這篇博文的例子是說(shuō)明如何在局域網(wǎng)上搭建廣播包接收端。

這里使用了Qt Network API，搭建本地廣播包接收端。

結(jié)構(gòu)如下：

代碼如下：

receiver.h

#ifndef RECEIVER_H #define RECEIVER_H#include <QWidget>QT_BEGIN_NAMESPACE class QLabel; class QUdpSocket; QT_END_NAMESPACEclass Receiver : public QWidget {Q_OBJECTpublic:explicit Receiver(QWidget *parent = nullptr);private slots:void processPendingDatagrams();private:QLabel *statusLabel = nullptr;QUdpSocket *udpSocket = nullptr; };#endif

?main.cpp

#include <QApplication>#include "receiver.h"int main(int argc, char *argv[]) {QApplication app(argc, argv);Receiver receiver;receiver.show();return app.exec(); }

?receiver.cpp

#include <QtWidgets> #include <QtNetwork>#include "receiver.h"Receiver::Receiver(QWidget *parent): QWidget(parent) {statusLabel = new QLabel(tr("Listening for broadcasted messages"));statusLabel->setWordWrap(true);auto quitButton = new QPushButton(tr("&Quit"));//! [0]udpSocket = new QUdpSocket(this);udpSocket->bind(45454, QUdpSocket::ShareAddress); //! [0]//! [1]connect(udpSocket, SIGNAL(readyRead()),this, SLOT(processPendingDatagrams())); //! [1]connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));auto buttonLayout = new QHBoxLayout;buttonLayout->addStretch(1);buttonLayout->addWidget(quitButton);buttonLayout->addStretch(1);auto mainLayout = new QVBoxLayout;mainLayout->addWidget(statusLabel);mainLayout->addLayout(buttonLayout);setLayout(mainLayout);setWindowTitle(tr("Broadcast Receiver")); }void Receiver::processPendingDatagrams() {QByteArray datagram; //! [2]while (udpSocket->hasPendingDatagrams()) {datagram.resize(int(udpSocket->pendingDatagramSize()));udpSocket->readDatagram(datagram.data(), datagram.size());statusLabel->setText(tr("Received datagram: \"%1\"").arg(datagram.constData()));} //! [2] }

解釋關(guān)鍵代碼：

解釋：廣播報(bào)使用的是UDP，所以用的是QUdpSocket，并且綁定了端口45454。

?

解釋：關(guān)聯(lián)了信號(hào)與槽當(dāng)網(wǎng)卡緩存中有數(shù)據(jù)時(shí)，調(diào)用對(duì)應(yīng)的槽函數(shù)進(jìn)行讀取。

?解釋：當(dāng)緩存區(qū)有數(shù)據(jù)時(shí)：hasPendingDatagrams()，然后就使用QByteArray獲取讀到的數(shù)據(jù)，最后設(shè)置到label上。

?

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