Why do I not see the drop indicator in a QTableView?

// see model for implementing logic of drag this->viewport()->setAcceptDrops(allowDrop); this->setDragEnabled(allowDrag); this->setDropIndicatorShown(true); this->m_model->allowDrop(allowDrop);

I faced the same problem, I tried two options which both worked for me. IIRC, the help came from an answer on SO.

if you are subclassing QTreeView, you can override its paintEvent() method. It is calling by default the drawTree() method and the paintDropIndicator() one (the latter being part of QAbstractItemView private class).

You can call drawTree() from your paintEvent(), and it should override the default drag and drop indicator as well :

class MyTreeView : public QTreeView
{
public:
    explicit MyTreeView(QWidget* parent = 0) : QTreeView(parent) {}

    void paintEvent(QPaintEvent * event)
    {
        QPainter painter(viewport());
        drawTree(&painter, event->region());
    }
};

the other method is to subclass QProxyStyle and overriding the drawPrimitive() method. When you get the element QStyle::PE_IndicatorItemViewItemDrop as a parameter, you can paint it your own way.

The code will look like this:

class MyOwnStyle : public QProxyStyle
{
public:
    MyOwnStyle(QStyle* style = 0) : QProxyStyle(style) {}

    void drawPrimitive(PrimitiveElement element, const QStyleOption* option, QPainter* painter, const QWidget* widget) const
    {
        if (element == QStyle::PE_IndicatorItemViewItemDrop)
        {
            //custom paint here, you can do nothing as well
            QColor c(Qt::white);
            QPen pen(c);
            pen.setWidth(1);

            painter->setPen(pen);
            if (!option->rect.isNull())
                painter->drawLine(option->rect.topLeft(), option->rect.topRight());
        }
        else
        {
            // the default style is applied
            QProxyStyle::drawPrimitive(element, option, painter, widget);
        }
    }
};

Recommended topics

Hot tags