Enable nested MapItemViews

This change allows MapItemView to use a MapItem, MapItemGroup or
MapItemView as delegate.
To achieve this, MapItemView base class also changes from QObject to
MapItemGroup, effectively making MapItemView a MapItemGroup.
Note, though, that MapItemGroup API in Map should be avoided, when
dealing with a MapItemView, and only MapItemView-specific API should be
used.

Tests and example coming after

[ChangeLog][QtLocation] Enabled nesting of MapItemView. This
required a behavioral change, as MapItemView is now a MapItemGroup,
not anymore a plain QObject.
Due to a bug, MapItemView was previously not a Qt Quick Item, making
it possible to create it as a child of any QObject. This has now been
fixed, so if you happen to have a MapItemView in your scene which is
not a child of a Qt Quick Item, you will get an error message.

Task-number: QTBUG-62683
Task-number: QTBUG-62397
Change-Id: Id97e480429e7f952a541fe88df5c01317afeac18
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

12 files changed, 768 insertions, 325 deletions

diff --git a/src/location/declarativemaps/declarativemaps.pri b/src/location/declarativemaps/declarativemaps.pri
index 3cd7a529..28001f99 100644
--- a/src/location/declarativemaps/declarativemaps.pri
+++ b/src/location/declarativemaps/declarativemaps.pri
@@ -3,61 +3,64 @@ QT += quick-private network positioning-private qml-private core-private gui-pri
 INCLUDEPATH += declarativemaps
 
 PRIVATE_HEADERS += \
-           declarativemaps/error_messages_p.h \
-           declarativemaps/qdeclarativegeomapitemview_p.h \
-           declarativemaps/qdeclarativegeoserviceprovider_p.h \
-           declarativemaps/qdeclarativegeocodemodel_p.h \
-           declarativemaps/qdeclarativegeoroutemodel_p.h \
-           declarativemaps/qdeclarativegeoroute_p.h \
-           declarativemaps/qdeclarativegeoroutesegment_p.h \
-           declarativemaps/qdeclarativegeomaneuver_p.h \
-           declarativemaps/qdeclarativegeomap_p.h \
-           declarativemaps/qdeclarativegeomaptype_p.h \
-           declarativemaps/qdeclarativegeomapitembase_p.h \
-           declarativemaps/qdeclarativegeomapquickitem_p.h \
-           declarativemaps/qdeclarativecirclemapitem_p.h \
-           declarativemaps/qdeclarativerectanglemapitem_p.h \
-           declarativemaps/qdeclarativepolygonmapitem_p.h \
-           declarativemaps/qdeclarativepolylinemapitem_p.h \
-           declarativemaps/qdeclarativeroutemapitem_p.h \
-           declarativemaps/qdeclarativegeomapparameter_p.h \
-           declarativemaps/qgeomapitemgeometry_p.h \
-           declarativemaps/qdeclarativegeomapcopyrightsnotice_p.h \
-           declarativemaps/locationvaluetypehelper_p.h \
-           declarativemaps/qquickgeomapgesturearea_p.h \
-           declarativemaps/qdeclarativegeomapitemgroup_p.h \
-           declarativemaps/qparameterizableobject_p.h \
-           declarativemaps/qgeomapobject_p.h \
-           declarativemaps/qgeomapobject_p_p.h \
-           ../imports/positioning/qquickgeocoordinateanimation_p.h
+        declarativemaps/error_messages_p.h \
+        declarativemaps/locationvaluetypehelper_p.h \
+        declarativemaps/mapitemviewdelegateincubator_p.h \
+        declarativemaps/qdeclarativecirclemapitem_p.h \
+        declarativemaps/qdeclarativegeocodemodel_p.h \
+        declarativemaps/qdeclarativegeomaneuver_p.h \
+        declarativemaps/qdeclarativegeomapcopyrightsnotice_p.h \
+        declarativemaps/qdeclarativegeomapitembase_p.h \
+        declarativemaps/qdeclarativegeomapitemgroup_p.h \
+        declarativemaps/qdeclarativegeomapitemtransitionmanager_p.h \
+        declarativemaps/qdeclarativegeomapitemview_p.h \
+        declarativemaps/qdeclarativegeomapparameter_p.h \
+        declarativemaps/qdeclarativegeomap_p.h \
+        declarativemaps/qdeclarativegeomapquickitem_p.h \
+        declarativemaps/qdeclarativegeomaptype_p.h \
+        declarativemaps/qdeclarativegeoroutemodel_p.h \
+        declarativemaps/qdeclarativegeoroute_p.h \
+        declarativemaps/qdeclarativegeoroutesegment_p.h \
+        declarativemaps/qdeclarativegeoserviceprovider_p.h \
+        declarativemaps/qdeclarativepolygonmapitem_p.h \
+        declarativemaps/qdeclarativepolylinemapitem_p.h \
+        declarativemaps/qdeclarativerectanglemapitem_p.h \
+        declarativemaps/qdeclarativeroutemapitem_p.h \
+        declarativemaps/qgeomapitemgeometry_p.h \
+        declarativemaps/qgeomapobject_p.h \
+        declarativemaps/qgeomapobject_p_p.h \
+        declarativemaps/qparameterizableobject_p.h \
+        declarativemaps/qquickgeomapgesturearea_p.h \
+        ../imports/positioning/qquickgeocoordinateanimation_p.h
 
 SOURCES += \
-           declarativemaps/qdeclarativegeomapitemview.cpp \
-           declarativemaps/qdeclarativegeoserviceprovider.cpp \
-           declarativemaps/qdeclarativegeocodemodel.cpp \
-           declarativemaps/qdeclarativegeoroutemodel.cpp \
-           declarativemaps/qdeclarativegeoroute.cpp \
-           declarativemaps/qdeclarativegeoroutesegment.cpp \
-           declarativemaps/qdeclarativegeomaneuver.cpp \
-           declarativemaps/qdeclarativegeomap.cpp \
-           declarativemaps/qdeclarativegeomaptype.cpp \
-           declarativemaps/qdeclarativegeomapitembase.cpp \
-           declarativemaps/qdeclarativegeomapquickitem.cpp \
-           declarativemaps/qdeclarativecirclemapitem.cpp \
-           declarativemaps/qdeclarativerectanglemapitem.cpp \
-           declarativemaps/qdeclarativepolygonmapitem.cpp \
-           declarativemaps/qdeclarativepolylinemapitem.cpp \
-           declarativemaps/qdeclarativeroutemapitem.cpp \
-           declarativemaps/qdeclarativegeomapparameter.cpp \
-           declarativemaps/qgeomapitemgeometry.cpp \
-           declarativemaps/qdeclarativegeomapcopyrightsnotice.cpp \
-           declarativemaps/error_messages.cpp \
-           declarativemaps/locationvaluetypehelper.cpp \
-           declarativemaps/qquickgeomapgesturearea.cpp \
-           declarativemaps/qparameterizableobject.cpp \
-           declarativemaps/qdeclarativegeomapitemgroup.cpp \
-           declarativemaps/qgeomapobject.cpp \
-           ../imports/positioning/qquickgeocoordinateanimation.cpp
+        declarativemaps/error_messages.cpp \
+        declarativemaps/locationvaluetypehelper.cpp \
+        declarativemaps/qdeclarativecirclemapitem.cpp \
+        declarativemaps/qdeclarativegeocodemodel.cpp \
+        declarativemaps/qdeclarativegeomaneuver.cpp \
+        declarativemaps/qdeclarativegeomapcopyrightsnotice.cpp \
+        declarativemaps/qdeclarativegeomap.cpp \
+        declarativemaps/qdeclarativegeomapitembase.cpp \
+        declarativemaps/qdeclarativegeomapitemgroup.cpp \
+        declarativemaps/qdeclarativegeomapitemtransitionmanager.cpp \
+        declarativemaps/qdeclarativegeomapitemview.cpp \
+        declarativemaps/qdeclarativegeomapparameter.cpp \
+        declarativemaps/qdeclarativegeomapquickitem.cpp \
+        declarativemaps/qdeclarativegeomaptype.cpp \
+        declarativemaps/qdeclarativegeoroute.cpp \
+        declarativemaps/qdeclarativegeoroutemodel.cpp \
+        declarativemaps/qdeclarativegeoroutesegment.cpp \
+        declarativemaps/qdeclarativegeoserviceprovider.cpp \
+        declarativemaps/qdeclarativepolygonmapitem.cpp \
+        declarativemaps/qdeclarativepolylinemapitem.cpp \
+        declarativemaps/qdeclarativerectanglemapitem.cpp \
+        declarativemaps/qdeclarativeroutemapitem.cpp \
+        declarativemaps/qgeomapitemgeometry.cpp \
+        declarativemaps/qgeomapobject.cpp \
+        declarativemaps/qparameterizableobject.cpp \
+        declarativemaps/qquickgeomapgesturearea.cpp \
+        ../imports/positioning/qquickgeocoordinateanimation.cpp
 
