QTreeView draw drop indicator

Question

I need to implement rows moving via drag-n-drop in QTreeView and show the drop indicator between rows. I am wondering if there is a way to override indicator drawing, so it is displayed for all levels of hierarchy between rows only (not the rectangle around the item), the line must be as wide as the entire row (not as the one column).

Answer 1

It is possible by modyfing style used to draw widget. My attempt seemed to work well, but it's a bit of cheating the qt's style system, so i cannot guarante that it will work under all possible styles on all platforms. So here it is:

class myViewStyle: public QProxyStyle{
public:
    myViewStyle(QStyle* style = 0);

    void drawPrimitive ( PrimitiveElement element, const QStyleOption * option, QPainter * painter, const QWidget * widget = 0 ) const;
};

myViewStyle::myViewStyle(QStyle* style)
     :QProxyStyle(style)
{}

void myViewStyle::drawPrimitive ( PrimitiveElement element, const QStyleOption * option, QPainter * painter, const QWidget * widget) const{
    if (element == QStyle::PE_IndicatorItemViewItemDrop && !option->rect.isNull()){
        QStyleOption opt(*option);
        opt.rect.setLeft(0);
        if (widget) opt.rect.setRight(widget->width());
        QProxyStyle::drawPrimitive(element, &opt, painter, widget);
        return;
    }
    QProxyStyle::drawPrimitive(element, option, painter, widget);
}

myView::myView(QWidget *parent) :
    QTreeView(parent)
{
    setStyle(new myViewStyle(style()));
}