QuickSubscription example: Port CMakeLists.txt to use qt_add_qml_module

Port the CmakeLists.txt and change the source files accordingly:
- rename main.qml to Main.qml
- remove MqttClient import from Main.qml
- add QML macros to qmlmqttclient.h
- revamp main.cpp

Also update the qmake build:
- revamp quicksubscription.pro
- add qmldir to project
- remove qml.qrc

Task-number: QTBUG-110893
Change-Id: Ie7c0dd260e94c1e1ad4756fb21a70f24f2c60f87
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Oliver Eftevaag <oliver.eftevaag@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 03cc0dd51271862653fa1c8c85a093a77b5659e3)

7 files changed, 36 insertions, 39 deletions

diff --git a/examples/mqtt/quicksubscription/CMakeLists.txt b/examples/mqtt/quicksubscription/CMakeLists.txt
index 3c7c892..cbc8e77 100644
--- a/examples/mqtt/quicksubscription/CMakeLists.txt
+++ b/examples/mqtt/quicksubscription/CMakeLists.txt
@@ -4,8 +4,6 @@
 cmake_minimum_required(VERSION 3.16)
 project(quicksubscription LANGUAGES CXX)
 
-set(CMAKE_AUTOMOC ON)
-
 if(NOT DEFINED INSTALL_EXAMPLESDIR)
     set(INSTALL_EXAMPLESDIR "examples")
 endif()
@@ -14,21 +12,19 @@ set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/mqtt/quicksubscription")
 
 find_package(Qt6 REQUIRED COMPONENTS Core Gui Mqtt Qml Quick)
 
+qt_standard_project_setup(REQUIRES 6.5)
+
 qt_add_executable(quicksubscription
+    WIN32
+    MACOSX_BUNDLE
     main.cpp
-    qmlmqttclient.cpp qmlmqttclient.h
-)
-
-set_target_properties(quicksubscription PROPERTIES
-    WIN32_EXECUTABLE TRUE
-    MACOSX_BUNDLE TRUE
 )
 
 target_compile_definitions(quicksubscription PUBLIC
     QT_DEPRECATED_WARNINGS
 )
 
-target_link_libraries(quicksubscription PUBLIC
+target_link_libraries(quicksubscription PRIVATE
     Qt::Core
     Qt::Gui
     Qt::Mqtt
@@ -36,16 +32,12 @@ target_link_libraries(quicksubscription PUBLIC
     Qt::Quick
 )
 
-# Resources:
-set(qml_resource_files
-    "main.qml"
-)
-
-qt6_add_resources(quicksubscription "qml"
-    PREFIX
-        "/"
-    FILES
-        ${qml_resource_files}
+qt_add_qml_module(quicksubscription
+    URI subscription
+    QML_FILES
+        "Main.qml"
+    SOURCES
+        qmlmqttclient.cpp qmlmqttclient.h
 )
 
 install(TARGETS quicksubscription
diff --git a/examples/mqtt/quicksubscription/main.qml b/examples/mqtt/quicksubscription/Main.qml
index 7f3c48b..05f8920 100644
--- a/examples/mqtt/quicksubscription/main.qml
+++ b/examples/mqtt/quicksubscription/Main.qml
@@ -5,7 +5,6 @@ import QtQuick 2.8
 import QtQuick.Window 2.2
 import QtQuick.Controls 2.1
 import QtQuick.Layouts 1.1
-import MqttClient 1.0
 
 Window {
     visible: true
diff --git a/examples/mqtt/quicksubscription/main.cpp b/examples/mqtt/quicksubscription/main.cpp
index 785140b..b2a59d2 100644
--- a/examples/mqtt/quicksubscription/main.cpp
+++ b/examples/mqtt/quicksubscription/main.cpp
@@ -1,24 +1,21 @@
 // Copyright (C) 2017 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
-#include "qmlmqttclient.h"
+#include <QtQml/qqmlapplicationengine.h>
+#include <QtGui/qguiapplication.h>
 
-#include <QGuiApplication>
-#include <QQmlApplicationEngine>
-#include <QLoggingCategory>
+using namespace Qt::StringLiterals;
 
 int main(int argc, char *argv[])
 {
     QGuiApplication app(argc, argv);
-
     QQmlApplicationEngine engine;
 