 load(qt_build_paths)
 LIBS_PRIVATE += -L$$MODULE_BASE_OUTDIR/lib -lpoly2tri$$qtPlatformTargetSuffix() -lclip2tri$$qtPlatformTargetSuffix()
diff --git a/src/location/declarativemaps/qdeclarativegeomap.cpp b/src/location/declarativemaps/qdeclarativegeomap.cpp
index d201b6ab..00643ea1 100644
--- a/src/location/declarativemaps/qdeclarativegeomap.cpp
+++ b/src/location/declarativemaps/qdeclarativegeomap.cpp
@@ -240,10 +240,13 @@ QDeclarativeGeoMap::~QDeclarativeGeoMap()
         for (QDeclarativeGeoMapItemView *v : qAsConst(m_mapViews)) {
             if (!v)
                 continue;
-            if (v->parent() == this)
+            if (v->parent() == this) {
                 delete v;
-            else
-                v->removeInstantiatedItems();
+            } else {
+                // FIXME: removeInstantiatedItems should abort, as well as exit transitions terminated
+                v->removeInstantiatedItems(false);
+                v->m_map = nullptr;
+            }
         }
     }
     // remove any map items associations
@@ -251,19 +254,12 @@ QDeclarativeGeoMap::~QDeclarativeGeoMap()
         if (m_mapItems.at(i))
             m_mapItems.at(i).data()->setMap(0,0);
     }
-    m_mapItems.clear();
 
-    for (auto g: qAsConst(m_mapItemGroups)) {
-        if (!g)
-            continue;
-        const QList<QQuickItem *> quickKids = g->childItems();
-        for (auto c: quickKids) {
-            QDeclarativeGeoMapItemBase *itemBase = qobject_cast<QDeclarativeGeoMapItemBase *>(c);
-            if (itemBase)
-                itemBase->setMap(0,0);
-        }
+    // remove any map item groups associations
+    for (int i = 0; i < m_mapItemGroups.count(); ++i) {
+        if (m_mapItemGroups.at(i))
+            m_mapItemGroups.at(i).data()->setQuickMap(nullptr);
     }
-    m_mapItemGroups.clear();
 
     if (m_copyrights.data())
         delete m_copyrights.data();
@@ -470,28 +466,7 @@ void QDeclarativeGeoMap::populateMap()
         kids.insert(ite);
 
     for (QObject *k : qAsConst(kids)) {
-        // dispatch items appropriately
-        QDeclarativeGeoMapItemView *mapView = qobject_cast<QDeclarativeGeoMapItemView *>(k);
-        if (mapView) {
-            m_mapViews.append(mapView);
-            setupMapView(mapView);
-            continue;
-        }
-        QDeclarativeGeoMapItemBase *mapItem = qobject_cast<QDeclarativeGeoMapItemBase *>(k);
-        if (mapItem) {
-            addMapItem(mapItem);
-            continue;
-        }
-        // Allow to add to the map Map items contained inside a parent QQuickItem, but only those at one level of nesting.
-        QDeclarativeGeoMapItemGroup *itemGroup = qobject_cast<QDeclarativeGeoMapItemGroup *>(k);
-        if (itemGroup) {
-            addMapItemGroup(itemGroup);
-            continue;
-        }
-
-        QGeoMapObject *mapObject = qobject_cast<QGeoMapObject *>(k);
-        if (mapObject)
-            addMapObject(mapObject);
+        addMapChild(k);
     }
 }
 
@@ -751,15 +726,9 @@ void QDeclarativeGeoMap::mappingManagerInitialized()
     }
 
     // Any map item groups that were added before the plugin was ready
-    // need to have setMap called again on their children map items
-    for (auto g: qAsConst(m_mapItemGroups)) {
-        const QList<QQuickItem *> quickKids = g->childItems();
-        for (auto c: quickKids) {
-            QDeclarativeGeoMapItemBase *itemBase = qobject_cast<QDeclarativeGeoMapItemBase *>(c);
-            if (itemBase)
-                itemBase->setMap(this, m_map);
-        }
-    }
+    // DO NOT need to have setMap called again on their children map items
+    // because they have been added to m_mapItems, which is processed right above.
+
 
     // All map parameters that were added before the plugin was ready
     // need to be added to m_map
@@ -943,6 +912,58 @@ void QDeclarativeGeoMap::setZoomLevel(qreal zoomLevel, bool overzoom)
         emit zoomLevelChanged(m_cameraData.zoomLevel());
 }
 
+bool QDeclarativeGeoMap::addMapChild(QObject *child)
+{
+    // dispatch items appropriately
+    QDeclarativeGeoMapItemView *mapView = qobject_cast<QDeclarativeGeoMapItemView *>(child);
+    if (mapView)
+        return addMapItemView_real(mapView);
+
+    QDeclarativeGeoMapItemGroup *itemGroup = qobject_cast<QDeclarativeGeoMapItemGroup *>(child);
+    if (itemGroup) // addMapItemView calls addMapItemGroup
+        return addMapItemGroup_real(itemGroup);
+
+    QDeclarativeGeoMapItemBase *mapItem = qobject_cast<QDeclarativeGeoMapItemBase *>(child);
+    if (mapItem)
+        return addMapItem_real(mapItem);
+
+    QGeoMapObject *mapObject = qobject_cast<QGeoMapObject *>(child);
+    if (mapObject)
+        addMapObject(mapObject); // this emits mapObjectsChanged, != mapItemsChanged
+    return false;
+}
+
+bool QDeclarativeGeoMap::removeMapChild(QObject *child)
+{
+    // dispatch items appropriately
+    QDeclarativeGeoMapItemView *mapView = qobject_cast<QDeclarativeGeoMapItemView *>(child);
+    if (mapView)
+        return removeMapItemView_real(mapView);
+
+    QDeclarativeGeoMapItemGroup *itemGroup = qobject_cast<QDeclarativeGeoMapItemGroup *>(child);
+    if (itemGroup) // removeMapItemView calls removeMapItemGroup for itself.
+        return removeMapItemGroup_real(itemGroup);
+
+    QDeclarativeGeoMapItemBase *mapItem = qobject_cast<QDeclarativeGeoMapItemBase *>(child);
+    if (mapItem)
+        return removeMapItem_real(mapItem);
+
+    QGeoMapObject *mapObject = qobject_cast<QGeoMapObject *>(child);
+    if (mapObject)
+        removeMapObject(mapObject); // this emits mapObjectsChanged, != mapItemsChanged
+    return false;
+}
+
+bool QDeclarativeGeoMap::isGroupNested(QDeclarativeGeoMapItemGroup *group)
+{
+    QObject *parent = group->parent();
+    // Nested groups have parent set in parent's componentComplete()
+    // Those instantiated by MapItemView's delegateModel, however, do not,
+    // but have setParentItem set.
+    return qobject_cast<QDeclarativeGeoMapItemGroup *>(parent)
+            || qobject_cast<QDeclarativeGeoMapItemGroup *>(group->parentItem());
+}
+
 qreal QDeclarativeGeoMap::zoomLevel() const
 {
     return m_cameraData.zoomLevel();
@@ -1708,39 +1729,6 @@ void QDeclarativeGeoMap::onAttachedCopyrightNoticeVisibilityChanged()
 }
 
 /*!
-    \qmlmethod void QtLocation::Map::addMapItem(MapItem item)
-
-    Adds the given \a item to the Map (for example MapQuickItem, MapCircle). If the object
-    already is on the Map, it will not be added again.
-
-    As an example, consider the case where you have a MapCircle representing your current position:
-
-    \snippet declarative/maps.qml QtQuick import
-    \snippet declarative/maps.qml QtLocation import
-    \codeline
-    \snippet declarative/maps.qml Map addMapItem MapCircle at current position
-
-    \note MapItemViews cannot be added with this method.
-
-    \sa mapItems, removeMapItem, clearMapItems
-*/
-
-void QDeclarativeGeoMap::addMapItem(QDeclarativeGeoMapItemBase *item)
-{
-    if (!item || item->quickMap())
-        return;
-    // If the item comes from a MapItemGroup, do not reparent it.
-    if (!qobject_cast<QDeclarativeGeoMapItemGroup *>(item->parentItem()))
-        item->setParentItem(this);
-    m_mapItems.append(item);
-    if (m_map) {
-        item->setMap(this, m_map);
-        m_map->addMapItem(item);
-    }
-    emit mapItemsChanged();
-}
-
-/*!
     \qmlmethod void QtLocation::Map::addMapParameter(MapParameter parameter)
 
