Question

I am implementing QAbstractTableModel and I would like to insert a QPushButton in the last column of each row. When users click on this button, a new window is shown with more information about this row.

Do you have any idea how to insert the button? I know about delegating system but all examples are only about “how to edit color with the combo box”…

Answer 1

The model-view architecture isn’t made to insert widgets into different cells, but you can draw the push button within the cell.

The differences are:

1. It will only be a drawing of a pushbutton
2. Without extra work (perhaps quite a bit of extra work) the button won’t be highlighted on mouseover
3. In consequence of #1 above, you can’t use signals and slots

That said, here’s how to do it:

Subclass QAbstractItemDelegate (or QStyledItemDelegate) and implement the paint() method. To draw the pushbutton control (or any other control for that matter) you’ll need to use a style or the QStylePainter::drawControl() method:

class PushButtonDelegate : public QAbstractItemDelegate
{
    // TODO: handle public, private, etc.
    QAbstractItemView *view;

    public PushButtonDelegate(QAbstractItemView* view)
    {
        this->view = view;
    }

    void PushButtonDelegate::paint(
        QPainter* painter,
        const QStyleOptionViewItem & option,
        const QModelIndex & index
        ) const 
    {
        // assuming this delegate is only registered for the correct column/row
        QStylePainter stylePainter(view);
        // OR: stylePainter(painter->device)

        stylePainter->drawControl(QStyle::CE_PushButton, option);
        // OR: view->style()->drawControl(QStyle::CE_PushButton, option, painter, view);
        // OR: QApplication::style()->drawControl(/* params as above */);
    }
}

Since the delegate keeps you within the model-view realm, use the views signals about selection and edits to popup your information window.