Qt之UDP的网络广播例子

UDP 用户数据报协议，是一种轻量级、无连接，不可靠，数据报的传输层协议。

一般用在短消息、广播消息等中，本文中是用在广播定时发送消息中。

 

注意还是要在.pro中加入 QT += network

广播定时发送给用户数据：

1、UDP的服务器端

        先创建一个QUdpSocket对象，再创建一个定时器QTimer每秒发送一次数据，

最后利用QUdpSocket的writeDatagram()函数来设置地址和绑定端口来发送数据。

 

2、UDP的客服端

       创建一个绑定好端口的QUdpSocket对象，此时最重要的一句话

connect(udpSocket,SIGNAL(readyRead()),this,SLOT(dataReceived())); //其中dataReceived是自定义的函数，接受数据函数

当QUdpSocket对象每次要读入一个新数据的时候，就发送信号readyRead();

      再来就是编写我们自定义的接受数据函数了，利用QUdpSocket的readDatagram()函数即可获取数据。

 

截图:

 

 

 

服务端：

#ifndef UDPSERVER_H
#define UDPSERVER_H

#include 
class QLabel;
class QLineEdit;
class QUdpSocket;

class UdpServer: public QDialog
{
    Q_OBJECT

private:
    int port;
    bool isStarted;
    QUdpSocket *udpSocket;
    QTimer *timer;

    QLabel *timerLabel;
    QLineEdit *contEdit;
    QPushButton *startButton;

public:
    UdpServer(QWidget *parent = 0);

private slots:
    void slotStartButton();
    void timeoutDo();
};

#endif // UDPSERVER_H

 

#include "udpserver.h"

#include 
#include 

UdpServer::UdpServer(QWidget *parent)
    : QDialog(parent)
{
    port = 5555;
    isStarted = false;
    udpSocket = new QUdpSocket(this);
    timer = new QTimer(this);
    //设置定时器，当时间到的时候就调用timeoutDo()槽
    connect(timer, SIGNAL(timeout()), this, SLOT(timeoutDo()));

    QTextCodec::setCodecForTr(QTextCodec::codecForName("GB2312"));
    timerLabel = new QLabel(tr("定时发送"));

    contEdit = new QLineEdit;
    startButton = new QPushButton(tr("开始"));
    connect(startButton, SIGNAL(clicked()),
            this, SLOT(slotStartButton()));

    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(timerLabel);
    mainLayout->addWidget(contEdit);
    mainLayout->addWidget(startButton);
    setLayout(mainLayout);
    setWindowTitle(tr("UDP Server"));
}

void UdpServer::slotStartButton()
{
    if(false == isStarted) {
        startButton->setText(tr("停止"));
        isStarted = true;
        timer->start(1000);
    }
    else {
        startButton->setText(tr("开始"));
        isStarted = false;
        timer->stop();
    }
}

void UdpServer::timeoutDo()
{
    QString msg = contEdit->text();
    int length = 0;
    if("" == msg)
        return ;
    else if((length = udpSocket->writeDatagram(
                 msg.toLatin1(), msg.length(),
                 QHostAddress::Broadcast, port)) != msg.length()) {
        return ;
    }
}

 

#include "udpserver.h"

#include 

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    UdpServer *server = new UdpServer;
    server->show();

    return app.exec();
}

 

 

//客服端：

#ifndef UDPCLIENT_H
#define UDPCLIENT_H

#include 
class QTextEdit;
class QUdpSocket;

class UdpClient: public QDialog
{
    Q_OBJECT

private:
    int port;
    QUdpSocket *udpSocket;

    QTextEdit *showText;
    QPushButton *closeButton;

public:
    UdpClient(QWidget *parent = 0);

private slots:
    void slotClose();
    void dataReceived();
};


#endif // UDPCLIENT_H

 

#include "udpclient.h"

#include 
#include 

UdpClient::UdpClient(QWidget *parent)
    : QDialog(parent)
{
    port = 5555;
    udpSocket = new QUdpSocket(this);
    bool result = udpSocket->bind(port);
    if(!result) {
        QMessageBox::information(this, tr("error"),
                                 tr("udp socket create error!"));
        return ;
    }
    connect(udpSocket, SIGNAL(readyRead()),
            this, SLOT(dataReceived()));

    showText = new QTextEdit;
    showText->setReadOnly(true);
    closeButton = new QPushButton(tr("Close"));
    connect(closeButton, SIGNAL(clicked()),
            this, SLOT(slotClose()));

    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(showText);
    mainLayout->addWidget(closeButton);
    setLayout(mainLayout);
    setWindowTitle(tr("UDP Client"));
}

//private slots
void UdpClient::slotClose()
{
    udpSocket->close();
}

void UdpClient::dataReceived()
{
    while(udpSocket->hasPendingDatagrams()) {
        QByteArray datagram;
        datagram.resize(udpSocket->pendingDatagramSize());

        udpSocket->readDatagram(datagram.data(), datagram.size());
        showText->insertPlainText(datagram.data());
    }
}

 

#include "udpclient.h"

#include 

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    UdpClient *client = new UdpClient;
    client->show();

    return app.exec();
}