Qt 中集成mqtt協(xié)議的使用方法

更新時間：2025年02月24日 12:04:13 作者：土撥鼠不是老鼠

文章介紹了如何在工程中引入qmqtt庫,并通過聲明一個單例類來暴露訂閱到的主題數據,本文通過實例代碼給大家介紹的非常詳細,感興趣的朋友一起看看吧

一，引入qmqtt 庫

我是將整個頭文件/源文件都添加到了工程中進行編譯，這樣跨平臺時方便，直接編譯就行了。

原始倉庫路徑：https://github.com/emqx/qmqtt/tree/master

二，使用

聲明一個單例類，將訂閱到主題，直接以屬性的方式進行暴露，這樣QML文件中就可以直接使用。下邊是訂閱一個溫度和濕度的主題數據。

#ifndef MQTTMANAGERT_H
#define MQTTMANAGERT_H
#include <iostream>
#include <mqtt/qmqtt.h>
class MQTTManager:public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString inTemperature READ getInTemperature WRITE setInTemperature NOTIFY inTemperatureChanged FINAL)
    Q_PROPERTY(QString inHumidity READ getInHumidity WRITE setInHumidity NOTIFY inHumidityChanged FINAL)
public:
    static MQTTManager* instance();
    QString getInTemperature() const;
    void setInTemperature(QString newInTemperature);
    QString getInHumidity() const;
    void setInHumidity(QString newInHumidity);
private:
    ~MQTTManager();
    MQTTManager();
public slots:
    void doConnected();
    void onSubscribed(const QString& topic);
    void doDisconnected();
    void doDataReceived(QMQTT::Message message);
signals:
    void inTemperatureChanged();
    void inHumidityChanged();
private:
    QMQTT::Client *client;
    static MQTTManager *manager;
    QString inTemperature;
    QString inHumidity;
};
#endif // MQTTMANAGERT_H

#include "mqttManagert.h"
MQTTManager* MQTTManager::manager=nullptr;
const QString HOST= "127.0.0.1"; //服務器地址
//需要訂閱的主題
const QString TOPIC_IN_TEMPERATURE_HUMIDITY ="qmqtt/in_temperature_humidity";
MQTTManager::MQTTManager(){
    client = new QMQTT::Client(QHostAddress(HOST),1883,this);
    connect(client,&QMQTT::Client::connected,this,&MQTTManager::doConnected);
    connect(client,&QMQTT::Client::disconnected,this,&MQTTManager::doDisconnected);
    connect(client,&QMQTT::Client::received,this,&MQTTManager::doDataReceived);
    connect(client, &QMQTT::Client::subscribed, this, &MQTTManager::onSubscribed);
    client->connectToHost();
}
MQTTManager::~MQTTManager(){
    client->disconnected();
}
MQTTManager* MQTTManager::instance(){
    if(!manager){
        manager = new MQTTManager();
    }
    return manager;
}
void MQTTManager::doConnected(){
    qDebug()<<"doConnected ok";
    //再此訂閱主題
    client->subscribe(TOPIC_IN_TEMPERATURE_HUMIDITY);
}
void MQTTManager::onSubscribed(const QString& topic)
{
    qDebug() << "onSubscribed " << topic;
}
void MQTTManager::doDataReceived(QMQTT::Message message){
    //收到消息
    QString mes = QString(message.id())+" "+QString(message.qos())+" "+message.topic()+" "+message.payload()+"\n";
    qDebug()<<"dataReceived "<<mes;
   //根據主題過濾消息
    if(message.topic()==TOPIC_IN_TEMPERATURE_HUMIDITY){
        QStringList dataList = QString(message.payload()).split(",");
        if(dataList.size()==2){
            setInTemperature(dataList[0]);
            setInHumidity(dataList[1]);
        }
    }
}
void MQTTManager::doDisconnected(){
    qDebug()<<"doDisconnected ok";
}
QString MQTTManager::getInTemperature() const
{
    return inTemperature;
}
void MQTTManager::setInTemperature(QString newInTemperature)
{
    if (inTemperature == newInTemperature)
        return;
    inTemperature = newInTemperature;
    emit inTemperatureChanged();
}
QString MQTTManager::getInHumidity() const
{
    return inHumidity;
}
void MQTTManager::setInHumidity(QString newInHumidity)
{
    if (inHumidity == newInHumidity)
        return;
    inHumidity = newInHumidity;
    emit inHumidityChanged();
}

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