PopupPresenter.qml

import QtQuick 2.10
import QtQuick.Controls 2.3

QtObject {
    id: _popPresenter

    property Item rootItem: null

    property var _popups: []

    function presentPopup(popup) {
        popup.parent = rootItem;
        popup.closed.connect(function() {
            var index = _popups.indexOf(popup);
            if(index > -1) {
                popup.destroy();
                _popups.splice(index, 1);
            }
        });
        _popups.push(popup);
        popup.open();
        return true;
    }

    function closeAction() {
        if(_popups.length > 0) {
            _popups[_popups.length - 1].close();
            return true;
        } else
            return false;
    }
}