added qml implementation for view placeholder

examples/mvvmcore/SampleCore/SampleCore.pro

@@ -12,7 +12,8 @@ HEADERS += \
 	echoservice.h \
 	resultviewmodel.h \
 	drawerviewmodel.h \
-	tabviewmodel.h
+	tabviewmodel.h \
+    containerviewmodel.h
 
 SOURCES += \
 	samplecoreapp.cpp \
@@ -20,7 +21,8 @@ SOURCES += \
 	echoservice.cpp \
 	resultviewmodel.cpp \
 	drawerviewmodel.cpp \
-	tabviewmodel.cpp
+	tabviewmodel.cpp \
+    containerviewmodel.cpp
 
 RESOURCES += \
 	sample_core.qrc

examples/mvvmcore/SampleCore/containerviewmodel.cpp

@@ -0,0 +1,31 @@
+#include "containerviewmodel.h"
+
+ContainerViewModel::ContainerViewModel(QObject *parent) :
+	ViewModel(parent)
+{}
+
+ContainerViewModel::~ContainerViewModel()
+{
+	qInfo(Q_FUNC_INFO);
+}
+
+QString ContainerViewModel::vmType() const
+{
+	return QString::fromUtf8(QMetaType::typeName(qMetaTypeId<ChildViewModel*>()));
+}
+
+void ContainerViewModel::loadChild()
+{
+	show<ChildViewModel>();
+}
+
+
+
+ChildViewModel::ChildViewModel(QObject *parent) :
+	ViewModel(parent)
+{}
+
+ChildViewModel::~ChildViewModel()
+{
+	qInfo(Q_FUNC_INFO);
+}

examples/mvvmcore/SampleCore/containerviewmodel.h

@@ -0,0 +1,34 @@
+#ifndef CONTAINERVIEWMODEL_H
+#define CONTAINERVIEWMODEL_H
+
+#include <QtMvvmCore/ViewModel>
+
+class ChildViewModel : public QtMvvm::ViewModel
+{
+	Q_OBJECT
+
+public:
+	Q_INVOKABLE explicit ChildViewModel(QObject *parent = nullptr);
+	~ChildViewModel();
+};
+
+class ContainerViewModel : public QtMvvm::ViewModel
+{
+	Q_OBJECT
+
+	Q_PROPERTY(QString vmType READ vmType CONSTANT)
+
+public:
+	Q_INVOKABLE explicit ContainerViewModel(QObject *parent = nullptr);
+	~ContainerViewModel();
+
+	QString vmType() const;
+
+public Q_SLOTS:
+	void loadChild();
+};
+
+Q_DECLARE_METATYPE(ChildViewModel*)
+Q_DECLARE_METATYPE(ContainerViewModel*)
+
+#endif // CONTAINERVIEWMODEL_H

examples/mvvmcore/SampleCore/drawerviewmodel.cpp

@@ -3,6 +3,7 @@
 
 #include "sampleviewmodel.h"
 #include "tabviewmodel.h"
+#include "containerviewmodel.h"
 
 DrawerViewModel::DrawerViewModel(QObject *parent) :
 	ViewModel(parent),
@@ -10,6 +11,7 @@ DrawerViewModel::DrawerViewModel(QObject *parent) :
 {
 	_navModel->appendRow(new QStandardItem(tr("Main Sample")));
 	_navModel->appendRow(new QStandardItem(tr("Tab Sample")));
+	_navModel->appendRow(new QStandardItem(tr("View Container Sample")));
 	_navModel->appendRow(new QStandardItem(tr("Settings")));
 }
 
