set parent when creating a QML component from C++

[lqsa]

Hello,

I've a QML component that is created from C++ code:

QML Code:

Rectangle {
        width: parent.width
        y: parent.height / 2
        color: "red"
    }

C++ Code:

    QQmlComponent component(engine, QUrl(src));
    QObject *comp = component.create();
    QQuickItem *item = qobject_cast<QQuickItem*>(comp);
    item->setParentItem(root);

When the component is created appears these errors:

TypeError: Cannot read property 'height' of null
TypeError: Cannot read property 'width' of null

On creation, the parent property is null and not is valid until the item->setParentItem is executed. How can I set the parent item when creating the component? or how to avoid these errors?

Best regards.

[bogong]

There are object cast need to be done for "root" object too

QQmlComponent component(engine, QUrl(src));
    QObject *comp = component.create();
    QQuickItem *item = qobject_cast<QQuickItem*>(comp);
    item->setParentItem(qobject_cast<QQuickItem*>(root));

This works for me in my project:

// QtQuick Application
int main(int Counter, char *Arguments[]) {

	QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
	QGuiApplication Application(Counter, Arguments);

	QQmlApplicationEngine Engine;
	Engine.load(QUrl(Main));
	if (Engine.rootObjects().isEmpty()) {
		return -1;
	}

	QObject *oRootObject = dynamic_cast<QObject*>(Engine.rootObjects()[0]);
	QObject *oBottomBlock = oRootObject->findChild<QObject*>("bottomBlock");

	if (oBottomBlock) {

		QQmlComponent oComponent(&Engine,QUrl(QString("qrc:/ButtonExit.qml")));
		QObject *oButtonExit = oComponent.create();
		QQuickItem *oItemButtonExit = qobject_cast<QQuickItem*>(oButtonExit);
		oItemButtonExit->setParentItem(qobject_cast<QQuickItem*>(oBottomBlock));
	}

	return Application.exec();
}