qtquick: Introduce QML singletons

This will make QML tooling happier.

examples/qtquick/customtabbar/MyTabBar.qml

@@ -53,7 +53,7 @@ KDDW.TabBarBase {
                 onPressed: {
                     /// Do not use random uuids if you're planing to use layout save/restore!
                     /// Using them here for convenience of the exercise
-                    var uniqueName = _kddwHelpers.generateUuid();
+                    var uniqueName = Singletons.helpers.generateUuid();
 
                     var code = `import com.kdab.dockwidgets 2.0 as KDDW;
                                 import QtQuick 2.6;

examples/qtquick/dockwidgets/main.qml

@@ -62,7 +62,7 @@ ApplicationWindow {
                 onTriggered: {
                     /// Do not use random uuids if you're planing to use layout save/restore!
                     /// Using them here for convenience of the exercise
-                    var uniqueName = _kddwHelpers.generateUuid();
+                    var uniqueName = KDDW.Singletons.helpers.generateUuid();
 
                     var code = `import com.kdab.dockwidgets 2.0 as KDDW;
                                 import QtQuick 2.6;

src/CMakeLists.txt

@@ -531,6 +531,13 @@ if(KDDW_FRONTEND_QTQUICK)
     set(QT_QML_GENERATE_QMLLS_INI ON)
 
     set(KDDW_MODULE_QML_ELEMENTS
+        qtquick/Singletons.cpp
+        qtquick/Singletons_p.h
+        qtquick/Helpers.cpp
+        qtquick/Helpers_p.h
+        qtquick/ViewFactory.cpp
+        qtquick/ViewFactory.h
+        core/ViewFactory.h
         qtquick/MainWindowInstantiator.cpp
         qtquick/MainWindowInstantiator.h
         qtquick/LayoutSaverInstantiator.cpp

src/core/DockRegistry.h

@@ -47,7 +47,8 @@ class MainWindowMDI;
 class DOCKS_EXPORT DockRegistry : public Core::Object, public Core::EventFilterInterface
 {
     Q_OBJECT
-
+    QML_ELEMENT
+    QML_UNCREATABLE("Created by the framework only.")
 public:
     enum class DockByNameFlag {
         None = 0,
@@ -61,7 +62,7 @@ class DOCKS_EXPORT DockRegistry : public Core::Object, public Core::EventFilterI
     static DockRegistry *self();
     static bool isInitialized();
 
-    ~DockRegistry();
+    ~DockRegistry() override;
     void registerDockWidget(Core::DockWidget *);
     void unregisterDockWidget(Core::DockWidget *);
 

src/core/ViewFactory.h

@@ -56,6 +56,8 @@ class TitleBar;
 class DOCKS_EXPORT ViewFactory : public Core::Object
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("Created by the framework only.")
 public:
     ViewFactory() = default;
 

src/qtquick/Helpers_p.h

@@ -12,7 +12,7 @@
 #ifndef KD_QTQUICK_HELPERS_P_H
 #define KD_QTQUICK_HELPERS_P_H
 
-#include <QObject>
+#include <QQmlEngine>
 
 #include <kdbindings/signal.h>
 
@@ -26,6 +26,8 @@ namespace KDDockWidgets {
 class QtQuickHelpers : public QObject
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("Created by the framework only.")
     Q_PROPERTY(
         QObject *groupViewInMDIResize READ groupViewInMDIResize NOTIFY groupInMDIResizeChanged)
 

src/qtquick/Platform.cpp

@@ -266,3 +266,8 @@ Core::DockWidget *Platform::dockWidgetForItem(QQuickItem *item)
 
     return nullptr;
 }
+
+QtQuickHelpers *Platform::helpers() const
+{
+    return m_qquickHelpers;
+}

src/qtquick/Platform.h

@@ -56,6 +56,8 @@ class DOCKS_EXPORT Platform : public QtCommon::Platform_qt
     void ungrabMouse() override;
     void onViewFactoryChanged() override;
 
+    QtQuickHelpers *helpers() const;
+
     static Platform *instance();
 
     static Core::DockWidget *dockWidgetForItem(QQuickItem *);

src/qtquick/QmlTypes.cpp

@@ -14,6 +14,7 @@
 #include "MainWindowInstantiator.h"
 #include "MainWindowMDIInstantiator.h"
 #include "LayoutSaverInstantiator.h"
+#include "Singletons_p.h"
 
 #include "views/Group.h"
 #include "views/TitleBar.h"
@@ -50,4 +51,8 @@ void KDDockWidgets::registerQmlTypes()
 
     qmlRegisterUncreatableType<QtQuick::DockWidgetModel>("com.kdab.dockwidgets", 2, 0,
                                                          "DockWidgetModel", QStringLiteral("Internal usage only"));
+
+    qmlRegisterSingletonType<QtQuick::Singletons>("com.kdab.dockwidgets", 2, 0, "Singletons", [](QQmlEngine *, QJSEngine *) -> QObject * {
+        return new QtQuick::Singletons();
+    });
 }

src/qtquick/QmlTypes.h

@@ -20,6 +20,9 @@
 #define KD_QMLTYPES_H
 
 namespace KDDockWidgets {
+// This is only called for:
+// Qt5
+// Qt6 if KDDockWidgets_QML_MODULE=OFF
 void registerQmlTypes();
 }
 