@@ -35,6 +37,9 @@ void DrawerViewModel::open(int index)
 							   });
 		break;
 	case 2:
+		show<ContainerViewModel>();
+		break;
+	case 3:
 		show<QtMvvm::SettingsViewModel>();
 		break;
 	default:

examples/mvvmquick/SampleQuick/ChildView.qml

@@ -0,0 +1,29 @@
+import QtQuick 2.10
+import QtQuick.Controls 2.3
+import de.skycoder42.QtMvvm.Core 1.1
+import de.skycoder42.QtMvvm.Quick 1.1
+import de.skycoder42.QtMvvm.Sample 1.1
+
+Rectangle {
+	property ChildViewModel viewModel: null
+
+	color: "red"
+
+	property bool dummyClosed: false
+
+	function closeAction() {
+		if(dummyClosed)
+			return false;
+		else {
+			dummyClosed = true;
+			label.text = qsTr("I was closed!")
+			return true;
+		}
+	}
+
+	Label {
+		id: label
+		anchors.centerIn: parent
+		text: qsTr("I am the child!")
+	}
+}

examples/mvvmquick/SampleQuick/ContainerView.qml

@@ -0,0 +1,71 @@
+import QtQuick 2.10
+import QtQuick.Controls 2.3
+import QtQuick.Layouts 1.3
+import de.skycoder42.QtMvvm.Core 1.1
+import de.skycoder42.QtMvvm.Quick 1.1
+import de.skycoder42.QtMvvm.Sample 1.1
+
+Page {
+	id: containerView
+	property ContainerViewModel viewModel: null
+
+	function presentItem(item) {
+		return viewPlaceholder.presentItem(item);
+	}
+
+	function closeAction() {
+		return viewPlaceholder.closeAction();
+	}
+
+	header: ContrastToolBar {
+		ToolBarLabel {
+			text: qsTr("View Container")
+			anchors.fill: parent
+		}
+	}
+
+	PresenterProgress {}
+
+	Pane {
+		anchors.fill: parent
+
+		ColumnLayout {
+			anchors.fill: parent
+
+			ViewPlaceholder {
+				id: viewPlaceholder
+
+				viewModelType: containerView.viewModel.vmType
+				parentViewModel: containerView.viewModel
+				autoPresent: false
+
+				Layout.fillWidth: true
+				Layout.fillHeight: true
+
+				BusyIndicator {
+					anchors.centerIn: parent
+					anchors.verticalCenterOffset: -(hookButton.height/2)
+					running: !viewPlaceholder.loadedView
+				}
+
+				Button {
+					id: hookButton
+					Layout.fillWidth: true
+					text: qsTr("Load from QML")
+					onClicked: viewPlaceholder.presentView();
+					enabled: !viewPlaceholder.loadedView
+
+					anchors.left: parent.left
+					anchors.right: parent.right
+					anchors.bottom: parent.bottom
+				}
+			}
+
+			Button {
+				Layout.fillWidth: true
+				text: viewPlaceholder.loadedView ? qsTr("Discard child") : qsTr("Show Child")
+				onClicked: viewPlaceholder.loadedView ? viewPlaceholder.discardView() : viewModel.loadChild();
+			}
+		}
+	}
+}

examples/mvvmquick/SampleQuick/main.cpp

@@ -12,6 +12,7 @@
 #include <resultviewmodel.h>
 #include <drawerviewmodel.h>
 #include <tabviewmodel.h>
+#include <containerviewmodel.h>
 
 #include "quickeventservice.h"
 
@@ -34,6 +35,8 @@ int main(int argc, char *argv[])
 	qmlRegisterUncreatableType<DrawerViewModel>("de.skycoder42.QtMvvm.Sample", 1, 1, "DrawerViewModel", QStringLiteral("ViewModels cannot be created"));
 	qmlRegisterUncreatableType<TabViewModel>("de.skycoder42.QtMvvm.Sample", 1, 1, "TabViewModel", QStringLiteral("ViewModels cannot be created"));
 	qmlRegisterUncreatableType<TabItemViewModel>("de.skycoder42.QtMvvm.Sample", 1, 1, "TabItemViewModel", QStringLiteral("ViewModels cannot be created"));
+	qmlRegisterUncreatableType<ContainerViewModel>("de.skycoder42.QtMvvm.Sample", 1, 1, "ContainerViewModel", QStringLiteral("ViewModels cannot be created"));
+	qmlRegisterUncreatableType<ChildViewModel>("de.skycoder42.QtMvvm.Sample", 1, 1, "ChildViewModel", QStringLiteral("ViewModels cannot be created"));
 
