[solved] QObject::findChild() not working for QML Items inside Window

  • Hello,

    I need to get a pointer to one of my QML elements from my C++ code, which should be possible with findChild() (see http://doc.qt.io/qt-5/qtqml-cppintegration-interactqmlfromcpp.html)

    However, it just doesn't work. When I get the top-level item from window->contentItem() and call findChild(), it keeps returning zero pointer.

    My main.cpp:

    #include <QGuiApplication>
    #include <QQuickWindow>
    #include <QQuickItem>
    #include <QtQml>
    #include <QTimer>
    #include <QtDebug>
    void checkItem(QQmlApplicationEngine *pEngine);
    int main(int argc, char *argv[])
        QGuiApplication app(argc, argv);
        QQmlApplicationEngine engine;
        QTimer::singleShot(2000, [&]() {
        return app.exec();
    void checkItem(QQmlApplicationEngine *pEngine) {
        QQuickWindow *window = qobject_cast<QQuickWindow *>(pEngine->rootObjects().first());
        QQuickItem *topItem = window->contentItem();
        qDebug() << "topItem: " << topItem;
        QQuickItem *rect = topItem->findChild<QQuickItem *>("myItem");
        qDebug() << "rect: " << rect;

    My main.qml:

    import QtQuick 2.5
    import QtQuick.Window 2.2
    Window {
        visible: true
        Rectangle {
            width: 100
            height: 100
            color: "lightblue"
            objectName: "myItem"
            Text {
                text: qsTr("Hello world!")
                anchors.centerIn: parent

    Output of the program:

    topItem:  QQuickRootItem(0x1e929b0, parent=0x0, geometry=0,0 160x160)
    rect:  QQuickItem(0)

    Of course I also tested whether topItem isn't the rectangle itself, but topItem->objectName() prints just empty string.
    Any ideas?

  • I got it working by not searching among children of topItem, but of window:

    QQuickItem *rect = window->findChild<QQuickItem *>("myItem");

    I find it astonishing, because window->contentItem() should return the root item of the scene. So my light blue rectangle should definitely be one of its children.

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.