Question

I’ve never done any item delegates in Qt before, and I think the documentation doesn’t explain well about more complex delegates.

I need to create 2 styles of Symbian(^3) style lists

Type 1:

This is for common navigation lists, the icon and the lower label are optional.

Type 2:

This is for settings lists, where the pushbutton can be a toggle(on/off)-button or execute a context menu, etc.

How would I go on creating these sort of item delegates?

Best Regards,
Rat

Answer 1

I had to make something similar once. This is how I did it.

My delegate class declaration. As you can see it has a member: QLabel *label. You can add another label or a pushbutton, depending on your needs.

class MyItemDelegate : public QStyledItemDelegate
{
public:
    explicit MyItemDelegate(QObject *parent = 0);
    ~MyItemDelegate();
protected:
    void paint(QPainter *painter,
               const QStyleOptionViewItem &option, const QModelIndex &index) const;
    QSize sizeHint(const QStyleOptionViewItem &option,
                   const QModelIndex &index) const;
private:
    QLabel *label;
};

My paint() and sizeHint() methods.

QSize MyItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.isValid())
        return QSize();
    QVariant data = index.data(Qt::DisplayRole);

    label->setText(data.toString());
    label->resize(label->sizeHint());
    QSize size(option.rect.width(), label->height());
    return size;
}

void MyItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.isValid())
        return;
    QVariant data = index.data(Qt::DisplayRole);

    // Not necessary to do it here, as it's been already done in sizeHint(), but anyway.
    label->setText(data.toString());

    painter->save();

    QRect rect = option.rect;

    // This will draw a label for you. You can draw a pushbutton the same way.
    label->render(painter, QPoint(rect.topLeft().x(), rect.center().y() - label->height() / 2),
                  QRegion(label->rect()), QWidget::RenderFlags());

    painter->restore();
}

Hope this is what you’ve been looking for. Good luck!