[Solved] QListview - alter font of one line dynamically

Moschops

I have a QListView, happily showing the contents of a model. The user can select items, and onDoubleClick() makes things happen. It would be nice if the user had some extant way of knowing what they had double-clicked last given that they can change the selection with single-click after having done so, and an obvious way to do this is to make whatever line was last double-clicked bold.

How can I do this? Am I going to have to subclass QListView and make my own paint function or some such?

raven-worx

You would have to do the drawing of the text yourself in a delegate subclass.
Try this and check if it fits your needs:
@
void MyDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
//draw background and selection-highlighting
#if QT_VERSION < 0x050000
QStyleOptionViewItemV4 opt(*qstyleoption_cast<const QStyleOptionViewItemV4 *>(&option));
#else
QStyleOptionViewItem opt = option;
#endif

this->initStyleOption(&opt, index);
QString text = opt.text;
opt.text = "";
const QWidget *widget = opt.widget;
QStyle *style = widget ? widget->style() : QApplication::style();
style->drawControl(QStyle::CE_ItemViewItem, &opt, painter, widget);

QFont font = opt.font;
if( ... )   //your condition to decide if you want to draw bold text or not
    font.setBold(true);

painter->save();
    painter->setRenderHints(QPainter::TextAntialiasing);
    painter->setFont(font);
    painter->drawText( option.rect, text );
painter->restore();

}
@
Not tested though.

Moschops

Turned out my first approach there was massive overkill. In the end, it was simple:

@QVariant subclassedModel::data(const QModelIndex& index, int role) const
{
...

if (role == Qt::FontRole)
{

    if (condition_on_model_item_to_need_to_be_in_bold_font)
    {
        QFont boldFont;
        boldFont.setBold(true);
        return boldFont;
    }
   
}@