状态：UnconnectedState");
        break;
    }
    case QAbstractSocket::HostLookupState:
    {
        LabSocketState->setText("socket状态：HostLookupState");
        break;
    }
    case QAbstractSocket::ConnectingState:
    {
        LabSocketState->setText("socket状态：ConnectingState");
        break;
    }
    case QAbstractSocket::ConnectedState:
    {
        LabSocketState->setText("socket状态：ConnectedState");
        break;
    }
    case QAbstractSocket::BoundState:
    {
        LabSocketState->setText("socket状态：BoundState");
        break;
    }
    case QAbstractSocket::ClosingState:
    {
        LabSocketState->setText("socket状态：ClosingState");
        break;
    }
    case QAbstractSocket::ListeningState:
    {
        LabSocketState->setText("socket状态：ListeningState");
        break;
    }
    }

}
MainWindow::~MainWindow()
{
    delete ui;
    udpSocket = NULL;
    delete udpSocket;
}