     Adds a MapParameter object to the map. The effect of this call is dependent
@@ -1920,6 +1908,45 @@ QList<QObject *> QDeclarativeGeoMap::mapItems()
 }
 
 /*!
+    \qmlmethod void QtLocation::Map::addMapItem(MapItem item)
+
+    Adds the given \a item to the Map (for example MapQuickItem, MapCircle). If the object
+    already is on the Map, it will not be added again.
+
+    As an example, consider the case where you have a MapCircle representing your current position:
+
+    \snippet declarative/maps.qml QtQuick import
+    \snippet declarative/maps.qml QtLocation import
+    \codeline
+    \snippet declarative/maps.qml Map addMapItem MapCircle at current position
+
+    \note MapItemViews cannot be added with this method.
+
+    \sa mapItems, removeMapItem, clearMapItems
+*/
+
+void QDeclarativeGeoMap::addMapItem(QDeclarativeGeoMapItemBase *item)
+{
+    if (addMapItem_real(item))
+        emit mapItemsChanged();
+}
+
+bool QDeclarativeGeoMap::addMapItem_real(QDeclarativeGeoMapItemBase *item)
+{
+    if (!item || item->quickMap())
+        return false;
+    // If the item comes from a MapItemGroup, do not reparent it.
+    if (!qobject_cast<QDeclarativeGeoMapItemGroup *>(item->parentItem()))
+        item->setParentItem(this);
+    m_mapItems.append(item);
+    if (m_map) {
+        item->setMap(this, m_map);
+        m_map->addMapItem(item);
+    }
+    return true;
+}
+
+/*!
     \qmlmethod void QtLocation::Map::removeMapItem(MapItem item)
 
     Removes the given \a item from the Map (for example MapQuickItem, MapCircle). If
@@ -1930,18 +1957,25 @@ QList<QObject *> QDeclarativeGeoMap::mapItems()
 */
 void QDeclarativeGeoMap::removeMapItem(QDeclarativeGeoMapItemBase *ptr)
 {
-    if (!ptr || !m_map)
-        return;
-    m_map->removeMapItem(ptr);
+    if (removeMapItem_real(ptr))
+        emit mapItemsChanged();
+}
+
+bool QDeclarativeGeoMap::removeMapItem_real(QDeclarativeGeoMapItemBase *ptr)
+{
+    if (!ptr)
+        return false;
     QPointer<QDeclarativeGeoMapItemBase> item(ptr);
     if (!m_mapItems.contains(item))
-        return;
+        return false;
+    if (m_map)
+        m_map->removeMapItem(ptr);
     if (item->parentItem() == this)
         item->setParentItem(0);
     item->setMap(0, 0);
     // these can be optimized for perf, as we already check the 'contains' above
     m_mapItems.removeOne(item);
-    emit mapItemsChanged();
+    return true;
 }
 
 /*!
@@ -1955,18 +1989,25 @@ void QDeclarativeGeoMap::clearMapItems()
 {
     if (m_mapItems.isEmpty())
         return;
-    if (m_map)
-        m_map->clearMapItems();
-    for (auto i : qAsConst(m_mapItems)) {
-        if (i) {
-            i->setMap(0, 0);
-            if (i->parentItem() == this)
-                i->setParentItem(0);
-        }
+
+    int removed = 0;
+    for (auto i : qAsConst(m_mapItemGroups)) {
+        // Processing only top-level groups (!views)
+        QDeclarativeGeoMapItemView *view = qobject_cast<QDeclarativeGeoMapItemView *>(i);
+        if (view)
+            continue;
+
+        if (i->parentItem() != this)
+            continue;
+
+        removed += removeMapItemGroup_real(i);
     }
-    m_mapItems.clear();
-    m_mapItemGroups.clear();
-    emit mapItemsChanged();
+
+    for (auto i : qAsConst(m_mapItems))
+        removed += removeMapItem_real(i);
+
+    if (removed)
+        emit mapItemsChanged();
 }
 
 /*!
@@ -1981,19 +2022,29 @@ void QDeclarativeGeoMap::clearMapItems()
 */
 void QDeclarativeGeoMap::addMapItemGroup(QDeclarativeGeoMapItemGroup *itemGroup)
 {
-    if (!itemGroup || itemGroup->quickMap()) // || Already added to some map
-        return;
+    if (addMapItemGroup_real(itemGroup))
+        emit mapItemsChanged();
+}
+
+bool QDeclarativeGeoMap::addMapItemGroup_real(QDeclarativeGeoMapItemGroup *itemGroup)
+{
+    if (!itemGroup || itemGroup->quickMap()) // Already added to some map
+        return false;
 
     itemGroup->setQuickMap(this);
+
+    if (!isGroupNested(itemGroup))
+        itemGroup->setParentItem(this);
+
     QPointer<QDeclarativeGeoMapItemGroup> g(itemGroup);
     m_mapItemGroups.append(g);
-    const QList<QQuickItem *> quickKids = g->childItems();
+
+    const QList<QQuickItem *> quickKids = itemGroup->childItems();
+    int count = 0;
     for (auto c: quickKids) {
-        QDeclarativeGeoMapItemBase *mapItem = qobject_cast<QDeclarativeGeoMapItemBase *>(c);
-        if (mapItem)
-            addMapItem(mapItem);
+        count += addMapChild(c); // this calls addMapItemGroup recursively, if needed
     }
-    itemGroup->setParentItem(this);
+    return count;
 }
 
 /*!
@@ -2007,21 +2058,28 @@ void QDeclarativeGeoMap::addMapItemGroup(QDeclarativeGeoMapItemGroup *itemGroup)
 */
 void QDeclarativeGeoMap::removeMapItemGroup(QDeclarativeGeoMapItemGroup *itemGroup)
 {
+    if (removeMapItemGroup_real(itemGroup))
+        emit mapItemsChanged();
+}
+
+bool QDeclarativeGeoMap::removeMapItemGroup_real(QDeclarativeGeoMapItemGroup *itemGroup)
+{
     if (!itemGroup || itemGroup->quickMap() != this) // cant remove an itemGroup added to another map
-        return;
+        return false;
 
     QPointer<QDeclarativeGeoMapItemGroup> g(itemGroup);
     if (!m_mapItemGroups.removeOne(g))
-        return;
+        return false;
 
     const QList<QQuickItem *> quickKids = itemGroup->childItems();
+    int count = 0;
     for (auto c: quickKids) {
-        QDeclarativeGeoMapItemBase *mapItem = qobject_cast<QDeclarativeGeoMapItemBase *>(c);
-        if (mapItem)
-            removeMapItem(mapItem);
+        count += removeMapChild(c);
     }
     itemGroup->setQuickMap(nullptr);
-    itemGroup->setParentItem(0);
+    if (itemGroup->parentItem() == this)
+        itemGroup->setParentItem(0);
+    return count;
 }
 
 /*!
@@ -2035,14 +2093,23 @@ void QDeclarativeGeoMap::removeMapItemGroup(QDeclarativeGeoMapItemGroup *itemGro
 */
 void QDeclarativeGeoMap::removeMapItemView(QDeclarativeGeoMapItemView *itemView)
 {
+    if (removeMapItemView_real(itemView))
+        emit mapItemsChanged();
+}
+
+bool QDeclarativeGeoMap::removeMapItemView_real(QDeclarativeGeoMapItemView *itemView)
+{
     if (!itemView || itemView->m_map != this) // can't remove a view that is already added to another map
-        return;
+        return false;
 
+    // Leaving this as void since the removal is async (potentially transitioned)
+    // && the delegates *could* be empty mapItemGroups.
     itemView->removeInstantiatedItems();
     itemView->m_map = 0;
     // it can be removed from the list at this point, since no operations that require a Map have to be done
     // anymore on destruction.
     m_mapViews.removeOne(itemView);
+    return removeMapItemGroup_real(itemView); // at this point, delegate instances have been removed.
 }
 
