QML findChild ListModel not found when instantiated in Window

hvoigt

Hi,

I just discovered that when you instantiate a ListModel inside Window you can not find it via findChild from the root object. If you put it inside something else it can be found.

Example code:

main.cpp:

#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

    QList<QObject *> roots = engine.rootObjects();
    if (roots.count() < 1)
        qFatal("Error: No root QML Object found, closing Application");

    qDebug("root count: %i", roots.count());

    QObject *model = roots[0]->findChild<QObject*>("myModel");
    if (!model)
        qCritical("myModel not found");

    return app.exec();
}

main.qml:

import QtQuick 2.3
import QtQuick.Window 2.2

Window {
    id: window
    visible: true
    width: 640
    height: 480

    ListModel {
        id: myModel
        objectName: "myModel"
        ListElement {
            name: "first"
        }
        ListElement {
            name: "second"
        }
    }

    Column {
        anchors.fill: parent
        Repeater {
            model: myModel
            delegate: Rectangle {
                width: window.width
                height: 15
                color: "blue"

                Text {
                    id: text
                    anchors.fill: parent
                    text: name
                }
            }
        }
    }
}

With this code myModel is not found, but when I move it into e.g. Column findChild() finds it.

Is this a bug?

jpnurmi

Is this a bug?

Yes, I think this could be fairly well considered as a bug. It should be easy to fix by setting QQuickWindow as a QObject-parent of QQuickRootItem in http://code.qt.io/cgit/qt/qtdeclarative.git/tree/src/quick/items/qquickwindow.cpp#n520. Not 100% sure if it has any undesired side-effects, though.

hvoigt

Solution: Filed this as a bugreport here: https://bugreports.qt.io/browse/QTBUG-55592