[SOLVED]mousePress event QGraphicsView

BlackMamba

Hello,

I have a subclassed QGraphicsView and added mousePressEvent. When clicked on the view, it creates a QGraphicsItem at the same location (via QGraphicsScene). This QGraphicsItem has also a mousePressEvent.

I want that when you click on the item created, it doesnt activate the event on the scene. (otherwise it creates a second item at the click location).

How could I achieve that?

Cheers,

BlackMamba

Still no idea? Raven is not around? :)

Cheers,

raven-worx

patience is the key ;)
your thread just has 25 views so far.

Did i understand you correct that you re-implemented the mousePressEvent() handler of the QGraphicsView subclass? Meaning QGraphicsView::mousePressEvent()?

raven-worx

i assume you did... so try the following:

QGraphicsScene is responsible for forwarding the events to the items.
So you should subclass the scene and re-implement the mousePressEvent() like this:
@
void MyGraphicsScene::mousePressEvent ( QGraphicsSceneMouseEvent * mouseEvent )
{
QGraphicsScene::mousePressEvent ( mouseEvent );
if( mouseEvent->isAccepted() )
return;

 //if the event has not been processed by an item create a new item here

}
@

This only works if you have accepted the mouseEvent in your item!

BlackMamba

Hello raven :)

Thanks for your answer !

[quote author="raven-worx" date="1381411476"]patience is the key ;) your thread just has 25 views so far. Did i understand you correct that you re-implemented the mousePressEvent() handler of the QGraphicsView subclass? Meaning QGraphicsView::mousePressEvent()?[/quote]

yes I subclassed like that.

I will try to subclass the scene as you mentionned it. My question is : is that enough to subclass the scene by adding mousePressEvent without subclassing the view or do I need both? (subclass scene and view)

raven-worx

only the scene.

BlackMamba

Dear raven, I tried :

@
void XCustomGraphicsScene::mousePressEvent ( QGraphicsSceneMouseEvent * event )
{
QGraphicsScene::mousePressEvent ( event );
if( event->isAccepted() )
{
return;
}
else{
emit signalCreateRectangle(event->pos());
qDebug() << event->pos();
qDebug() << this->width();
qDebug() << this->height();
update();
QGraphicsScene::mousePressEvent(event);
}
//if the event has not been processed by an item create a new item here
}
@

and the qDebug() << event->pos(); only displays QPointF(0,0), wherever I click ...

raven-worx

use event->scenePos()

and also don't call the base class implementation a second time.

BlackMamba

Dear raven,

it works if I add :

@QGraphicsScene::mousePressEvent ( event );@

at the end and not at the beginning. However, when moving the item around, it creates a second rectangle when I click to select it ...
It only works if I dont move the item ...

Any idea? :)

raven-worx

[quote author="BlackMamba" date="1381426485"]
it works if I add :

@QGraphicsScene::mousePressEvent ( event );@

at the end and not at the beginning.
[/quote]
This doesnt make sense.

[quote author="BlackMamba" date="1381426485"]
However, when moving the item around, it creates a second rectangle when I click to select it ...
[/quote]
I guess that is...when you create a rect item every time you receive a mouse press event?

BlackMamba

It works ! Just needed to add update somewhere else that it draws properly.
Indeed, QGraphicsScene::mousePressEvent ( event ); should be at the beginning.

Thank you so much raven you help me a lot :)