#include <QtCore/qtimer.h>
#include <QtGui/qguiapplication.h>
#include <QtQml/qqmlengine.h>
#include <QtQuick/qquickview.h>
#include <QtQuick/qquickitem.h>

int main(int argc, char ** argv)
{
    const QByteArray qml =
            "import QtQuick 2.3\n"
            "TextEdit {\n"
            "    text: 'Switch Delegate'\n"
            "}";

    QGuiApplication app(argc, argv);

    QQmlEngine engine;

    QQmlComponent component(&engine);
    component.setData(qml, QUrl());

    QQuickItem *contentItem = qobject_cast<QQuickItem *>(component.create());
    QQuickView window(&engine, nullptr);
    window.setContent(QUrl(), &component, contentItem);
    window.show();

    QTimer::singleShot(100, [&](){
        // window.close() here and it works
        for (QQuickItem *oldItem : window.contentItem()->childItems())
            delete oldItem;
        window.close();

        QQuickItem *item = qobject_cast<QQuickItem *>(component.create());
        item->setParentItem(window.contentItem());
        window.setVisible(true);
    });

    return app.exec();
}