[Interest] QGaphicsItem deletion

[Reinhardt Behm]

On Thursday 16 June 2016 17:44:30 Konstantin Shegunov wrote:
> Hello,
> 
> On Wed, Jun 15, 2016 at 7:00 PM, Igor Mironchik <igor.mironchik at gmail.com>
> 
>  wrote:
> > Exactly. I need to Line be as parent of handles but they should be
> > parented to the scene (read form in my app) because I need boundingRect()
> > to return exactly bounding rectangle of the line without handles. An I
> > need
> > handles to be removed with the Line if Line deleted.
> 
> I didn't have time to check if the graphics view manages the children the
> same way as QObject hierarchies, but there's the QEvent::ChildAdded and
> QEvent::ChildRemoved events. If they're fired within the graphics items'
> object tree you could intercept them and with a bit of fiddling ultimately
> null your handle pointers in Line if Qt had deleted the handles.

It does manage them in a similar way.

I had a similar problem, where QGraphicsItems where managed by real QObjects 
and of course belonged to a QGraphicsScene derived class.

The dtor of my class is

GeoMapScene::~GeoMapScene()
{
	emit aboutToBeDestroyed(this);
}

This signal is emitted before the dtor of QGraphicsScene comes into play.
It is catched by the managing QObject and informs them of the coming death of 
their QGraphicsItems.

-- 
Best Regards

Reinhardt