Extend QParameterizableObject to accept any QObject as quick child

In this way, not only map parameters can be nested, but also
QGeoMapObjects themselves, allowing to avoid one long standing
limitation present in map items, where nested items have never
been supported.

Change-Id: I90ec7a6aeb1d91a38182258b422b8c60bcc9616e
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

2 files changed, 46 insertions, 29 deletions

diff --git a/src/location/declarativemaps/qparameterizableobject.cpp b/src/location/declarativemaps/qparameterizableobject.cpp
index a95f290e..0e138b86 100644
--- a/src/location/declarativemaps/qparameterizableobject.cpp
+++ b/src/location/declarativemaps/qparameterizableobject.cpp
@@ -44,41 +44,45 @@ QParameterizableObject::QParameterizableObject(QObject *parent)
     : QObject(parent)
 {}
 
-QQmlListProperty<QDeclarativeGeoMapParameter> QParameterizableObject::declarativeParameters()
+void QParameterizableObject::appendChild(QObject *v)
 {
-    return QQmlListProperty<QDeclarativeGeoMapParameter>(this, nullptr,
-                                                         &QParameterizableObject::append,
-                                                         &QParameterizableObject::count,
-                                                         &QParameterizableObject::at,
-                                                         &QParameterizableObject::clear);
+    m_children.append(v);
 }
 
-QList<QGeoMapParameter*> QParameterizableObject::parameters() const
+void QParameterizableObject::clearChildren()
 {
-    QList<QGeoMapParameter*> params;
-    for (auto param : qAsConst(m_parameters))
-        params << param;
-    return params;
+    m_children.clear();
 }
 
-void QParameterizableObject::append(QQmlListProperty<QDeclarativeGeoMapParameter> *p, QDeclarativeGeoMapParameter *v)
+QQmlListProperty<QObject> QParameterizableObject::declarativeChildren()
 {
-    static_cast<QParameterizableObject*>(p->object)->m_parameters.append(v);
+    return QQmlListProperty<QObject>(this, nullptr,
+                                                   &QParameterizableObject::append,
+                                                   &QParameterizableObject::count,
+                                                   &QParameterizableObject::at,
+                                                   &QParameterizableObject::clear);
 }
 
-int QParameterizableObject::count(QQmlListProperty<QDeclarativeGeoMapParameter> *p)
+void QParameterizableObject::append(QQmlListProperty<QObject> *p, QObject *v)
 {
-    return static_cast<QParameterizableObject*>(p->object)->m_parameters.count();
+    QParameterizableObject *object = static_cast<QParameterizableObject*>(p->object);
+    object->appendChild(v);
 }
 
-QDeclarativeGeoMapParameter *QParameterizableObject::at(QQmlListProperty<QDeclarativeGeoMapParameter> *p, int idx)
+int QParameterizableObject::count(QQmlListProperty<QObject> *p)
 {
-    return static_cast<QParameterizableObject*>(p->object)->m_parameters.at(idx);
+    return static_cast<QParameterizableObject*>(p->object)->m_children.count();
 }
 
-void QParameterizableObject::clear(QQmlListProperty<QDeclarativeGeoMapParameter> *p)
+QObject *QParameterizableObject::at(QQmlListProperty<QObject> *p, int idx)
 {
-    static_cast<QParameterizableObject*>(p->object)->m_parameters.clear();
+    return static_cast<QParameterizableObject*>(p->object)->m_children.at(idx);
+}
+
+void QParameterizableObject::clear(QQmlListProperty<QObject> *p)
+{
+    QParameterizableObject *object = static_cast<QParameterizableObject*>(p->object);
+    object->clearChildren();
 }
 
 QT_END_NAMESPACE
diff --git a/src/location/declarativemaps/qparameterizableobject_p.h b/src/location/declarativemaps/qparameterizableobject_p.h
index c6118c93..e450c6ec 100644
--- a/src/location/declarativemaps/qparameterizableobject_p.h
+++ b/src/location/declarativemaps/qparameterizableobject_p.h
@@ -54,26 +54,39 @@
 #include <QQmlParserStatus>
 
 QT_BEGIN_NAMESPACE
-class QDeclarativeGeoMapParameter;
 class QGeoMapParameter;
 class Q_LOCATION_PRIVATE_EXPORT QParameterizableObject : public QObject
 {
     Q_OBJECT
-    Q_PROPERTY(QQmlListProperty<QDeclarativeGeoMapParameter> parameters READ declarativeParameters DESIGNABLE false)
-    Q_CLASSINFO("DefaultProperty", "parameters")
+    Q_PROPERTY(QQmlListProperty<QObject> quickChildren READ declarativeChildren DESIGNABLE false)
+    Q_CLASSINFO("DefaultProperty", "quickChildren")
 
 public:
     explicit QParameterizableObject(QObject *parent = nullptr);
-    QList<QGeoMapParameter *> parameters() const;
+
+    template <typename T = QObject>
+    QList<T*> quickChildren() const
+    {
+        QList<T*> res;
+        for (auto kid : qAsConst(m_children)) {
+            auto val = qobject_cast<T*>(kid);
+            if (val)
+                res.push_back(val);
+        }
+        return res;
+    }
 
 protected:
-    static void append(QQmlListProperty<QDeclarativeGeoMapParameter> *p, QDeclarativeGeoMapParameter *v);
-    static int count(QQmlListProperty<QDeclarativeGeoMapParameter> *p);
-    static QDeclarativeGeoMapParameter *at(QQmlListProperty<QDeclarativeGeoMapParameter> *p, int idx);
-    static void clear(QQmlListProperty<QDeclarativeGeoMapParameter> *p);
+    virtual void appendChild(QObject *v);
+    virtual void clearChildren();
+
+    static void append(QQmlListProperty<QObject> *p, QObject *v);
+    static int count(QQmlListProperty<QObject> *p);
+    static QObject *at(QQmlListProperty<QObject> *p, int idx);
+    static void clear(QQmlListProperty<QObject> *p);
 
-    QQmlListProperty<QDeclarativeGeoMapParameter> declarativeParameters();
-    QList<QDeclarativeGeoMapParameter*> m_parameters;
+    QQmlListProperty<QObject> declarativeChildren();
+    QList<QObject*> m_children;
 };
 QT_END_NAMESPACE