QT uses the MQTT protocol to remotely control LED lights

test Environment: mqtt_client (Publish) QT 5.6.0 win10 mqtt_client (Subscribe) Ubuntu 12.04 mqtt_broker mosquitto ubuntu 12.0.4 the QT program was developed using the QMQTT library download address Effect:

QT Client code: mainwindow.h

#ifndef mainwindow_h
#define MAINWINDOW_H

#include <QMainWindow>
#include "qmqtt.h"

Namespace Ui {
class MainWindow;
}

Class Mainwindow:public Qmainwindow
{
    q_object public

:
    explicit MainWindow (Qwidget *parent = 0);
    ~mainwindow ();

Private:
    Ui::mainwindow *ui;
    Qmqtt::client *_client;
Private slots:
    void OnConnect ();
    void OnDisconnect ();
    void Ledonslot ();
    void Ledoffslot ();
    void Adjustlightness ();
};

#endif//Mainwindow_h

Mainwindow.cpp

#include "mainwindow.h" #include "ui_mainwindow.h" #include <QString> #include <QDebug> MainWindow::
    MainWindow (Qwidget *parent): Qmainwindow (parent), UI (new Ui::mainwindow) {ui->setupui (this);
    Ui->luxhorizontalslider->setminimum (0);
    Ui->luxhorizontalslider->setmaximum (100);
    _client = new Qmqtt::client ();
    Qobject::connect (Ui->connectbtn,signal (clicked (bool)), This,slot (OnConnect ()));
    Qobject::connect (Ui->disconnectbtn,signal (clicked (bool)), This,slot (OnDisconnect ()));
    Qobject::connect (Ui->ledonbtn,signal (clicked (bool)), This,slot (Ledonslot ()));
    Qobject::connect (Ui->ledoffbtn,signal (clicked (bool)), This,slot (Ledoffslot ()));
Qobject::connect (Ui->luxhorizontalslider,signal (valuechanged (int.)), This,slot (Adjustlightness ()));

} mainwindow::~mainwindow () {Delete UI;}
    void Mainwindow::onconnect () {qhostaddress host ("127.0.0.1");
    quint16 port = 1883;
    _client->sethost (host); _client-> Setport (port);
    _client->setclientid ("Client_id_1");
    _client->setusername ("Sagarfan");
    _client->setpassword ("password");
    _client->connecttohost ();
    if (_client->isconnectedtohost ()) {Ui->statustextedit->settext ("connected"); }} void Mainwindow::ondisconnect () {if (_client->isconnectedtohost ()) {_client->disconnectfromhos
        T ();
    Ui->statustextedit->settext ("Disconnected");
    }} void Mainwindow::ledonslot () {QString payload = "{\" cmd\ ": 1}";
    Qdebug () << payload;
    Qmqtt::message msg (0, "cmd", Payload.tolatin1 ());
    if (_client->isconnectedtohost ()) {_client->publish (msg);
    } else {qdebug () << "Not Connected";
    }} void Mainwindow::ledoffslot () {QString payload ("{\" cmd\ ": 0}");
    Qdebug () << payload;
    Qmqtt::message msg (0, "cmd", Payload.tolatin1 ()); if (_client->isconnectedtohost ()) {_client->pubLish (msg);
    } else {qdebug () << "Not Connected";
    }} void Mainwindow::adjustlightness () {QString tmp = "\" lux\ ":";
    QString postfix;
    Postfix = Qstring::number (Ui->luxhorizontalslider->value ());
    Qdebug () << ui->luxhorizontalslider->value ();
    TMP + = Postfix;
    TMP + = "}";
    QString prefix ("{\" cmd\ ": 3,");

    QString payload (PREFIX+TMP);
    Qdebug () << payload;
    Qmqtt::message msg (0, "cmd", Payload.tolatin1 ());
    if (_client->isconnectedtohost ()) {_client->publish (msg);
    } else {qdebug () << "Not Connected";
 }
}

main.cpp

#include <QApplication>
#include "mainwindow.h"
#include "qmqtt.h"

int main (int argc, char *argv[])
{
    qapplication A (argc, argv);
    MainWindow W;
    W.show ();

    return a.exec ();
}