MQTT Subscriptions Example

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#include "subscriptionwindow.h" #include "ui_subscriptionwindow.h" SubscriptionWindow::SubscriptionWindow(QMqttSubscription *sub, QWidget *parent) : QWidget(parent), ui(new Ui::SubscriptionWindow), m_sub(sub) { ui->setupUi(this); ui->labelSub->setText(m_sub->topic().filter()); ui->labelQoS->setText(QString::number(m_sub->qos())); updateStatus(m_sub->state()); connect(m_sub, &QMqttSubscription::messageReceived, this, &SubscriptionWindow::updateMessage); connect(m_sub, &QMqttSubscription::stateChanged, this, &SubscriptionWindow::updateStatus); connect(m_sub, &QMqttSubscription::qosChanged, [this](quint8 qos) { ui->labelQoS->setText(QString::number(qos)); }); connect(ui->pushButton, &QAbstractButton::clicked, m_sub, &QMqttSubscription::unsubscribe); } SubscriptionWindow::~SubscriptionWindow() { m_sub->unsubscribe(); delete ui; } void SubscriptionWindow::updateMessage(const QMqttMessage &msg) { ui->listWidget->addItem(msg.payload()); } void SubscriptionWindow::updateStatus(QMqttSubscription::SubscriptionState state) { switch (state) { case QMqttSubscription::Unsubscribed: ui->labelStatus->setText(QLatin1String("Unsubscribed")); break; case QMqttSubscription::SubscriptionPending: ui->labelStatus->setText(QLatin1String("Pending")); break; case QMqttSubscription::Subscribed: ui->labelStatus->setText(QLatin1String("Subscribed")); break; case QMqttSubscription::Error: ui->labelStatus->setText(QLatin1String("Error")); break; default: ui->labelStatus->setText(QLatin1String("--Unknown--")); break; } }