Qt中简单使用MQTT(一)

Qt中简单使用MQTT(一)MQTT简介可以看下这篇文章MQTT简介一、MQTT库配置1.下载MQTT源码我们的QtCreator中是不带MQTT模块的需要我们自己去下载。使用git工具下载如下由于我用的是 Qt6.6.0 版本下载是需要严格对应 6.6.0版本。git clone https://github.com/qt/qtmqtt.git cd qtmqtt git checkout 6.6.0下载完后文件如图2.编译MQTT源码1.步骤使用QtCreator打开上述的CMakeList.txt文件并且选择构建套件。如图我的构建套件中只能选择MingGW 64bit和MSVC 2019 64Bit,我这里选择生成的是MingGW 64位。2.选择release版本生成.a和.dll文件如下所示3.将库复制到QtCreator配置中需要复制的文件清单源文件你 build 目录里的目标位置Qt 6.6.0 目录build\...\include\下的所有头文件E:\QtCreator\QtCreator\6.6.0\mingw_64\include\QtMqtt\build\...\lib\libQt6Mqtt.aE:\QtCreator\QtCreator\6.6.0\mingw_64\lib\build\...\lib\Qt6Mqtt.prlE:\QtCreator\QtCreator\6.6.0\mingw_64\lib\build\...\lib\cmake\Qt6Mqtt\下所有文件E:\QtCreator\QtCreator\6.6.0\mingw_64\lib\cmake\Qt6Mqtt\build\...\bin\Qt6Mqtt.dllE:\QtCreator\QtCreator\6.6.0\mingw_64\bin\头文件在源码目录qtmqtt\src\mqtt\下.h 文件需要全部复制过去。如下图,是我已经复制完成后的目录二、在项目中使用MQTT库1.加载MQTT库创建一个QWidget 的MQTTTest项目并且在CMakeList.txt文件中加载MQTT库,如下图2.项目测试代码如下MainWindow.h#ifndef MAINWINDOW_H #define MAINWINDOW_H #include QMainWindow #include QMqttClient QT_BEGIN_NAMESPACE class QLineEdit; class QPushButton; class QTextEdit; class QVBoxLayout; QT_END_NAMESPACE QT_BEGIN_NAMESPACE namespace Ui { class MainWindow; } QT_END_NAMESPACE class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent nullptr); ~MainWindow(); private: Ui::MainWindow *ui; private slots: void onConnectClicked(); void onSubscribeClicked(); void onPublishClicked(); void onConnected(); void onMessageReceived(const QByteArray message, const QMqttTopicName topic); void onDisconnected(); void onErrorChanged(QMqttClient::ClientError error); private: QMqttClient *m_client; // UI QLineEdit *m_hostEdit; QLineEdit *m_portEdit; QLineEdit *m_topicEdit; QLineEdit *m_msgEdit; QPushButton *m_connectBtn; QPushButton *m_subBtn; QPushButton *m_pubBtn; QTextEdit *m_logEdit; }; #endif // MAINWINDOW_HMainWindow.cpp#include mainwindow.h #include QLineEdit #include QPushButton #include QTextEdit #include QVBoxLayout #include QHBoxLayout #include QWidget #include QDebug MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) , m_client(new QMqttClient(this)) { // 中心窗口 auto *central new QWidget(this); auto *mainLayout new QVBoxLayout(central); // 连接区域 auto *connLayout new QHBoxLayout(); m_hostEdit new QLineEdit(broker.hivemq.com, this); m_portEdit new QLineEdit(1883, this); m_connectBtn new QPushButton(连接, this); connLayout-addWidget(m_hostEdit); connLayout-addWidget(m_portEdit); connLayout-addWidget(m_connectBtn); // 订阅区域 auto *subLayout new QHBoxLayout(); m_topicEdit new QLineEdit(test/topic, this); m_subBtn new QPushButton(订阅, this); subLayout-addWidget(m_topicEdit); subLayout-addWidget(m_subBtn); // 发布区域 auto *pubLayout new QHBoxLayout(); m_msgEdit new QLineEdit(Hello MQTT, this); m_pubBtn new QPushButton(发布, this); pubLayout-addWidget(m_msgEdit); pubLayout-addWidget(m_pubBtn); // 日志显示 m_logEdit new QTextEdit(this); m_logEdit-setReadOnly(true); mainLayout-addLayout(connLayout); mainLayout-addLayout(subLayout); mainLayout-addLayout(pubLayout); mainLayout-addWidget(m_logEdit); setCentralWidget(central); setWindowTitle(Qt MQTT Demo); resize(500, 400); // 信号连接 connect(m_connectBtn, QPushButton::clicked, this, MainWindow::onConnectClicked); connect(m_subBtn, QPushButton::clicked, this, MainWindow::onSubscribeClicked); connect(m_pubBtn, QPushButton::clicked, this, MainWindow::onPublishClicked); connect(m_client, QMqttClient::connected, this, MainWindow::onConnected); connect(m_client, QMqttClient::messageReceived, this, MainWindow::onMessageReceived); connect(m_client, QMqttClient::disconnected, this, MainWindow::onDisconnected); connect(m_client, QMqttClient::errorChanged, this, MainWindow::onErrorChanged); } MainWindow::~MainWindow() default; void MainWindow::onConnectClicked() { m_client-setHostname(m_hostEdit-text()); m_client-setPort(m_portEdit-text().toInt()); m_client-connectToHost(); m_logEdit-append(正在连接...); } void MainWindow::onSubscribeClicked() { auto sub m_client-subscribe(m_topicEdit-text()); if (sub) { m_logEdit-append(已订阅: m_topicEdit-text()); } else { m_logEdit-append(订阅失败请检查是否已连接); } } void MainWindow::onPublishClicked() { auto result m_client-publish(m_topicEdit-text(), m_msgEdit-text().toUtf8()); if (result -1) { m_logEdit-append(发布失败); } else { m_logEdit-append(已发送: m_msgEdit-text()); } } void MainWindow::onConnected() { m_logEdit-append(✅ MQTT 连接成功!); m_connectBtn-setText(已连接); m_connectBtn-setEnabled(false); } void MainWindow::onMessageReceived(const QByteArray message, const QMqttTopicName topic) { m_logEdit-append( [ topic.name() ] QString(message)); } void MainWindow::onDisconnected() { m_logEdit-append(❌ 连接断开); m_connectBtn-setText(连接); m_connectBtn-setEnabled(true); } void MainWindow::onErrorChanged(QMqttClient::ClientError error) { m_logEdit-append(⚠️ 错误: QString::number(error)); }项目运行效果好了关于MOTT的使用就介绍到这里了。