Can't visibly instantiate at runtime via QQmlComponent - c++

Question

I am kidding around with a quite simple QML sample that should end up being some kind of chessboard, but for some reason I can't properly add cells at runtime. A cell is defined using a C++ Class (BasicCell which extends QQuickItem) and can be styled using Qml (cell.qml):
BasicCell {
width: 32
height: 32
Rectangle {
anchors.fill : parent
color : "green"
}
}
I use QQmlComponent to construct instances of this "styled" BasicCell at runtime:
QQmlComponent cellComponent(qmlEngine(), cellUrl, this);
// Make sure we could actually load that QML component
if (cellComponent.status() != QQmlComponent::Ready)
{
std::cerr << "Error loading cell.qml:" << std::endl;
for (const auto& err : cellComponent.errors())
{
std::cerr << " " << err.toString().toStdString() << std::endl;
}
}
for (int x = 0; x < mNumTiles.width(); ++x)
{
for (int y = 0; y < mNumTiles.height(); y++)
{
BasicCell* cell = qobject_cast<BasicCell*>(cellComponent.create());
cell->setParent(this);
cell->setSize(QSize(tileSize(), tileSize()));
cell->setGridPos(QPoint(x, y));
childItems().append(cell);
mCells.insert(cell->gridPos(), cell);
}
}
When using the QML Debugger I can see that I have ended up with the "correct" hierarchy:
Game
BasicCell
Rectangle
BasicCell
Rectangle
...
But I can't see a thing ... I double and triple checked: All of those rectangles and basic cells do have the appropriate sizes set.
Getting more and more frustrated, I finally copied the code from the cell.qml and pasted it as a direct child into the Board.qml. To my astonishment, this renders the cell exactly as I would have expected it.
What am I missing in my use of QQmlComponent that differs from this kind of instantionation in QML?
Game
{
// Should be created at runtime using QQmlComponent
BasicCell {
width: 32
height: 32
Rectangle {
anchors.fill: parent
color : "green"
}
gridPos: "0,0"
}
}

Answer 1

cell->setParent(this);
should be
cell->setParentItem(this);
The concept of the visual parent differs from that of the QObject
parent. An item's visual parent may not necessarily be the same as its
object parent. See Concepts - Visual Parent in Qt Quick for more
details.
That was taken from:
http://qt-project.org/doc/qt-5/qquickitem.html#parent-prop