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_OBJECTQ_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();
}
)