 /*!
@@ -2056,13 +2123,21 @@ void QDeclarativeGeoMap::removeMapItemView(QDeclarativeGeoMapItemView *itemView)
 */
 void QDeclarativeGeoMap::addMapItemView(QDeclarativeGeoMapItemView *itemView)
 {
+    if (addMapItemView_real(itemView))
+        emit mapItemsChanged();
+}
+
+bool QDeclarativeGeoMap::addMapItemView_real(QDeclarativeGeoMapItemView *itemView)
+{
     if (!itemView || itemView->m_map) // can't add a view twice
-        return;
+        return false;
 
+    int count = addMapItemGroup_real(itemView); // at this point, delegates aren't yet incubated.
     // Not appending it to m_mapViews because it seems unnecessary even if the
     // itemView is a child of this (in which case it would be destroyed
     m_mapViews.append(itemView);
     setupMapView(itemView);
+    return count;
 }
 
 /*!
diff --git a/src/location/declarativemaps/qdeclarativegeomap_p.h b/src/location/declarativemaps/qdeclarativegeomap_p.h
index 6948b15b..02379411 100644
--- a/src/location/declarativemaps/qdeclarativegeomap_p.h
+++ b/src/location/declarativemaps/qdeclarativegeomap_p.h
@@ -254,6 +254,16 @@ protected:
     void setError(QGeoServiceProvider::Error error, const QString &errorString);
     void initialize();
     void setZoomLevel(qreal zoomLevel, bool overzoom);
+    bool addMapChild(QObject *child);
+    bool removeMapChild(QObject *child);
+    bool isGroupNested(QDeclarativeGeoMapItemGroup *group);
+
+    bool addMapItem_real(QDeclarativeGeoMapItemBase *item);
+    bool removeMapItem_real(QDeclarativeGeoMapItemBase *item);
+    bool addMapItemGroup_real(QDeclarativeGeoMapItemGroup *itemGroup);
+    bool removeMapItemGroup_real(QDeclarativeGeoMapItemGroup *itemGroup);
+    bool addMapItemView_real(QDeclarativeGeoMapItemView *itemView);
+    bool removeMapItemView_real(QDeclarativeGeoMapItemView *itemView);
 
 private Q_SLOTS:
     void mappingManagerInitialized();
diff --git a/src/location/declarativemaps/qdeclarativegeomapitembase.cpp b/src/location/declarativemaps/qdeclarativegeomapitembase.cpp
index 366992ed..7de6afb5 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitembase.cpp
+++ b/src/location/declarativemaps/qdeclarativegeomapitembase.cpp
@@ -85,10 +85,6 @@ QDeclarativeGeoMapItemBase::QDeclarativeGeoMapItemBase(QQuickItem *parent)
     // Changing opacity on a mapItemGroup should affect also the opacity on the children.
     // This must be notified to plugins, if they are to render the item.
     connect(this, &QQuickItem::opacityChanged, this, &QDeclarativeGeoMapItemBase::mapItemOpacityChanged);
-    parentGroup_ = qobject_cast<QDeclarativeGeoMapItemGroup *>(parent);
-    if (parentGroup_)
-        connect(qobject_cast<QDeclarativeGeoMapItemGroup *>(parent), &QQuickItem::opacityChanged,
-                this, &QDeclarativeGeoMapItemBase::mapItemOpacityChanged);
 }
 
 QDeclarativeGeoMapItemBase::~QDeclarativeGeoMapItemBase()
@@ -285,49 +281,26 @@ QSGNode *QDeclarativeGeoMapItemBase::updateMapItemPaintNode(QSGNode *oldNode, Up
     return 0;
 }
 
+/*!
+    \internal
+
+    The actual combined opacity of the item. Needed by custom renderer to look like
+    the scene-graph one.
+*/
 qreal QDeclarativeGeoMapItemBase::mapItemOpacity() const
 {
     if (parentGroup_)
-        return parentGroup_->opacity() * opacity();
+        return parentGroup_->mapItemOpacity() * opacity();
     return opacity();
 }
 
-bool QDeclarativeGeoMapItemBase::prepareEnterTransition()
-{
-    if (m_transitionManager->m_transitionState == QDeclarativeGeoMapItemTransitionManager::EnterTransition
-            && m_transitionManager->isRunning())
-        return false;
-
-    if (m_transitionManager->m_transitionState != QDeclarativeGeoMapItemTransitionManager::EnterTransition) {
-        setVisible(true);
-        m_transitionManager->m_transitionState = QDeclarativeGeoMapItemTransitionManager::EnterTransition;
-    }
-    return true;
-}
-
-bool QDeclarativeGeoMapItemBase::prepareExitTransition()
+void QDeclarativeGeoMapItemBase::setParentGroup(QDeclarativeGeoMapItemGroup &parentGroup)
 {
-    if (m_transitionManager->m_transitionState == QDeclarativeGeoMapItemTransitionManager::ExitTransition
-            && m_transitionManager->isRunning())
-        return false;
-
-    if (m_transitionManager->m_transitionState != QDeclarativeGeoMapItemTransitionManager::ExitTransition) {
-        m_transitionManager->m_transitionState = QDeclarativeGeoMapItemTransitionManager::ExitTransition;
+    parentGroup_ = &parentGroup;
+    if (parentGroup_) {
+        connect(parentGroup_, &QDeclarativeGeoMapItemGroup::mapItemOpacityChanged,
+                this, &QDeclarativeGeoMapItemBase::mapItemOpacityChanged);
     }
-    return true;
-}
-
-void QDeclarativeGeoMapItemBase::finalizeEnterTransition()
-{
-    m_transitionManager->m_transitionState = QDeclarativeGeoMapItemTransitionManager::NoTransition;
-    emit enterTransitionFinished();
-}
-
-void QDeclarativeGeoMapItemBase::finalizeExitTransition()
-{
-    setVisible(false);
-    m_transitionManager->m_transitionState = QDeclarativeGeoMapItemTransitionManager::NoTransition;
-    emit exitTransitionFinished();
 }
 
 bool QDeclarativeGeoMapItemBase::isPolishScheduled() const
@@ -341,43 +314,4 @@ void QDeclarativeGeoMapItemBase::polishAndUpdate()
     update();
 }
 
-QDeclarativeGeoMapItemTransitionManager::QDeclarativeGeoMapItemTransitionManager(QDeclarativeGeoMapItemBase *mapItem)
-    : QQuickTransitionManager(), m_mapItem(mapItem)
-{
-}
-
-void QDeclarativeGeoMapItemTransitionManager::transitionEnter()
-{
-    if (m_transitionState == ExitTransition)
-        cancel();
-
-    if (!m_mapItem->prepareEnterTransition())
-        return;
-
-    if (m_view && m_view->m_enter)
-        transition(enterActions, m_view->m_enter, m_mapItem);
-    else
-        finished();
-}
-
-void QDeclarativeGeoMapItemTransitionManager::transitionExit()
-{
-    if (!m_mapItem->prepareExitTransition())
-        return;
-
-    if (m_view && m_view->m_exit)
-        transition(exitActions, m_view->m_exit, m_mapItem);
-    else
-        finished();
-}
-
-void QDeclarativeGeoMapItemTransitionManager::finished()
-{
-    if (m_transitionState == EnterTransition)
-        m_mapItem->finalizeEnterTransition();
-    else if (m_transitionState == ExitTransition)
-        m_mapItem->finalizeExitTransition();
-}
-
-
 QT_END_NAMESPACE
diff --git a/src/location/declarativemaps/qdeclarativegeomapitembase_p.h b/src/location/declarativemaps/qdeclarativegeomapitembase_p.h
index 4a2f9282..f884c13e 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitembase_p.h
+++ b/src/location/declarativemaps/qdeclarativegeomapitembase_p.h
@@ -56,12 +56,11 @@
 #include <QtLocation/private/qdeclarativegeomap_p.h>
 #include <QtLocation/private/qlocationglobal_p.h>
 #include <QtLocation/private/qgeomap_p.h>
-#include <QtQuick/private/qquicktransitionmanager_p_p.h>
+#include <QtLocation/private/qdeclarativegeomapitemtransitionmanager_p.h>
 #include <QScopedPointer>
 