 	QtMvvm::ServiceRegistry::instance()->registerObject<EchoService>();
 	QtMvvm::ServiceRegistry::instance()->registerInterface<IEventService, QuickEventService>();

examples/mvvmquick/SampleQuick/qml.qrc

@@ -8,5 +8,7 @@
         <file>DrawerView.qml</file>
         <file>TabView.qml</file>
         <file>TabItemView.qml</file>
+        <file>ContainerView.qml</file>
+        <file>ChildView.qml</file>
     </qresource>
 </RCC>

src/imports/mvvmquick/mvvmquick.pro

@@ -12,7 +12,8 @@ HEADERS += \
 	settingsuibuilder.h \
 	settingssectionmodel.h \
 	multifilterproxymodel.h \
-	settingsentrymodel.h
+	settingsentrymodel.h \
+	qqmlviewplaceholder.h
 
 SOURCES += \
 	qtmvvmquick_plugin.cpp \
@@ -20,7 +21,8 @@ SOURCES += \
 	settingsuibuilder.cpp \
 	settingssectionmodel.cpp \
 	multifilterproxymodel.cpp \
-	settingsentrymodel.cpp
+	settingsentrymodel.cpp \
+	qqmlviewplaceholder.cpp
 
 QML_FILES += \
 	QtMvvmApp.qml \

src/imports/mvvmquick/plugins.qmltypes

@@ -102,6 +102,61 @@ Module {
             Parameter { name: "mimeTypes"; type: "QStringList" }
         }
     }
+    Component {
+        name: "QtMvvm::QQmlViewPlaceholder"
+        defaultProperty: "data"
+        prototype: "QQuickItem"
+        exports: ["de.skycoder42.QtMvvm.Quick/ViewPlaceholder 1.1"]
+        exportMetaObjectRevisions: [0]
+        Property { name: "viewModelType"; type: "string" }
+        Property { name: "showParams"; type: "QVariantHash" }
+        Property { name: "parentViewModel"; type: "QtMvvm::ViewModel"; isPointer: true }
+        Property { name: "autoPresent"; type: "bool" }
+        Property { name: "autoResizeView"; type: "bool" }
+        Property { name: "replaceViews"; type: "bool" }
+        Property { name: "closeViewOnAction"; type: "bool" }
+        Property { name: "loadedView"; type: "QQuickItem"; isReadonly: true; isPointer: true }
+        Signal {
+            name: "viewModelTypeChanged"
+            Parameter { name: "viewModelType"; type: "string" }
+        }
+        Signal {
+            name: "showParamsChanged"
+            Parameter { name: "showParams"; type: "QVariantHash" }
+        }
+        Signal {
+            name: "parentViewModelChanged"
+            Parameter { name: "parentViewModel"; type: "QtMvvm::ViewModel"; isPointer: true }
+        }
+        Signal {
+            name: "autoPresentChanged"
+            Parameter { name: "autoPresent"; type: "bool" }
+        }
+        Signal {
+            name: "autoResizeViewChanged"
+            Parameter { name: "autoResizeView"; type: "bool" }
+        }
+        Signal {
+            name: "replaceViewsChanged"
+            Parameter { name: "replaceViews"; type: "bool" }
+        }
+        Signal {
+            name: "closeViewOnActionChanged"
+            Parameter { name: "closeViewOnAction"; type: "bool" }
+        }
+        Signal {
+            name: "loadedViewChanged"
+            Parameter { name: "loadedView"; type: "QQuickItem"; isPointer: true }
+        }
+        Method { name: "presentView" }
+        Method { name: "discardView" }
+        Method {
+            name: "presentItem"
+            type: "bool"
+            Parameter { name: "item"; type: "QVariant" }
+        }
+        Method { name: "closeAction"; type: "bool" }
+    }
     Component {
         name: "QtMvvm::SettingsUiBuilder"
         prototype: "QObject"

