findChild always returns NULL looking for QML objects

poncho524

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

I have a QQuickWindow, created a QQmlComponent and setParentItem(window->contentItem)

I'm trying to find one of the QQuickItem's now existing in that window, but
window->findChild<QQuickItem*> returns nothing

neither does
window->contentItem->findChild

What gives? I'm trying to find it by its objectName... this should work, no?

poncho524

Ok, here's the screwy behavior i found

QQmlEngine engine;

QQmlComponent formWindowComp(&engine, QUrl("qrc:/formWindow.qml"));
QQuickWindow *formWindow=qobject_cast<QQuickWindow*>(formWindowComp.create());

QQmlComponent menuComp(engine, QUrl("qrc:/testqml.qml"));
QQuickItem *menu=qobject_cast<QQuickItem*>(menuComp.create());
menu->setParentItem(formWindow->contentItem());

all works find here... i get testqml.qml showing up in my formwindow.qml.

Now when i want to find an element inside of testqml.qml, you'd think i could do

QObject *thing=formWindow->findChild<QObject*>("thing");

but this always returns NULL

This is what works tho...

QObject *thing;
auto list=formWindow->contentItem->childItems();
for (auto i : list) {
  thing=i->findChild<QObject*>("thing");
  if (thing) break;
}

So why doesn't "thing" exist as a child of formWindow? or why doesn't it exist as a child of formwindow->contentItem?

Why do i have to get the children of contentItem before i can successfully search?

stevemcgf

parent and parentItem are different concepts parentItem defines the "visual" parent and parent defines the QObject parent.

To get the visual childs you should use childItems.

Take a look at this link
http://doc.qt.io/qt-5/qtquick-visualcanvas-visualparent.html

zilti

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