 QT_BEGIN_NAMESPACE
-class QDeclarativeGeoMapItemTransitionManager;
-class QDeclarativeGeoMapItemBase;
+
 class Q_LOCATION_PRIVATE_EXPORT QGeoMapViewportChangeEvent
 {
 public:
@@ -80,29 +79,6 @@ public:
     bool rollChanged;
 };
 
-class QDeclarativeGeoMapItemTransitionManager : public QQuickTransitionManager
-{
-public:
-    enum TransitionState {
-        NoTransition, EnterTransition, ExitTransition
-    };
-
-    QDeclarativeGeoMapItemTransitionManager(QDeclarativeGeoMapItemBase *mapItem);
-
-    void transitionEnter();
-    void transitionExit();
-
-protected:
-    void finished() override;
-
-public:
-    QDeclarativeGeoMapItemBase *m_mapItem;
-    QDeclarativeGeoMapItemView *m_view = nullptr;
-    QList<QQuickStateAction> enterActions;
-    QList<QQuickStateAction> exitActions;
-    TransitionState m_transitionState = NoTransition;
-};
-
 class Q_LOCATION_PRIVATE_EXPORT QDeclarativeGeoMapItemBase : public QQuickItem
 {
     Q_OBJECT
@@ -125,15 +101,12 @@ public:
     virtual QGeoMap::ItemType itemType() const = 0;
     qreal mapItemOpacity() const;
 
-    virtual bool prepareEnterTransition();
-    virtual bool prepareExitTransition();
-    virtual void finalizeEnterTransition();
-    virtual void finalizeExitTransition();
+    void setParentGroup(QDeclarativeGeoMapItemGroup &parentGroup);
 
 Q_SIGNALS:
     void mapItemOpacityChanged();
-    Q_REVISION(11) void enterTransitionFinished();
-    Q_REVISION(11) void exitTransitionFinished();
+    Q_REVISION(12) void addTransitionFinished();
+    Q_REVISION(12) void removeTransitionFinished();
 
 protected Q_SLOTS:
     virtual void afterChildrenChanged();
diff --git a/src/location/declarativemaps/qdeclarativegeomapitemgroup.cpp b/src/location/declarativemaps/qdeclarativegeomapitemgroup.cpp
index b4d214ad..a51dcb31 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitemgroup.cpp
+++ b/src/location/declarativemaps/qdeclarativegeomapitemgroup.cpp
@@ -35,6 +35,8 @@
 ****************************************************************************/
 
 #include "qdeclarativegeomapitemgroup_p.h"
+#include "qdeclarativegeomapitembase_p.h"
+#include "qdeclarativegeomap_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -135,9 +137,11 @@ QT_BEGIN_NAMESPACE
     \image api-mapitemgroup.png
 */
 
-QDeclarativeGeoMapItemGroup::QDeclarativeGeoMapItemGroup(QQuickItem *parent): QQuickItem(parent), m_quickMap(nullptr)
+QDeclarativeGeoMapItemGroup::QDeclarativeGeoMapItemGroup(QQuickItem *parent)
+:   QQuickItem(parent), m_quickMap(nullptr)
 {
-
+    connect(this, &QQuickItem::opacityChanged,
+            this, &QDeclarativeGeoMapItemGroup::mapItemOpacityChanged);
 }
 
 QDeclarativeGeoMapItemGroup::~QDeclarativeGeoMapItemGroup()
@@ -145,9 +149,23 @@ QDeclarativeGeoMapItemGroup::~QDeclarativeGeoMapItemGroup()
 
 }
 
+void QDeclarativeGeoMapItemGroup::setParentGroup(QDeclarativeGeoMapItemGroup &parentGroup)
+{
+    m_parentGroup = &parentGroup;
+    connect(m_parentGroup, &QDeclarativeGeoMapItemGroup::mapItemOpacityChanged,
+            this, &QDeclarativeGeoMapItemGroup::mapItemOpacityChanged);
+}
+
 void QDeclarativeGeoMapItemGroup::setQuickMap(QDeclarativeGeoMap *quickMap)
 {
+    if (!quickMap && m_quickMap)
+        m_quickMap->disconnect(this);
     m_quickMap = quickMap;
+    if (m_quickMap) {
+        onMapSizeChanged();
+        connect(m_quickMap, &QQuickItem::widthChanged, this, &QDeclarativeGeoMapItemGroup::onMapSizeChanged);
+        connect(m_quickMap, &QQuickItem::heightChanged, this, &QDeclarativeGeoMapItemGroup::onMapSizeChanged);
+    }
 }
 
 QDeclarativeGeoMap *QDeclarativeGeoMapItemGroup::quickMap() const
@@ -155,4 +173,45 @@ QDeclarativeGeoMap *QDeclarativeGeoMapItemGroup::quickMap() const
     return m_quickMap;
 }
 
+qreal QDeclarativeGeoMapItemGroup::mapItemOpacity() const
+{
+    return ((m_parentGroup) ? m_parentGroup->mapItemOpacity() : 1.0) * opacity();
+}
+
+void QDeclarativeGeoMapItemGroup::classBegin()
+{
+    QQuickItem::classBegin();
+}
+
+void QDeclarativeGeoMapItemGroup::componentComplete()
+{
+    QQuickItem::componentComplete();
+
+    // In certain cases the parent won't be set via the constructor, but rather later on
+    // during the instantiation/incubation process.
+    // Therefore calling setParentGroup here, when the parent is known.
+    // The childrenChanged use case to handle dynamically-added items is currently unsupported.
+    const QList<QQuickItem *> &quickKids = childItems();
+    for (QQuickItem *k : quickKids) {
+        QDeclarativeGeoMapItemGroup *childGroup
+                = qobject_cast<QDeclarativeGeoMapItemGroup *>(k);
+        if (childGroup) {
+            childGroup->setParentGroup(*this);
+            continue;
+        }
+        QDeclarativeGeoMapItemBase *childItem
+                = qobject_cast<QDeclarativeGeoMapItemBase *>(k);
+        if (childItem) {
+            childItem->setParentGroup(*this);
+            continue;
+        }
+    }
+}
+
+void QDeclarativeGeoMapItemGroup::onMapSizeChanged()
+{
+    setWidth(m_quickMap->width());
+    setHeight(m_quickMap->height());
+}
+
 QT_END_NAMESPACE
diff --git a/src/location/declarativemaps/qdeclarativegeomapitemgroup_p.h b/src/location/declarativemaps/qdeclarativegeomapitemgroup_p.h
index f91d291c..395e74a1 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitemgroup_p.h
+++ b/src/location/declarativemaps/qdeclarativegeomapitemgroup_p.h
@@ -49,6 +49,7 @@
 //
 
 #include <QtLocation/private/qlocationglobal_p.h>
+#include <QtLocation/private/qdeclarativegeomapitemtransitionmanager_p.h>
 #include <QtQuick/QQuickItem>
 
 QT_BEGIN_NAMESPACE
@@ -61,10 +62,32 @@ public:
     explicit QDeclarativeGeoMapItemGroup(QQuickItem *parent = 0);
     virtual ~QDeclarativeGeoMapItemGroup();
 
+    void setParentGroup(QDeclarativeGeoMapItemGroup &parentGroup);
     void setQuickMap(QDeclarativeGeoMap *quickMap);
     QDeclarativeGeoMap *quickMap() const;
+
+    qreal mapItemOpacity() const;
+
+Q_SIGNALS:
+    void mapItemOpacityChanged();
+    void addTransitionFinished();
+    void removeTransitionFinished();
+
+protected:
+    // QQmlParserStatus interface
+    void classBegin() override;
+    void componentComplete() override;
+
+protected slots:
+    void onMapSizeChanged();
+
 private:
     QDeclarativeGeoMap *m_quickMap;
+    QDeclarativeGeoMapItemGroup *m_parentGroup = nullptr;
+    QScopedPointer<QDeclarativeGeoMapItemTransitionManager> m_transitionManager;
+
+    friend class QDeclarativeGeoMapItemView;
+    friend class QDeclarativeGeoMapItemTransitionManager;
 };
 
