QML with C ++ objects

A, defines the subclass QObject

Myudp.h

#ifndef MYUDP_H
#define MYUDP_H

#include <QObject>
#include <QUdpSocket>
class Myudp : public QObject
{
    Q_OBJECT
public:
    explicit Myudp(QObject *parent = nullptr);
signals:
    void rcvdDataSignal(const QByteArray&);
    void sendedSignal(const QString&);//发送成功
public slots:
    void initUdpSlot();
    void requestSlot();
    void sendSlot(const QByteArray&);
private:
    QUdpSocket* udpClient = nullptr;
    const QString localIp="127.0.0.1";
    const quint16 localPort=8080;
    const QString aimIp="127.0.0.1";
    const quint16 aimPort=8888;
};

#endif // MYUDP_H

Myudp.cpp

#include " myudp.h " 

MyUDP :: MyUDP (QObject * parent): QObject (parent) 
{ 

} 

/ * ************************************************************ ************************************************************ * / 
// Z function name: initializes
 // H function operates: NULL
 // U arguments: NULL
 // X function return value: NULL
 // the y-Note: NULL 
/ * ***************************************** **** * / 
void MyUDP :: initUdpSlot () 
{ 
    IF (UdpClient == nullptr a) 
    { 
        UdpClient = new new on QUdpSocket ( the this );
        UdpClient -> the bind (QHostAddress (LocalIP), localPort is); 
        QObject :: Connect (UdpClient, the SIGNAL (the readyRead ()), the this , the SLOT (requestSlot ())); 
    } 
} 

/ * *************************************** ************************************ * / 
// Z function name: receiving data
 // H function action: NULL
 // U arguments: NULL
 // X function returns the value: NULL
 // Y NOTE: NULL 
/ * ************************************************************ ************************************************************ * / 
void MyUDP :: requestSlot () 
{ 
    IF (udpClient-> pendingDatagramSize () == 0 ) 
    { 
        return ; 
    } 
    the QByteArray BA;
    ba.resize (UdpClient -> pendingDatagramSize ()); 
    QHostAddress tempHost ( "" ); 
    quint16 Port = 0 ; 
    UdpClient -> readDatagram (ba.data (), udpClient-> pendingDatagramSize (), & tempHost, & Port); 

    EMIT rcvdDataSignal (BA); 
} 

/ * * 
 * function name: transmitting slot function 
 * function parameter: NULL 
 * function operates: NULL 
 * function return value: NULL 
 * Note: NULL 
 * / 
void MyUDP :: sendSlot ( const the QByteArray & info) 
{ 
    IF (info.size () == udpClient->  writeDatagram (info, QHostAddress (aimIp), aimPort))
    { 
        QString STR = info.toHex().toUpper();
        emit sendedSignal(str);
    }
}

Second, the registration Myudp class, instantiated in QML [Embodiment 1]

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QThread>
#include "myudp.h"
#include <QQuickView>
#include <QQmlContext>
int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);

    qmlRegisterType<Myudp>("Myudp.module",1,0,"Myudp");
    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

main.qml

import QtQuick 2.9
import QtQuick.Window 2.2
import Myudp.module 1.0
import QtQuick.Controls 2.2
Window {
    id: root
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Myudp{
        id:udp
    }
    Row{
        Button {
            id: connetBtn
            text: qsTr("连接")
            onClicked: {
                udp.initUdpSlot()
            }
        }

        Button {
            id: sendBtn
            text: qsTr("发送")
            onClicked: {
                udp.sendSlot("123")
            }
        }
    }
}

Third, the registration Myudp objects directly in QML

 main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QThread>
#include "myudp.h"
#include <QQuickView>
#include <QQmlContext>
int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);


    Myudp udp;

    QQmlApplicationEngine engine;
    engine.rootContext()->setContextProperty("udp",&udp);//注册对象
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

main.qml

import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Controls 2.2
Window {
    id: root
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Row{
        Button {
            id: connetBtn
            text: qsTr("连接")
            onClicked: {
                udp.initUdpSlot()
            }
        }

        Button {
            id: sendBtn
            text: qsTr("发送")
            onClicked: {
                udp.sendSlot("123")
            }
        }
    }
}