src/imports/mvvmquick/qqmlviewplaceholder.cpp

@@ -0,0 +1,201 @@
+#include "qqmlviewplaceholder.h"
+#include <QtCore/QMetaMethod>
+#include <QtQml/QQmlInfo>
+#include <QtQml/QQmlProperty>
+#include <QtMvvmCore/CoreApp>
+using namespace QtMvvm;
+
+QQmlViewPlaceholder::QQmlViewPlaceholder(QQuickItem *parent) :
+	QQuickItem{parent}
+{
+	// auto presenting
+	connect(this, &QQmlViewPlaceholder::viewModelTypeChanged,
+			this, &QQmlViewPlaceholder::presentIfReady);
+	connect(this, &QQmlViewPlaceholder::autoPresentChanged,
+			this, &QQmlViewPlaceholder::presentIfReady);
+
+	// size changes
+	connect(this, &QQmlViewPlaceholder::widthChanged,
+			this, &QQmlViewPlaceholder::resizeView);
+	connect(this, &QQmlViewPlaceholder::heightChanged,
+			this, &QQmlViewPlaceholder::resizeView);
+	connect(this, &QQmlViewPlaceholder::autoResizeViewChanged,
+			this, &QQmlViewPlaceholder::resizeView);
+}
+
+bool QQmlViewPlaceholder::presentItem(const QVariant &item)
+{
+	// check if the parameter is valid
+	auto quickItem = item.value<QQuickItem*>();
+	if(!quickItem) {
+		qmlWarning(this) << "presentItem called with invalid item of type " << item.typeName();
+		return false;
+	}
+
+	// handle already existing view case
+	if(_loadedView) {
+		if(_replaceViews) { // quick discard without reenableing all children
+			_loadedView->setVisible(false);
+			_loadedView->deleteLater();
+			_loadedView = nullptr;
+		} else {
+			qmlWarning(this) << R"(A view has already been presented. Discard it first via "discardView" or set "replaceViews" to true)";
+			return false;
+		}
+	}
+
+	// add
+	_loadedView = quickItem;
+	quickItem->setParent(this);
+	quickItem->setParentItem(this);
+	resizeView();
+	quickItem->setVisible(true);
+
+	// hide all children
+	for(auto child : childItems()) {
+		if(child != _loadedView)
+			child->setVisible(false);
+	}
+
+	emit loadedViewChanged(_loadedView);
+	return true;
+}
+
+bool QQmlViewPlaceholder::closeAction()
+{
+	if(!_loadedView)
+		return false;
+
+	// call close on the view
+	auto vMetaObject = _loadedView->metaObject();
+	auto cMethodIndex = vMetaObject->indexOfMethod("closeAction()");
+	if(cMethodIndex != -1) {
+		auto cMethod = vMetaObject->method(cMethodIndex);
+		QVariant ok = false;
+		cMethod.invoke(_loadedView, Q_RETURN_ARG(QVariant, ok));
+		if(ok.toBool())
+			return true;
+	}
+
+	// close the view itself (if wished)
+	if(_closeViewOnAction) {
+		discardView();
+		return true;
+	}
+
+	// otherwise: nothing closed
+	return false;
+}
+
+void QQmlViewPlaceholder::setParentViewModel(ViewModel *parentViewModel)
+{
+	// first: clear the auto-connected viewmodel, if required
+	if(_clearParentVmCon && _parentVmCon)
+		disconnect(_parentVmCon);
+
+	// then: set property as usual
+	if(_parentViewModel == parentViewModel)
+		return;
+
+	_parentViewModel = parentViewModel;
+	emit parentViewModelChanged(_parentViewModel);
+
+	// check the vm parent for a presenter method
+	auto view = qobject_cast<QQuickItem*>(_parentViewModel->parent());
+	if(view) {
+		if(view->metaObject()->indexOfMethod("presentItem(QVariant)") == -1)
+			qmlWarning(this) << R"(Parent item of "parentViewModel" does not have a "presentItem" method. Check the ViewPlaceholder documentation!)";
+	} else
+		qmlWarning(this) << R"(Parent item of "parentViewModel" is not an Item)";
+
+	presentIfReady();
+}
+
+QQuickItem *QQmlViewPlaceholder::loadedView() const
+{
+	return _loadedView;
+}
+
+void QQmlViewPlaceholder::componentComplete()
+{
+	// auto-set the vm if not already set
+	if(!_parentViewModel)
+		getParentViewModel();
+
+	// last step: call base implementation, then present
+	QQuickItem::componentComplete();
+	_isReady = true;
+	presentIfReady();
+}
+
+void QQmlViewPlaceholder::presentView()
+{
+	CoreApp::show(qUtf8Printable(_viewModelType), _showParams, _parentViewModel);
+}
+
+void QQmlViewPlaceholder::discardView()
+{
+	// hide view
+	_loadedView->setVisible(false);
+
+	// show all children again
+	for(auto child : childItems()) {
+		if(child != _loadedView)
+			child->setVisible(true);
+	}
+
+	// now delete it
+	_loadedView->deleteLater();
+	_loadedView = nullptr;
+	emit loadedViewChanged(nullptr);
+}
+
+void QQmlViewPlaceholder::parentItemVmChanged(ViewModel *viewModel)
+{
+	// set vm without clearing the connection
+	_clearParentVmCon = false;
+	setParentViewModel(viewModel);
+	_clearParentVmCon = true;
+}
+
+void QQmlViewPlaceholder::presentIfReady()
+{
+	if(_isReady &&
+	   _autoPresent &&
+	   !_loadedView &&
+	   _parentViewModel &&
+	   !_viewModelType.isEmpty())
+		presentView();
+}
+
+void QQmlViewPlaceholder::resizeView()
+{
+	if(_loadedView && _autoResizeView) {
+		_loadedView->setWidth(width());
+		_loadedView->setHeight(height());
+	}
+}
+
+void QQmlViewPlaceholder::getParentViewModel()
+{
+	auto pItem = parentItem();
+	if(!pItem)
+		return;
+
+	QQmlProperty vmProp{pItem, QStringLiteral("viewModel")};
+	if(!vmProp.isValid())
+		return;
+
+	// set the vm from the property
+	auto vm = vmProp.read().value<ViewModel*>();
+	if(vm)
+		setParentViewModel(vm); // no warning here - might be ok for lazy presented vms
+
+	// connect to further changes, via helper slot
+	auto cSlotIndex = metaObject()->indexOfSlot("parentItemVmChanged(QtMvvm::ViewModel*)");
+	Q_ASSERT(cSlotIndex != -1);
+	if(_parentVmCon)
+		disconnect(_parentVmCon);
+	_parentVmCon = connect(pItem, vmProp.property().notifySignal(),
+						   this, metaObject()->method(cSlotIndex));
+}