 QT_END_NAMESPACE
diff --git a/src/location/declarativemaps/qdeclarativegeomapitemtransitionmanager.cpp b/src/location/declarativemaps/qdeclarativegeomapitemtransitionmanager.cpp
new file mode 100644
index 00000000..549ab2cb
--- /dev/null
+++ b/src/location/declarativemaps/qdeclarativegeomapitemtransitionmanager.cpp
@@ -0,0 +1,81 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtLocation module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qdeclarativegeomapitemtransitionmanager_p.h"
+#include "qdeclarativegeomapitemview_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QDeclarativeGeoMapItemTransitionManager::QDeclarativeGeoMapItemTransitionManager(QObject *mapItem)
+    : QQuickTransitionManager(), m_mapItem(mapItem)
+{
+}
+
+void QDeclarativeGeoMapItemTransitionManager::transitionEnter()
+{
+    if (m_transitionState == ExitTransition)
+        cancel();
+
+    if (!prepareEnterTransition())
+        return;
+
+    if (m_view && m_view->m_enter)
+        transition(enterActions, m_view->m_enter, m_mapItem);
+    else
+        finished();
+}
+
+void QDeclarativeGeoMapItemTransitionManager::transitionExit()
+{
+    if (!prepareExitTransition())
+        return;
+
+    if (m_view && m_view->m_exit)
+        transition(exitActions, m_view->m_exit, m_mapItem);
+    else
+        finished();
+}
+
+void QDeclarativeGeoMapItemTransitionManager::finished()
+{
+    if (m_transitionState == EnterTransition)
+        finalizeEnterTransition();
+    else if (m_transitionState == ExitTransition)
+        finalizeExitTransition();
+}
+
+
+QT_END_NAMESPACE
diff --git a/src/location/declarativemaps/qdeclarativegeomapitemtransitionmanager_p.h b/src/location/declarativemaps/qdeclarativegeomapitemtransitionmanager_p.h
new file mode 100644
index 00000000..0a83fe39
--- /dev/null
+++ b/src/location/declarativemaps/qdeclarativegeomapitemtransitionmanager_p.h
@@ -0,0 +1,120 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtLocation module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QDECLARATIVEGEOMAPITEMTRANSITIONMANAGER_H
+#define QDECLARATIVEGEOMAPITEMTRANSITIONMANAGER_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtLocation/private/qlocationglobal_p.h>
+#include <QtQuick/QQuickItem>
+#include <QtQuick/private/qquicktransitionmanager_p_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QDeclarativeGeoMapItemView;
+
+class QDeclarativeGeoMapItemTransitionManager : public QQuickTransitionManager
+{
+public:
+    enum TransitionState {
+        NoTransition, EnterTransition, ExitTransition
+    };
+
+    QDeclarativeGeoMapItemTransitionManager(QObject *mapItem);
+
+    void transitionEnter();
+    void transitionExit();
+
+    bool prepareEnterTransition()
+    {
+        if (m_transitionState == QDeclarativeGeoMapItemTransitionManager::EnterTransition
+                && isRunning())
+            return false;
+
+        if (m_transitionState != QDeclarativeGeoMapItemTransitionManager::EnterTransition) {
+    //        setVisible(true);
+            m_transitionState = QDeclarativeGeoMapItemTransitionManager::EnterTransition;
+        }
+        return true;
+    }
+    bool prepareExitTransition()
+    {
+        if (m_transitionState == QDeclarativeGeoMapItemTransitionManager::ExitTransition
+                && isRunning())
+            return false;
+
+        if (m_transitionState != QDeclarativeGeoMapItemTransitionManager::ExitTransition) {
+            m_transitionState = QDeclarativeGeoMapItemTransitionManager::ExitTransition;
+        }
+        return true;
+    }
+    void finalizeEnterTransition()
+    {
+        m_transitionState = QDeclarativeGeoMapItemTransitionManager::NoTransition;
+        // use invokeMethod since this is used on both QDeclarativeGeoMapItemBase and QDeclarativeGeoMapItemGroup
+        QMetaObject::invokeMethod(m_mapItem, QByteArrayLiteral("addTransitionFinished").constData(), Qt::DirectConnection);
+    }
+    void finalizeExitTransition()
+    {
+//        setVisible(false);
+        m_transitionState = QDeclarativeGeoMapItemTransitionManager::NoTransition;
+        QMetaObject::invokeMethod(m_mapItem, QByteArrayLiteral("removeTransitionFinished").constData(), Qt::DirectConnection);
+    }
+
+protected:
+    void finished() override;
+
+public:
+    QObject *m_mapItem;
+    QDeclarativeGeoMapItemView *m_view = nullptr;
+    QList<QQuickStateAction> enterActions;
+    QList<QQuickStateAction> exitActions;
+    TransitionState m_transitionState = NoTransition;
+};
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/location/declarativemaps/qdeclarativegeomapitemview.cpp b/src/location/declarativemaps/qdeclarativegeomapitemview.cpp
index dca92269..415eecb3 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitemview.cpp
+++ b/src/location/declarativemaps/qdeclarativegeomapitemview.cpp
@@ -94,7 +94,7 @@ QT_BEGIN_NAMESPACE
 */
 
 QDeclarativeGeoMapItemView::QDeclarativeGeoMapItemView(QQuickItem *parent)
-    : QObject(parent), m_componentCompleted(false), m_delegate(0),
+    : QDeclarativeGeoMapItemGroup(parent), m_componentCompleted(false), m_delegate(0),
       m_map(0), m_fitViewport(false), m_delegateModel(0)
 {
         m_exit = new QQuickTransition(this);
@@ -116,6 +116,7 @@ QDeclarativeGeoMapItemView::~QDeclarativeGeoMapItemView()
 */
 void QDeclarativeGeoMapItemView::componentComplete()
 {
+    QDeclarativeGeoMapItemGroup::componentComplete();
     m_componentCompleted = true;
     if (!m_itemModel.isNull())
         m_delegateModel->setModel(m_itemModel);
@@ -128,6 +129,7 @@ void QDeclarativeGeoMapItemView::componentComplete()
 
 void QDeclarativeGeoMapItemView::classBegin()
 {
+    QDeclarativeGeoMapItemGroup::classBegin();
     QQmlContext *ctx = qmlContext(this);
     m_delegateModel = new QQmlDelegateModel(ctx, this);
     m_delegateModel->classBegin();
@@ -154,10 +156,15 @@ void QDeclarativeGeoMapItemView::createdItem(int index, QObject */*object*/)
         return;
     // createdItem is emitted on asynchronous creation. In which case, object has to be invoked again.
     // See QQmlDelegateModel::object for further info.
-    QDeclarativeGeoMapItemBase *item =
-            qobject_cast<QDeclarativeGeoMapItemBase *>(m_delegateModel->object(index, QQmlIncubator::Asynchronous));
+
+    if (m_incubationMode == QQmlIncubator::Synchronous) {
+        qWarning() << "createdItem invoked on Synchronous incubation";
+        return;
+    }
+
+    QQuickItem *item = qobject_cast<QQuickItem *>(m_delegateModel->object(index, m_incubationMode));
     if (item)
-        addItemToMap(item, index);
+        addDelegateToMap(item, index);
     else
         qWarning() << "createdItem for " << index << " produced a null item";
 }
@@ -179,16 +186,13 @@ void QDeclarativeGeoMapItemView::modelUpdated(const QQmlChangeSet &changeSet, bo
         for (auto rit = mapRemoves.rbegin(); rit != mapRemoves.rend(); ++rit) {
             const QQmlChangeSet::Change &c = removes.at(rit->second);
             for (int idx = c.end() - 1; idx >= c.start(); --idx)
-                    removeItemFromMap(idx);
+                removeDelegateFromMap(idx);
         }
     }
 
     for (const QQmlChangeSet::Change &c: changeSet.inserts()) {
-        for (int idx = c.start(); idx < c.end(); idx++) {
-            QDeclarativeGeoMapItemBase *item =
-                    qobject_cast<QDeclarativeGeoMapItemBase *>(m_delegateModel->object(idx, QQmlIncubator::Asynchronous));
-            addItemToMap(item, idx); // if not item, a createdItem signal will be emitted.
-        }
+        for (int idx = c.start(); idx < c.end(); idx++)
+            addDelegateToMap(qobject_cast<QQuickItem *>(m_delegateModel->object(idx, m_incubationMode)), idx);
     }
 
     fitViewport();
@@ -290,14 +294,15 @@ void QDeclarativeGeoMapItemView::setMap(QDeclarativeGeoMap *map)
 /*!
     \internal
 */
-void QDeclarativeGeoMapItemView::removeInstantiatedItems()
+void QDeclarativeGeoMapItemView::removeInstantiatedItems(bool transition)
 {
     if (!m_map)
         return;
 