-    qmlRegisterType<QmlMqttClient>("MqttClient", 1, 0, "MqttClient");
-    qmlRegisterUncreatableType<QmlMqttSubscription>("MqttClient", 1, 0, "MqttSubscription", QLatin1String("Subscriptions are read-only"));
+    QObject::connect(
+            &engine, &QQmlApplicationEngine::objectCreationFailed, &app,
+            []() { QCoreApplication::exit(EXIT_FAILURE); }, Qt::QueuedConnection);
 
-    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
-    if (engine.rootObjects().isEmpty())
-        return -1;
+    engine.loadFromModule(u"subscription"_s, u"Main"_s);
 
-    return app.exec();
+    return QGuiApplication::exec();
 }
diff --git a/examples/mqtt/quicksubscription/qml.qrc b/examples/mqtt/quicksubscription/qml.qrc
deleted file mode 100644
index 5f6483a..0000000
--- a/examples/mqtt/quicksubscription/qml.qrc
+++ /dev/null
@@ -1,5 +0,0 @@
-<RCC>
-    <qresource prefix="/">
-        <file>main.qml</file>
-    </qresource>
-</RCC>
diff --git a/examples/mqtt/quicksubscription/qmldir b/examples/mqtt/quicksubscription/qmldir
new file mode 100644
index 0000000..fa16d60
--- /dev/null
+++ b/examples/mqtt/quicksubscription/qmldir
@@ -0,0 +1,4 @@
+module subscription
+
+prefer :/qt/qml/subscription/
+Main 1.0 Main.qml
diff --git a/examples/mqtt/quicksubscription/qmlmqttclient.h b/examples/mqtt/quicksubscription/qmlmqttclient.h
index e229288..05a86c4 100644
--- a/examples/mqtt/quicksubscription/qmlmqttclient.h
+++ b/examples/mqtt/quicksubscription/qmlmqttclient.h
@@ -8,12 +8,15 @@
 #include <QtMqtt/QMqttClient>
 #include <QtMqtt/QMqttSubscription>
 
+#include <QtQml/qqml.h>
+
 class QmlMqttClient;
 
 class QmlMqttSubscription : public QObject
 {
     Q_OBJECT
     Q_PROPERTY(QMqttTopicFilter topic MEMBER m_topic NOTIFY topicChanged)
+    QML_UNCREATABLE("Not intended to be creatable")
 public:
     QmlMqttSubscription(QMqttSubscription *s, QmlMqttClient *c);
     ~QmlMqttSubscription();
@@ -38,6 +41,7 @@ class QmlMqttClient : public QObject
     Q_PROPERTY(QString hostname READ hostname WRITE setHostname NOTIFY hostnameChanged)
     Q_PROPERTY(int port READ port WRITE setPort NOTIFY portChanged)
     Q_PROPERTY(QMqttClient::ClientState state READ state WRITE setState NOTIFY stateChanged)
+    QML_NAMED_ELEMENT(MqttClient)
 public:
 
     QmlMqttClient(QObject *parent = nullptr);
diff --git a/examples/mqtt/quicksubscription/quicksubscription.pro b/examples/mqtt/quicksubscription/quicksubscription.pro
index 474fb39..0b32bfd 100644
--- a/examples/mqtt/quicksubscription/quicksubscription.pro
+++ b/examples/mqtt/quicksubscription/quicksubscription.pro
@@ -1,7 +1,8 @@
 TEMPLATE = app
+TARGET = quicksubscription
 
 QT += qml quick mqtt
-CONFIG += c++11
+CONFIG += qmltypes
 
 SOURCES += main.cpp \
     qmlmqttclient.cpp
@@ -9,10 +10,15 @@ SOURCES += main.cpp \
 HEADERS += \
     qmlmqttclient.h
 
-RESOURCES += qml.qrc
+qml_resources.files = Main.qml qmldir
+qml_resources.prefix = /qt/qml/subscription
+
+RESOURCES += qml_resources
 
 # Additional import path used to resolve QML modules in Qt Creator's code model
-QML_IMPORT_PATH =
+QML_IMPORT_PATH = $$pwd/.
+QML_IMPORT_NAME = subscription
+QML_IMPORT_MAJOR_VERSION = 1
 
 # Additional import path used to resolve QML modules just for Qt Quick Designer
 QML_DESIGNER_IMPORT_PATH =