src/imports/mvvmquick/qqmlviewplaceholder.h

@@ -0,0 +1,77 @@
+#ifndef QTMVVM_QQMLVIEWPLACEHOLDER_H
+#define QTMVVM_QQMLVIEWPLACEHOLDER_H
+
+#include <QtQuick/QQuickItem>
+
+#include <QtMvvmCore/ViewModel>
+
+namespace QtMvvm {
+
+class QQmlViewPlaceholder : public QQuickItem
+{
+	Q_OBJECT
+
+	Q_PROPERTY(QString viewModelType MEMBER _viewModelType NOTIFY viewModelTypeChanged)
+	Q_PROPERTY(QVariantHash showParams MEMBER _showParams NOTIFY showParamsChanged)
+	Q_PROPERTY(QtMvvm::ViewModel* parentViewModel MEMBER _parentViewModel WRITE setParentViewModel NOTIFY parentViewModelChanged)
+	Q_PROPERTY(bool autoPresent MEMBER _autoPresent NOTIFY autoPresentChanged)
+	Q_PROPERTY(bool autoResizeView MEMBER _autoResizeView NOTIFY autoResizeViewChanged)
+	Q_PROPERTY(bool replaceViews MEMBER _replaceViews NOTIFY replaceViewsChanged)
+	Q_PROPERTY(bool closeViewOnAction MEMBER _closeViewOnAction NOTIFY closeViewOnActionChanged)
+
+	Q_PROPERTY(QQuickItem* loadedView READ loadedView NOTIFY loadedViewChanged)
+
+public:
+	explicit QQmlViewPlaceholder(QQuickItem *parent = nullptr);
+
+	Q_INVOKABLE bool presentItem(const QVariant &item);
+	Q_INVOKABLE bool closeAction();
+
+	void setParentViewModel(ViewModel *parentViewModel);
+	QQuickItem* loadedView() const;
+
+	void componentComplete() override;
+
+public Q_SLOTS:
+	void presentView();
+	void discardView();
+
+Q_SIGNALS:
+	void viewModelTypeChanged(const QString &viewModelType);
+	void showParamsChanged(const QVariantHash &showParams);
+	void parentViewModelChanged(QtMvvm::ViewModel* parentViewModel);
+	void autoPresentChanged(bool autoPresent);
+	void autoResizeViewChanged(bool autoResizeView);
+	void replaceViewsChanged(bool replaceViews);
+	void closeViewOnActionChanged(bool closeViewOnAction);
+	void loadedViewChanged(QQuickItem* loadedView);
+
+private Q_SLOTS:
+	void parentItemVmChanged(QtMvvm::ViewModel *viewModel);
+	void presentIfReady();
+
+	void resizeView();
+
+private:
+	QString _viewModelType;
+	QVariantHash _showParams;
+	ViewModel *_parentViewModel = nullptr;
+	bool _autoPresent = true;
+	bool _autoResizeView = true;
+	bool _replaceViews = false;
+	bool _closeViewOnAction = false;
+
+	QPointer<QQuickItem> _loadedView = nullptr;
+
+	bool _isReady = false;
+	bool _clearParentVmCon = true;
+	QMetaObject::Connection _parentVmCon;
+
+	void getParentViewModel();
+	void connectSizeChanges();
+	void disconnectSizeChanges();
+};
+
+}
+
+#endif // QTMVVM_QQMLVIEWPLACEHOLDER_H

