bookdelegate.cpp Example File

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 #include "bookdelegate.h"

 #include <QtWidgets>

 BookDelegate::BookDelegate(QObject *parent)
     : QSqlRelationalDelegate(parent), star(QPixmap(":images/star.png"))
 {
 }

 void BookDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                            const QModelIndex &index) const
 {
     if (index.column() != 5) {
         QStyleOptionViewItemV3 opt = option;
         opt.rect.adjust(0, 0, -1, -1); // since we draw the grid ourselves
         QSqlRelationalDelegate::paint(painter, opt, index);
     } else {
         const QAbstractItemModel *model = index.model();
         QPalette::ColorGroup cg = (option.state & QStyle::State_Enabled) ?
             (option.state & QStyle::State_Active) ? QPalette::Normal : QPalette::Inactive : QPalette::Disabled;

         if (option.state & QStyle::State_Selected)
             painter->fillRect(option.rect, option.palette.color(cg, QPalette::Highlight));

         int rating = model->data(index, Qt::DisplayRole).toInt();
         int width = star.width();
         int height = star.height();
         int x = option.rect.x();
         int y = option.rect.y() + (option.rect.height() / 2) - (height / 2);
         for (int i = 0; i < rating; ++i) {
             painter->drawPixmap(x, y, star);
             x += width;
         }
         drawFocus(painter, option, option.rect.adjusted(0, 0, -1, -1)); // since we draw the grid ourselves
     }

     QPen pen = painter->pen();
     painter->setPen(option.palette.color(QPalette::Mid));
     painter->drawLine(option.rect.bottomLeft(), option.rect.bottomRight());
     painter->drawLine(option.rect.topRight(), option.rect.bottomRight());
     painter->setPen(pen);
 }

 QSize BookDelegate::sizeHint(const QStyleOptionViewItem &option,
                                  const QModelIndex &index) const
 {
     if (index.column() == 5)
         return QSize(5 * star.width(), star.height()) + QSize(1, 1);

     return QSqlRelationalDelegate::sizeHint(option, index) + QSize(1, 1); // since we draw the grid ourselves
 }

 bool BookDelegate::editorEvent(QEvent *event, QAbstractItemModel *model,
                                const QStyleOptionViewItem &option,
                                const QModelIndex &index)
 {
     if (index.column() != 5)
         return QSqlRelationalDelegate::editorEvent(event, model, option, index);

     if (event->type() == QEvent::MouseButtonPress) {
         QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
         int stars = qBound(0, int(0.7 + qreal(mouseEvent->pos().x()
             - option.rect.x()) / star.width()), 5);
         model->setData(index, QVariant(stars));
         return false; //so that the selection can change
     }

     return true;
 }

 QWidget *BookDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                                     const QModelIndex &index) const
 {
     if (index.column() != 4)
         return QSqlRelationalDelegate::createEditor(parent, option, index);

     // for editing the year, return a spinbox with a range from -1000 to 2100.
     QSpinBox *sb = new QSpinBox(parent);
     sb->setFrame(false);
     sb->setMaximum(2100);
     sb->setMinimum(-1000);

     return sb;
 }