Question

我想从服务器向客户端发送UDP数据包。我用C ++写的服务器/客户端代码没有问题。但是当我向QML信号发送消息时，出现的问题很少。

myudp.cpp类代码：

#include "myudp.h"
MyUDP::MyUDP(QObject *parent) : QObject(parent)
{
socket = new QUdpSocket(this);
socket->bind(QHostAddress::LocalHost, 5824);
connect(socket,SIGNAL(readyRead()),this, SLOT(readyRead()));
}

// send message in client mode
void MyUDP::SayHello()
{
    QByteArray Data;
    Data.append("test message");
    socket->writeDatagram(Data,QHostAddress::LocalHost,5824);
    // 192.168.0.100
}

void MyUDP::readyRead()
{
    QByteArray Buffer;
    Buffer.resize(socket->pendingDatagramSize());;

    QHostAddress sender;
    quint16 senderPort;

    socket->readDatagram(Buffer.data(),Buffer.size(), &sender, &senderPort);    
    qDebug()<< "Message:" << Buffer;
    setType(Buffer);
}

QByteArray MyUDP::type()
{
    return _type;
}

void MyUDP::setType(const QByteArray &t)
{
    _type = t;
    emit typeChanged();
}

myudp.h

#include <QObject>
#include <QUdpSocket>

class MyUDP : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QByteArray type READ type WRITE setType NOTIFY typeChanged)
public:
    explicit MyUDP(QObject *parent = 0);
    void SayHello();

    QByteArray type();
    void setType(const QByteArray &t);

signals:
    void typeChanged();

public slots:
    void readyRead();

private:
    QUdpSocket *socket;
    QByteArray _type;
};

为客户端和服务器端定义的myudp类。

客户端的

main.c：

#include "qtquick1applicationviewer.h"
#include <QApplication>
#include "myudp.h"

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

    QtQuick1ApplicationViewer viewer;
    viewer.addImportPath(QLatin1String("modules"));
    viewer.setOrientation(QtQuick1ApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qrc:/main.qml"));
    viewer.showExpanded();

        MyUDP client;
        client.SayHello();

    return app.exec();
}

服务器端的

main.c连接到qml：

#include "qtquick1applicationviewer.h"
#include <QApplication>
#include <QCoreApplication>
#include <QDeclarativeEngine>
#include <QDeclarativeComponent>
#include <QDebug>
#include "myudp.h"

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

    qmlRegisterType<MyUDP>("MyUDP", 1,0, "MyUDP");
    QDeclarativeEngine engine;
    QDeclarativeComponent component(&engine, QUrl("qrc:/main.qml"));
    MyUDP *myUDP = qobject_cast<MyUDP *>(component.create());    

    QtQuick1ApplicationViewer viewer;
    viewer.addImportPath(QLatin1String("modules"));
    viewer.setOrientation(QtQuick1ApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qrc:/main.qml"));
    viewer.showExpanded();

    return app.exec();
}

最后是服务器端的main.qml：

import QtQuick 1.1
import MyUDP 1.0

Rectangle {    
    width: 360
    height: 360    

    Text {
        id: txt
        text: qsTr("Hello World")
        anchors.centerIn: parent
    }

    MyUDP{
        id: myUdp
        onTypeChanged: {
            txt.text = "recived msg:" + type;
            console.log("recived massage is " + type)
        }
    }
}

我从客户端向服务器发送消息，服务器在c ++区域正确接收消息，之后我将此消息发送给QML。在QML中console.log("recived massage is " + type)正确打印消息数据，但txt.text = "recived msg:" + type;未触发，文本文件中没有显示任何内容。我很困惑为什么会这样！

套接字编程中的QML和C ++连接问题

0 个答案: