QTableView / QItemDelegate customize selection

Toby

Hi everyone

because the user must be able to see the row's background-color i want to replace the default row-selection-style with a 1px frame at the rows/cells borders.
That's why i subclassed QItemDelegate and implemented my own paint-Method.

void QSelectionItemDelegate::paint( QPainter *painter_, const QStyleOptionViewItem &option_, const QModelIndex &index_ ) const
{
    QStyleOptionViewItem opt = option_;
    this->QItemDelegate::paint( painter_, opt, index_ );
    if ( option_.state & QStyle::State_Selected )
    {
        painter_->setPen( Qt::red );
        painter_->drawRect( option_.rect );
    }
}

Drawing the red frame works perfectly, but the default row-selection-style ( blue filled rect ) is visible as well. How can i get rid of the default selection-style and only draw my red frame?

greetings Toby

Christian Ehrlicher

Remove the selected state before calling paint base method.

And please use QStyledItemDelegate - QItemDelegate is deprecated.

Toby

Works perfectly. Many thanks!


void QSelectionItemDelegate::paint( QPainter *painter_, const QStyleOptionViewItem &option_, const QModelIndex &index_ ) const
{
    // copying QStyleOptionViewItem for modification
    QStyleOptionViewItem opt = option_;
    // remove selected-flag
    if ( opt.state & QStyle::State_Selected )
        opt.state &= ~QStyle::State_Selected;
    
    // call base for normal painting
    QStyledItemDelegate::paint( painter_, opt, index_ );

    // grab original selected_state and draw selection-frame
    if ( option_.state & QStyle::State_Selected )
    {
        QRect r( opt.rect.left(), opt.rect.top(), opt.rect.width() - 1, opt.rect.height() - 1 );
        painter_->setPen( Qt::red );
        painter_->drawRect( r );
    }
}

Christian Ehrlicher

@Toby said in QTableView / QItemDelegate customize selection:

painter_->setPen( Qt::red );

Even it's not applicable here you should use QPainter::Save()/restore() when you change the painter's state inside such functions to avoid spurious paintings when the painter is used afterwards.

Toby

Thanks for the advice. :-)
Last Question: is there a (good) way to find out whether the row above or below is also in selected_state ?

Christian Ehrlicher

@Toby said in QTableView / QItemDelegate customize selection:

is there a (good) way to find out whether the row above or below is also in selected_state ?

No, not with QStyleOptionViewItem. You need access to the selection model somehow.

Toby

ok, thx.