Qt dialog example

CMakeLists.txt

cmake_minimum_required(VERSION 3.5)

project(diagtest VERSION 0.1 LANGUAGES CXX)

set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Widgets)
find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Widgets)

qt_add_executable(diagtest
    MANUAL_FINALIZATION
    main.cpp
)
target_link_libraries(diagtest PRIVATE Qt${QT_VERSION_MAJOR}::Widgets)

# https://doc.qt.io/qt-6/wasm.html#asyncify
target_link_options(diagtest PUBLIC -sASYNCIFY -Os)

if(QT_VERSION_MAJOR EQUAL 6)
    qt_finalize_executable(diagtest)
endif()

main.cpp

#include <QApplication>
#include <QDialog>
#include <QLabel>
#include <QMessageBox>
#include <QPushButton>
#include <QVBoxLayout>

#include <iostream>


int main(int argc, char *argv[]) {
  QApplication a(argc, argv);
  QMainWindow w;
  auto button = new QPushButton("Click me");
  auto label = new QLabel("Result");
  auto layout = new QVBoxLayout;
  layout->addWidget(button);
  layout->addWidget(label);
  auto *widget = new QWidget;
  widget->setLayout(layout);
  w.setCentralWidget(widget);

  auto *wptr = &w;
  button->connect(button, &QPushButton::clicked, label, [=]() {
    auto res = QMessageBox::question(wptr, "Question", "press yes or no");
    std::cout << "Hello!" << res << std::endl;
    // A new message box which shows the value of the result
    QMessageBox::information(wptr, "Result", QString::number(res));

    label->setText(QString::number(res));
  });

  w.showMaximized();
  return a.exec();
}