Simple CoAP Client Example

 // Copyright (C) 2019 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

 #include "optiondialog.h"
 #include "ui_optiondialog.h"

 OptionDialog::OptionDialog(QWidget *parent) :
     QDialog(parent),
     ui(new Ui::OptionDialog)
 {
     ui->setupUi(this);

     fillOptions();

     auto header = ui->tableWidget->horizontalHeader();
     header->setSectionResizeMode(QHeaderView::Stretch);
 }

 OptionDialog::~OptionDialog()
 {
     delete ui;
 }

 QList<QCoapOption> OptionDialog::options() const
 {
     return m_options;
 }

 void OptionDialog::on_addButton_clicked()
 {
     const auto option =
             ui->optionComboBox->currentData(Qt::UserRole).value<QCoapOption::OptionName>();
     m_options.push_back(QCoapOption(option, ui->optionValueEdit->text()));

     const auto rowCount = ui->tableWidget->rowCount();
     ui->tableWidget->insertRow(rowCount);

     QTableWidgetItem *optionItem = new QTableWidgetItem(ui->optionComboBox->currentText());
     optionItem->setFlags(optionItem->flags() ^ Qt::ItemIsEditable);
     ui->tableWidget->setItem(rowCount, 0, optionItem);

     QTableWidgetItem *valueItem = new QTableWidgetItem(ui->optionValueEdit->text());
     valueItem->setFlags(valueItem->flags() ^ Qt::ItemIsEditable);
     ui->tableWidget->setItem(rowCount, 1, valueItem);
 }

 void OptionDialog::on_clearButton_clicked()
 {
     m_options.clear();
     ui->tableWidget->setRowCount(0);
 }

 void OptionDialog::fillOptions()
 {
     ui->tableWidget->setHorizontalHeaderLabels({"Name", "Value"});
     ui->optionComboBox->addItem("None", QCoapOption::Invalid);
     ui->optionComboBox->addItem("Block1", QCoapOption::Block1);
     ui->optionComboBox->addItem("Block2", QCoapOption::Block2);
     ui->optionComboBox->addItem("Content-Format", QCoapOption::ContentFormat);
     ui->optionComboBox->addItem("If-Match", QCoapOption::IfMatch);
     ui->optionComboBox->addItem("If-None-Match", QCoapOption::IfNoneMatch);
     ui->optionComboBox->addItem("Location-Path", QCoapOption::LocationPath);
     ui->optionComboBox->addItem("Location-Query", QCoapOption::LocationQuery);
     ui->optionComboBox->addItem("Max-Age", QCoapOption::MaxAge);
     ui->optionComboBox->addItem("Observe", QCoapOption::Observe);
     ui->optionComboBox->addItem("Proxy-Scheme", QCoapOption::ProxyScheme);
     ui->optionComboBox->addItem("Proxy-Uri", QCoapOption::ProxyUri);
     ui->optionComboBox->addItem("Size1", QCoapOption::Size1);
     ui->optionComboBox->addItem("Size2", QCoapOption::Size2);
     ui->optionComboBox->addItem("Uri-Host", QCoapOption::UriHost);
     ui->optionComboBox->addItem("Uri-Path", QCoapOption::UriPath);
     ui->optionComboBox->addItem("Uri-Port", QCoapOption::UriPort);
     ui->optionComboBox->addItem("Uri-Query", QCoapOption::UriQuery);
 }