+    // FIXME: removeInstantiatedItems should abort, as well as exit transitions terminated QTBUG-69195
     // Backward as removeItemFromMap modifies m_instantiatedItems
     for (int i = m_instantiatedItems.size() -1; i >= 0 ; i--)
-        removeItemFromMap(i);
+        removeDelegateFromMap(i, transition);
 }
 
 /*!
@@ -312,19 +317,36 @@ void QDeclarativeGeoMapItemView::instantiateAllItems()
         return;
 
     // If here, m_delegateModel may contain data, but QQmlInstanceModel::object for each row hasn't been called yet.
-    for (int i = 0; i < m_delegateModel->count(); i++) {
-        QDeclarativeGeoMapItemBase *item =
-                qobject_cast<QDeclarativeGeoMapItemBase *>(m_delegateModel->object(i, QQmlIncubator::Asynchronous));
-        addItemToMap(item, i); // if not item, createdItem will be emitted.
-    }
+    for (int i = 0; i < m_delegateModel->count(); i++)
+        addDelegateToMap(qobject_cast<QQuickItem *>(m_delegateModel->object(i, m_incubationMode)), i);
 
     fitViewport();
 }
 
-void QDeclarativeGeoMapItemView::removeItemFromMap(int index)
+void QDeclarativeGeoMapItemView::setIncubateDelegates(bool useIncubators)
+{
+    const QQmlIncubator::IncubationMode incubationMode =
+            (useIncubators) ? QQmlIncubator::Asynchronous : QQmlIncubator::Synchronous;
+    if (m_incubationMode == incubationMode)
+        return;
+    m_incubationMode = incubationMode;
+    emit incubateDelegatesChanged();
+}
+
+bool QDeclarativeGeoMapItemView::incubateDelegates() const
+{
+    return m_incubationMode == QQmlIncubator::Asynchronous;
+}
+
+QList<QQuickItem *> QDeclarativeGeoMapItemView::mapItems()
+{
+    return m_instantiatedItems;
+}
+
+void QDeclarativeGeoMapItemView::removeDelegateFromMap(int index, bool transition)
 {
     if (index >= 0 && index < m_instantiatedItems.size()) {
-        QDeclarativeGeoMapItemBase *item = m_instantiatedItems.takeAt(index);
+        QQuickItem *item = m_instantiatedItems.takeAt(index);
         if (!item) {
             if (m_incubatingItems.contains(index)) {
                 // cancel request
@@ -333,50 +355,106 @@ void QDeclarativeGeoMapItemView::removeItemFromMap(int index)
             }
             return;
         }
-        if (m_exit && m_map) {
-            if (!item->m_transitionManager) {
-                QScopedPointer<QDeclarativeGeoMapItemTransitionManager>manager(new QDeclarativeGeoMapItemTransitionManager(item));
-                item->m_transitionManager.swap(manager);
-                item->m_transitionManager->m_view = this;
-            }
-            connect(item, &QDeclarativeGeoMapItemBase::exitTransitionFinished,
-                    this, &QDeclarativeGeoMapItemView::exitTransitionFinished);
-            item->m_transitionManager->transitionExit();
+        // item can be either a QDeclarativeGeoMapItemBase or a QDeclarativeGeoMapItemGroup
+        if (m_exit && m_map &&  transition) {
+            transitionItemOut(item);
         } else {
             disconnect(item, 0, this, 0);
-            if (m_map)
-                m_map->removeMapItem(item);
+            removeDelegateFromMap(item);
+            item->setParentItem(nullptr);   // Needed because
+            item->setParent(nullptr);       // m_delegateModel->release(item) does not destroy the item most of the times!!
             QQmlInstanceModel::ReleaseFlags releaseStatus = m_delegateModel->release(item);
+#ifdef QT_DEBUG
             if (releaseStatus == QQmlInstanceModel::Referenced)
-                qWarning() << "item "<< index << " still referenced";
+                qWarning() << "item "<< index << "(" << item << ") still referenced";
+#else
+            Q_UNUSED(releaseStatus)
+#endif
         }
     }
 }
 
+void QDeclarativeGeoMapItemView::removeDelegateFromMap(QQuickItem *o)
+{
+    if (!m_map)
+        return;
+
+    QDeclarativeGeoMapItemBase *item = qobject_cast<QDeclarativeGeoMapItemBase *>(o);
+    if (item) {
+        m_map->removeMapItem(item);
+        return;
+    }
+    QDeclarativeGeoMapItemView *view = qobject_cast<QDeclarativeGeoMapItemView *>(o);
+    if (view) {
+        m_map->removeMapItemView(view);
+        return;
+    }
+    QDeclarativeGeoMapItemGroup *group = qobject_cast<QDeclarativeGeoMapItemGroup *>(o);
+    if (group) {
+        m_map->removeMapItemGroup(group);
+        return;
+    }
+}
+
+void QDeclarativeGeoMapItemView::transitionItemOut(QQuickItem *o)
+{
+    QDeclarativeGeoMapItemGroup *group = qobject_cast<QDeclarativeGeoMapItemGroup *>(o);
+    if (group) {
+        if (!group->m_transitionManager) {
+            QScopedPointer<QDeclarativeGeoMapItemTransitionManager>manager(new QDeclarativeGeoMapItemTransitionManager(group));
+            group->m_transitionManager.swap(manager);
+            group->m_transitionManager->m_view = this;
+        }
+        connect(group, SIGNAL(removeTransitionFinished()),
+                this, SLOT(exitTransitionFinished()));
+
+        group->m_transitionManager->transitionExit();
+        return;
+    }
+    QDeclarativeGeoMapItemBase *item = qobject_cast<QDeclarativeGeoMapItemBase *>(o);
+    if (item) {
+        if (!item->m_transitionManager) {
+            QScopedPointer<QDeclarativeGeoMapItemTransitionManager> manager(new QDeclarativeGeoMapItemTransitionManager(item));
+            item->m_transitionManager.swap(manager);
+            item->m_transitionManager->m_view = this;
+        }
+        connect(item, SIGNAL(removeTransitionFinished()),
+                this, SLOT(exitTransitionFinished()) );
+
+        item->m_transitionManager->transitionExit();
+        return;
+    }
+}
+
 void QDeclarativeGeoMapItemView::exitTransitionFinished()
 {
-    QDeclarativeGeoMapItemBase *item = static_cast<QDeclarativeGeoMapItemBase *>(sender());
+    QQuickItem *item = qobject_cast<QQuickItem *>(sender());
+    if (!item)
+        return;
     disconnect(item, 0, this, 0);
-    if (m_map)
-        m_map->removeMapItem(item);
+    removeDelegateFromMap(item);
+    item->setParentItem(nullptr);
+    item->setParent(nullptr);
     QQmlInstanceModel::ReleaseFlags releaseStatus = m_delegateModel->release(item);
+#ifdef QT_DEBUG
     if (releaseStatus == QQmlInstanceModel::Referenced)
         qWarning() << "item "<<item<<" still referenced";
+#else
+    Q_UNUSED(releaseStatus)
+#endif
 }
 
 void QDeclarativeGeoMapItemView::addItemToMap(QDeclarativeGeoMapItemBase *item, int index)
 {
-    if (m_map && item && item->quickMap() == m_map) // belonging to another map??
-        return;
 
-    if (m_map) {
-        if (!item) {
-            m_incubatingItems.insert(index);
-            m_instantiatedItems.insert(index, nullptr);
+    if (m_map && item) { // belonging to another map??
+        if (item->quickMap() == m_map)
             return;
-        }
+    }
 
+    if (m_map) {
         insertInstantiatedItem(index, item);
+        item->setParentItem(this);
         m_map->addMapItem(item);
         if (m_enter) {
             if (!item->m_transitionManager) {
@@ -389,7 +467,7 @@ void QDeclarativeGeoMapItemView::addItemToMap(QDeclarativeGeoMapItemBase *item,
     }
 }
 
-void QDeclarativeGeoMapItemView::insertInstantiatedItem(int index, QDeclarativeGeoMapItemBase *o)
+void QDeclarativeGeoMapItemView::insertInstantiatedItem(int index, QQuickItem *o)
 {
     if (m_incubatingItems.contains(index)) {
         m_incubatingItems.remove(index);
@@ -399,6 +477,70 @@ void QDeclarativeGeoMapItemView::insertInstantiatedItem(int index, QDeclarativeG
     }
 }
 