src/imports/mvvmquick/qtmvvmquick_plugin.cpp

@@ -6,6 +6,7 @@
 
 #include "qqmlquickpresenter.h"
 #include "settingsuibuilder.h"
+#include "qqmlviewplaceholder.h"
 #ifdef Q_OS_ANDROID
 #include "androidfilechooser.h"
 #endif
@@ -49,7 +50,7 @@ void QtMvvmQuickDeclarativeModule::registerTypes(const char *uri)
 #endif
 
 	//Version 1.1
-	qmlRegisterModule(uri, 1, 1);
+	qmlRegisterType<QtMvvm::QQmlViewPlaceholder>(uri, 1, 1, "ViewPlaceholder");
 
 	// Check to make shure no module update is forgotten
 	static_assert(VERSION_MAJOR == 1 && VERSION_MINOR == 1, "QML module version needs to be updated");

src/mvvmcore/coreapp.cpp

@@ -35,11 +35,12 @@ void CoreApp::registerApp()
 	qRegisterMetaType<const QMetaObject*>("const QMetaObject*");
 	qRegisterMetaType<MessageConfig::StandardButton>();
 
-	qRegisterMetaType<QtMvvm::SettingsElements::Entry>();
+	qRegisterMetaType<ViewModel*>();
-	qRegisterMetaType<QtMvvm::SettingsElements::Group>();
+	qRegisterMetaType<SettingsElements::Entry>();
-	qRegisterMetaType<QtMvvm::SettingsElements::Section>();
+	qRegisterMetaType<SettingsElements::Group>();
-	qRegisterMetaType<QtMvvm::SettingsElements::Category>();
+	qRegisterMetaType<SettingsElements::Section>();
-	qRegisterMetaType<QtMvvm::SettingsElements::Setup>();
+	qRegisterMetaType<SettingsElements::Category>();
+	qRegisterMetaType<SettingsElements::Setup>();
 
 	registerInterfaceConverter<IPresenter>();
 
@@ -56,6 +57,11 @@ void CoreApp::registerApp()
 }
 
 void CoreApp::show(const char *viewModelName, const QVariantHash &params)
+{
+	show(viewModelName, params, nullptr);
+}
+
+void CoreApp::show(const char *viewModelName, const QVariantHash &params, QPointer<ViewModel> parentViewModel)
 {
 	auto metaId = QMetaType::type(viewModelName);
 	auto metaObject = QMetaType::metaObjectForType(metaId);
@@ -64,17 +70,22 @@ void CoreApp::show(const char *viewModelName, const QVariantHash &params)
 								 viewModelName +
 								 QByteArrayLiteral(") does not name a type with meta data"));
 	}
-	show(metaObject, params);
+	show(metaObject, params, std::move(parentViewModel));
 }
 
