1 QT之官方MQTT的使用

https://www.cnblogs.com/chq1224/p/14962585.html

第三方库

https://blog.csdn.net/luoyayun361/article/details/104671603

2 QT之QMQTT库的安装和使用

一、下载qmqtt源码

下载地址：https://github.com/emqtt/qmqtt 二、 编译qmqtt库 三、 使用qmqtt库

四、使用示例

需要注意的是只有连接成功后才会触发发布订阅和订阅

Widget.h

  2. #ifndef WIDGET_H
  3. #define WIDGET_H
  5. #include <QWidget>
  6. #include <qmqtt.h>
  8. namespace Ui {
  9.     class Widget;
  10. }
  12. class Widget : public QWidget
  13. {
  14. Q_OBJECT
  16. public:
  17. explicit Widget(QWidget *parent = 0);
  18. ~Widget();
  20. private slots:
  22. void on_connect_clicked();
  24. void mqtt_connect_success();
  26. void mqtt_disconnect();
  28. void mqtt_sub_success(QString topic, quint8 qos = 0);
  30. void mqtt_recv_msg(QMQTT::Message msg);
  32. void on_sub_clicked();
  34. void on_pub_clicked();
  36. private:
  37. Ui::Widget *ui;
  38. QMQTT::Client *mqtt;
  39. };
  41. #endif // WIDGET_H

Widget.cpp

  1. #include "widget.h"
  2. #include "ui_widget.h"
  4. Widget::Widget(QWidget *parent) :
  5. QWidget(parent),
  6. ui(new Ui::Widget)
  7. {
  8.     ui->setupUi(this);
  9. }
  11. Widget::~Widget()
  12. {
  13.     delete ui;
  14. }
  17. void Widget::on_connect_clicked()
  18. {
  19.     mqtt = new QMQTT::Client(QHostAddress(QString(ui->host->text())),ui->port->text().toInt());
  20.     connect(mqtt, SIGNAL(connected()), this, SLOT(mqtt_connect_success()));
  21.     connect(mqtt, SIGNAL(disconnected()), this, SLOT(mqtt_disconnect()));
  22.     connect(mqtt, SIGNAL(subscribed(QString,quint8)), this, SLOT(mqtt_sub_success(QString,quint8)));
  23.     connect(mqtt, SIGNAL(received(QMQTT::Message)), this, SLOT(mqtt_recv_msg(QMQTT::Message)));
  25.     mqtt->setCleanSession(true);
  26.     mqtt->connectToHost(); //连接mqtt
  27. }
  29. void Widget::mqtt_connect_success() //连接成功
  30. {
  31.     ui->textBrowser->append("连接成功");
  32. }
  34. void Widget::mqtt_disconnect() //连接断开
  35. {
  36.     ui->textBrowser->append("连接断开");
  37. }
  39. void Widget::mqtt_sub_success(QString topic,quint8 qos) //订阅成功
  40. {
  41.     QString msg = "订阅主题 ";
  42.     msg += ui->sub_topic->text();
  43.     msg += " 成功";
  44.     ui->textBrowser->append(msg);
  45. }
  47. void Widget::mqtt_recv_msg(QMQTT::Message msg) //接收消息处理
  48. {
  49.     QString recv_msg = "Topic:";
  50.     QString data = msg.payload();
  51.     recv_msg += msg.topic();
  52.     recv_msg += "    Payload:";
  53.     recv_msg += data;
  54.     ui->textBrowser->append(recv_msg);
  55. }
  57. void Widget::on_sub_clicked() //订阅
  58. {
  59.     mqtt->subscribe(ui->sub_topic->text(),1);
  60. }
  62. void Widget::on_pub_clicked() //发布消息
  63. {
  64.     QMQTT::Message msg;
  65.     msg.setTopic(ui->pub_topic->text());
  66.     msg.setPayload(ui->pub_msg->text().toLocal8Bit());
  67.     mqtt->publish(msg);
  68. }

参考网址 已经可以确认用此方案

https://www.freesion.com/article/4264808261/