add service object that spins new event loop with message box

CMakeLists.txt

@@ -11,10 +11,12 @@ set(CMAKE_AUTORCC ON)
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-find_package(QT NAMES Qt6 Qt5 COMPONENTS Core Quick REQUIRED)
-find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Core Quick REQUIRED)
+find_package(QT NAMES Qt6 Qt5 COMPONENTS Core Quick Widgets REQUIRED)
+find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Core Quick Widgets REQUIRED)
 
 add_executable(quick-nested-event-loop
+  helloservice.cpp
+  helloservice.h
   main.cpp
   qml.qrc
 )
@@ -22,4 +24,7 @@ add_executable(quick-nested-event-loop
 target_compile_definitions(quick-nested-event-loop
   PRIVATE $<$<OR:$<CONFIG:Debug>,$<CONFIG:RelWithDebInfo>>:QT_QML_DEBUG>)
 target_link_libraries(quick-nested-event-loop
-  PRIVATE Qt${QT_VERSION_MAJOR}::Core Qt${QT_VERSION_MAJOR}::Quick)
+  PRIVATE
+  Qt${QT_VERSION_MAJOR}::Core
+  Qt${QT_VERSION_MAJOR}::Quick
+  Qt${QT_VERSION_MAJOR}::Widgets)

helloservice.cpp

+#include <QMessageBox>
+#include "helloservice.h"
+
+HelloService::HelloService(QObject *parent) : QObject(parent)
+{
+}
+
+void HelloService::greeting() const
+{
+    QMessageBox dlg(QMessageBox::NoIcon, tr("Hello world!"), tr("Hello world!"));
+    dlg.exec();
+}

helloservice.h

+#ifndef HELLOSERVICE_H
+#define HELLOSERVICE_H
+
+#include <QObject>
+#include <QString>
+
+class HelloService : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit HelloService(QObject *parent = nullptr);
+
+    Q_INVOKABLE void greeting() const;
+};
+
+#endif // HELLOSERVICE_H

main.cpp

-#include <QGuiApplication>
+#include <QApplication>
 #include <QQmlApplicationEngine>
+#include <QQmlContext>
+#include <QVariant>
+#include <QVector>
+#include "helloservice.h"
 
 int main(int argc, char *argv[])
 {
     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 
-    QGuiApplication app(argc, argv);
+    QApplication app(argc, argv);
 
+    HelloService service;
     QQmlApplicationEngine engine;
+    auto *context = engine.rootContext();
+    context->setContextProperties({
+        {QStringLiteral("serviceObject"), QVariant::fromValue(&service)},
+    });
+
     const QUrl url(QStringLiteral("qrc:/main.qml"));
     QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                      &app, [url](QObject *obj, const QUrl &objUrl) {