src/qtquick/Singletons.cpp

@@ -0,0 +1,40 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2025 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+  Author: Sérgio Martins <[email protected]>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <[email protected]> for commercial licensing options.
+*/
+
+#include "Singletons_p.h"
+#include "ViewFactory.h"
+#include "core/DockRegistry.h"
+#include "core/DockWidget.h"
+#include "Platform.h"
+#include "Helpers_p.h"
+
+using namespace KDDockWidgets::QtQuick;
+
+Singletons::~Singletons() = default;
+
+KDDockWidgets::QtQuick::ViewFactory *Singletons::widgetFactory() const
+{
+    return QtQuick::ViewFactory::self();
+}
+
+KDDockWidgets::DockRegistry *Singletons::dockRegistry() const
+{
+    return DockRegistry::self();
+}
+
+KDDockWidgets::QtQuickHelpers *Singletons::helpers() const
+{
+    if (auto plat = QtQuick::Platform::instance()) {
+        return plat->helpers();
+    }
+
+    return nullptr;
+}

src/qtquick/Singletons_p.h

@@ -0,0 +1,37 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2025 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+  Author: Sérgio Martins <[email protected]>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <[email protected]> for commercial licensing options.
+*/
+
+#pragma once
+
+#include "Helpers_p.h"
+#include "ViewFactory.h"
+#include "core/DockRegistry.h"
+
+#include <QQmlEngine>
+
+namespace KDDockWidgets::QtQuick {
+
+class Singletons : public QObject
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_SINGLETON
+    Q_PROPERTY(KDDockWidgets::QtQuick::ViewFactory *widgetFactory READ widgetFactory CONSTANT)
+    Q_PROPERTY(KDDockWidgets::DockRegistry *dockRegistry READ dockRegistry CONSTANT)
+    Q_PROPERTY(KDDockWidgets::QtQuickHelpers *helpers READ helpers CONSTANT)
+public:
+    ~Singletons() override;
+    KDDockWidgets::QtQuick::ViewFactory *widgetFactory() const;
+    KDDockWidgets::DockRegistry *dockRegistry() const;
+    KDDockWidgets::QtQuickHelpers *helpers() const;
+};
+
+}

src/qtquick/ViewFactory.h

@@ -14,6 +14,8 @@
 
 #include "kddockwidgets/core/ViewFactory.h"
 
+#include <QQmlEngine>
+
 // clazy:excludeall=ctor-missing-parent-argument
 
 /**
@@ -49,6 +51,7 @@ namespace QtQuick {
 class DOCKS_EXPORT ViewFactory : public Core::ViewFactory
 {
     Q_OBJECT
+    QML_ELEMENT
 public:
     ViewFactory() = default;
     ~ViewFactory() override;

src/qtquick/views/qml/FloatingWindow.qml

@@ -39,7 +39,7 @@ Rectangle {
         id: titleBar
         readonly property TitleBarView titleBarCpp: root.titleBarCpp
         readonly property int heightWhenVisible: item.heightWhenVisible // qmllint disable missing-property
-        source: _kddw_widgetFactory.titleBarFilename()
+        source: Singletons.widgetFactory.titleBarFilename()
 
         anchors {
             top: parent ? parent.top : undefined

src/qtquick/views/qml/Group.qml

@@ -22,7 +22,7 @@ Rectangle {
     property int titleBarContentsMargin: 1
     property int mouseResizeMargin: 8
     readonly property bool isMDI: groupCpp && groupCpp.isMDI
-    readonly property bool resizeAllowed: root.isMDI && !_kddwHelpers.isDragging && _kddwDockRegistry && (!_kddwHelpers.groupViewInMDIResize || _kddwHelpers.groupViewInMDIResize === groupCpp)
+    readonly property bool resizeAllowed: root.isMDI && !Singletons.helpers.isDragging && Singletons.dockRegistry && (!Singletons.helpers.groupViewInMDIResize || Singletons.helpers.groupViewInMDIResize === groupCpp)
     property alias tabBarHeight: tabbar.height
     readonly property bool hasCustomMouseEventRedirector: false
     readonly property bool isFixedHeight: groupCpp && groupCpp.isFixedHeight
@@ -176,7 +176,7 @@ Rectangle {
     Loader {
         id: titleBar
         readonly property QtObject titleBarCpp: root.titleBarCpp
-        source: groupCpp ? _kddw_widgetFactory.titleBarFilename() : ""
+        source: groupCpp ? Singletons.widgetFactory.titleBarFilename() : ""
 
         anchors {
             top: parent ? parent.top : undefined
@@ -193,7 +193,7 @@ Rectangle {
         readonly property GroupView groupCpp: root.groupCpp
         readonly property bool hasCustomMouseEventRedirector: root.hasCustomMouseEventRedirector
 
-        source: groupCpp ? _kddw_widgetFactory.tabbarFilename() : ""
+        source: groupCpp ? Singletons.widgetFactory.tabbarFilename() : ""
 
         function topAnchor() {
             if (root.tabsAtTop) {