+void QDeclarativeGeoMapItemView::addItemViewToMap(QDeclarativeGeoMapItemView *item, int index)
+{
+    if (!item || (m_map && item->quickMap() == m_map))
+        return;
+
+    if (m_map) {
+        insertInstantiatedItem(index, item);
+        item->setParentItem(this);
+        m_map->addMapItemView(item);
+        if (m_enter) {
+            if (!item->m_transitionManager) {
+                QScopedPointer<QDeclarativeGeoMapItemTransitionManager> manager(new QDeclarativeGeoMapItemTransitionManager(item));
+                item->m_transitionManager.swap(manager);
+            }
+            item->m_transitionManager->m_view = this;
+            item->m_transitionManager->transitionEnter();
+        }
+    }
+}
+
+void QDeclarativeGeoMapItemView::addItemGroupToMap(QDeclarativeGeoMapItemGroup *item, int index)
+{
+    if (!item || (m_map && item->quickMap() == m_map))
+        return;
+
+    if (m_map) {
+        insertInstantiatedItem(index, item);
+        item->setParentItem(this);
+        m_map->addMapItemGroup(item);
+        if (m_enter) {
+            if (!item->m_transitionManager) {
+                QScopedPointer<QDeclarativeGeoMapItemTransitionManager>manager(new QDeclarativeGeoMapItemTransitionManager(item));
+                item->m_transitionManager.swap(manager);
+            }
+            item->m_transitionManager->m_view = this;
+            item->m_transitionManager->transitionEnter();
+        }
+    }
+}
+
+void QDeclarativeGeoMapItemView::addDelegateToMap(QQuickItem *object, int index)
+{
+    if (!object) {
+        m_incubatingItems.insert(index);
+        m_instantiatedItems.insert(index, nullptr);
+        return;
+    }
+    QDeclarativeGeoMapItemBase *item = qobject_cast<QDeclarativeGeoMapItemBase *>(object);
+    if (item) { // else createdItem will be emitted.
+        addItemToMap(item, index);
+        return;
+    }
+    QDeclarativeGeoMapItemView *view = qobject_cast<QDeclarativeGeoMapItemView *>(object);
+    if (view) {
+        addItemViewToMap(view, index);
+        return;
+    }
+    QDeclarativeGeoMapItemGroup *group = qobject_cast<QDeclarativeGeoMapItemGroup *>(object);
+    if (group) {
+        addItemGroupToMap(group, index);
+        return;
+    }
+}
+
 QT_END_NAMESPACE
 
 
diff --git a/src/location/declarativemaps/qdeclarativegeomapitemview_p.h b/src/location/declarativemaps/qdeclarativegeomapitemview_p.h
index 9e1bebad..58ef2835 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitemview_p.h
+++ b/src/location/declarativemaps/qdeclarativegeomapitemview_p.h
@@ -58,6 +58,7 @@
 #include <QtQml/qqml.h>
 #include <QtQml/private/qqmldelegatemodel_p.h>
 #include <QtQuick/private/qquicktransition_p.h>
+#include <QtLocation/private/qdeclarativegeomapitemgroup_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -71,18 +72,19 @@ class QQmlOpenMetaObjectType;
 class MapItemViewDelegateIncubator;
 class QDeclarativeGeoMapItemViewItemData;
 class QDeclarativeGeoMapItemView;
+class QDeclarativeGeoMapItemGroup;
 
-class Q_LOCATION_PRIVATE_EXPORT QDeclarativeGeoMapItemView : public QObject, public QQmlParserStatus
+class Q_LOCATION_PRIVATE_EXPORT QDeclarativeGeoMapItemView : public QDeclarativeGeoMapItemGroup
 {
     Q_OBJECT
 
-    Q_INTERFACES(QQmlParserStatus)
-
     Q_PROPERTY(QVariant model READ model WRITE setModel NOTIFY modelChanged)
     Q_PROPERTY(QQmlComponent *delegate READ delegate WRITE setDelegate NOTIFY delegateChanged)
     Q_PROPERTY(bool autoFitViewport READ autoFitViewport WRITE setAutoFitViewport NOTIFY autoFitViewportChanged)
     Q_PROPERTY(QQuickTransition *add MEMBER m_enter REVISION 12)
     Q_PROPERTY(QQuickTransition *remove MEMBER m_exit REVISION 12)
+    Q_PROPERTY(QList<QQuickItem *> mapItems READ mapItems REVISION 12)
+    Q_PROPERTY(bool incubateDelegates READ incubateDelegates WRITE setIncubateDelegates NOTIFY incubateDelegatesChanged REVISION 12)
 
 public:
     explicit QDeclarativeGeoMapItemView(QQuickItem *parent = 0);
@@ -98,9 +100,14 @@ public:
     void setAutoFitViewport(const bool &fit);
 
     void setMap(QDeclarativeGeoMap *);
-    void removeInstantiatedItems();
+    void removeInstantiatedItems(bool transition = true);
     void instantiateAllItems();
 
+    void setIncubateDelegates(bool useIncubators);
+    bool incubateDelegates() const;
+
+    QList<QQuickItem *> mapItems();
+
     // From QQmlParserStatus
     void componentComplete() override;
     void classBegin() override;
@@ -109,6 +116,7 @@ Q_SIGNALS:
     void modelChanged();
     void delegateChanged();
     void autoFitViewportChanged();
+    void incubateDelegatesChanged();
 
 private Q_SLOTS:
     void destroyingItem(QObject *object);
@@ -119,15 +127,22 @@ private Q_SLOTS:
 
 private:
     void fitViewport();
-    void removeItemFromMap(int index);
+    void removeDelegateFromMap(int index, bool transition = true);
+    void removeDelegateFromMap(QQuickItem *o);
+    void transitionItemOut(QQuickItem *o);
+
+    void insertInstantiatedItem(int index, QQuickItem *o);
     void addItemToMap(QDeclarativeGeoMapItemBase *item, int index);
-    void insertInstantiatedItem(int index, QDeclarativeGeoMapItemBase *o);
+    void addItemViewToMap(QDeclarativeGeoMapItemView *item, int index);
+    void addItemGroupToMap(QDeclarativeGeoMapItemGroup *item, int index);
+    void addDelegateToMap(QQuickItem *object, int index);
 
     bool m_componentCompleted;
+    QQmlIncubator::IncubationMode m_incubationMode = QQmlIncubator::Asynchronous;
     QQmlComponent *m_delegate;
     QVariant m_itemModel;
     QDeclarativeGeoMap *m_map;
-    QList<QDeclarativeGeoMapItemBase *> m_instantiatedItems;
+    QList<QQuickItem *> m_instantiatedItems;
     QSet<int> m_incubatingItems;
     bool m_fitViewport;
     QQmlDelegateModel *m_delegateModel;
diff --git a/tests/auto/declarative_ui/tst_map_itemview.qml b/tests/auto/declarative_ui/tst_map_itemview.qml
index 097212ca..0ab9d494 100644
--- a/tests/auto/declarative_ui/tst_map_itemview.qml
+++ b/tests/auto/declarative_ui/tst_map_itemview.qml
@@ -28,7 +28,7 @@
 
 import QtQuick 2.0
 import QtTest 1.0
-import QtLocation 5.6
+import QtLocation 5.12
 import QtPositioning 5.5
 import QtLocation.Test 5.5
 
@@ -49,6 +49,7 @@ Item {
     MapItemView {
         id: routeItemViewExtra
         model: routeModel
+        incubateDelegates: false
         delegate: Component {
             MapRoute {
                 route:  routeData
@@ -58,6 +59,10 @@ Item {
 
     MapItemView {
         id: listModelItemViewExtra
+        objectName: "listModelItemViewExtra"
+        incubateDelegates: false
+        add: null
+        remove: null
         model: ListModel {
             id: testingListModelExtra
             ListElement { lat: 11; lon: 31 }
@@ -252,6 +257,9 @@ Item {
 
         MapItemView {
             id: listModelItemView
+            incubateDelegates: false
+            add: null
+            remove: null
             model: ListModel {
                 id: testingListModel
                 ListElement { lat: 11; lon: 31 }
@@ -487,7 +495,7 @@ Item {
             testingListModelExtra.clear()
             tryCompare(mapForTestingListModel, "mapItemsLength", 0)
             mapForTestingListModel.removeMapItemView(listModelItemViewExtra)
-
+            tryCompare(mapForTestingListModel, "mapItemsLength", 0)
             mapForTestingListModel.addMapItemView(listModelItemView)
             tryCompare(mapForTestingListModel, "mapItemsLength", 3)