paintEvent in QTableView derived class: Paint device returned engine == 0, type: 1

Question

As a follow up of Qt load indicator by animated image (aka preloader) or alternative? I try to paint inside a QTableView. But when I initialize the QPaint

Answer 1

As QTableView is a subclass of QAbstractScrollArea you should open QPainter on its viewport:

void CDerivedFromQTableView::paintEvent(QPaintEvent *event)
{
    QTableView::paintEvent(event); // draw original content

    QPainter p(this->viewport());
    p.drawRect(0, 0, 20, 20);
}

The docs say it:

This event handler can be reimplemented in a subclass to receive paint events (passed in event), for the viewport() widget.

Note: If you open a painter, make sure to open it on the viewport().