 void CoreApp::show(const QMetaObject *viewModelMetaObject, const QVariantHash &params)
+{
+	show(viewModelMetaObject, params, nullptr);
+}
+
+void CoreApp::show(const QMetaObject *viewModelMetaObject, const QVariantHash &params, QPointer<ViewModel> parentViewModel)
 {
 	if(!viewModelMetaObject->inherits(&ViewModel::staticMetaObject)) {
 		throw PresenterException(QByteArrayLiteral("Given type (") +
 								 viewModelMetaObject->className() +
 								 QByteArrayLiteral(") is not a class that extends QtMvvm::ViewModel"));
 	}
-	showImp(viewModelMetaObject, params);
+	showImp(viewModelMetaObject, params, std::move(parentViewModel));
 }
 
 MessageResult *CoreApp::showDialog(const MessageConfig &config)
@@ -152,11 +163,16 @@ bool CoreApp::autoParse(QCommandLineParser &parser, const QStringList &arguments
 }
 
 void CoreApp::showImp(const QMetaObject *metaObject, const QVariantHash &params)
+{
+	showImp(metaObject, params, nullptr);
+}
+
+void CoreApp::showImp(const QMetaObject *metaObject, const QVariantHash &params, QPointer<ViewModel> parentViewModel)
 {
 	QMetaObject::invokeMethod(CoreAppPrivate::dInstance().data(), "showViewModel", Qt::QueuedConnection,
 							  Q_ARG(const QMetaObject*, metaObject),
 							  Q_ARG(QVariantHash, params),
-							  Q_ARG(QPointer<ViewModel>, nullptr),
+							  Q_ARG(QPointer<ViewModel>, std::move(parentViewModel)),
 							  Q_ARG(quint32, 0));
 }
 

src/mvvmcore/coreapp.h

@@ -36,11 +36,13 @@ public:
 
 	//! Show a new ViewModel by its type
 	template <typename TViewModel>
-	static inline void show(const QVariantHash &params = {});
+	static inline void show(const QVariantHash &params = {}, QPointer<ViewModel> parentViewModel = nullptr);
 	//! Show a new ViewModel by its name
-	static void show(const char *viewModelName, const QVariantHash &params = {});
+	static void show(const char *viewModelName, const QVariantHash &params = {}); //MAJOR merge methods
+	static void show(const char *viewModelName, const QVariantHash &params, QPointer<ViewModel> parentViewModel);
 	//! Show a new ViewModel by its metaobject
-	static void show(const QMetaObject *viewModelMetaObject, const QVariantHash &params = {});
+	static void show(const QMetaObject *viewModelMetaObject, const QVariantHash &params = {}); //MAJOR merge methods
+	static void show(const QMetaObject *viewModelMetaObject, const QVariantHash &params, QPointer<ViewModel> parentViewModel);
 
 	//! Show a basic dialog
 	static MessageResult *showDialog(const MessageConfig &config);
@@ -68,14 +70,15 @@ private:
 	friend class QtMvvm::CoreAppPrivate;
 	QScopedPointer<CoreAppPrivate> d;
 
-	static void showImp(const QMetaObject *metaObject, const QVariantHash &params);
+	Q_DECL_DEPRECATED static void showImp(const QMetaObject *metaObject, const QVariantHash &params);
+	static void showImp(const QMetaObject *metaObject, const QVariantHash &params, QPointer<ViewModel> parentViewModel);
 };
 
 template<typename TViewModel>
-inline void CoreApp::show(const QVariantHash &params)
+inline void CoreApp::show(const QVariantHash &params, QPointer<ViewModel> parentViewModel)
 {
 	static_assert(std::is_base_of<ViewModel, TViewModel>::value, "TViewModel must extend QtMvvm::ViewModel");
-	ViewModel::showImp(&TViewModel::staticMetaObject, params, nullptr);
+	showImp(&TViewModel::staticMetaObject, params, std::move(parentViewModel));
 }
 
 }

src/mvvmcore/viewmodel.h

@@ -87,4 +87,6 @@ void ViewModel::showForResult(quint32 requestCode, QVariantHash params) const
 
 }
 
+Q_DECLARE_METATYPE(QtMvvm::ViewModel*)
+
 #endif // QTMVVM_VIEWMODEL_H