How to manage multi QGraphicsItem

[Marcofe]

Hello,
I've a class Scene extending QGraphicsSceneand to catch click mouse i'm using the function mousePressEvent ( QGraphicsSceneMouseEvent* event ). This function is coded like:

void  Scene::mousePressEvent ( QGraphicsSceneMouseEvent* event ) {
  // set local variables and check if existing station clicked
  qreal x = event->scenePos().x();
  qreal y = event->scenePos().y();
 
  GraphItem _item = dynamic_cast<GraphItem*> ( itemAt ( x, y ) );
 
   if ( GraphItem == 0 && event->button() == Qt::LeftButton ) {
    m_undoStack->push ( new CommandGraphItemAdd ( this, x, y ) );
    emit message ( QString ( "GraphItem add at %1,%2" ).arg ( x ).arg ( y ) );
  }
 
  QGraphicsScene::mousePressEvent ( event );
  this->update();
}

void  Scene::mousePressEvent ( QGraphicsSceneMouseEvent* event ) {
  // set local variables and check if existing station clicked
  qreal x = event->scenePos().x();
  qreal y = event->scenePos().y();

  GraphItem _item = dynamic_cast<GraphItem*> ( itemAt ( x, y ) );

   if ( GraphItem == 0 && event->button() == Qt::LeftButton ) {
    m_undoStack->push ( new CommandGraphItemAdd ( this, x, y ) );
    emit message ( QString ( "GraphItem add at %1,%2" ).arg ( x ).arg ( y ) );
  }
  
  QGraphicsScene::mousePressEvent ( event );
  this->update();
}

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My problem is how to create various QGraphicItem into the mousePressEvent function ? For example i click a button into menu option and a point is selecting, or a circle or other.
My solution is using a switch that reads a value (for example an int value, it set when a button is clicked), but for me isn't optimal solution. What do you think?Exist any different solution?
tnx so much

[JackHammer]

May be you could use factory pattern for creating the graphics items so that you could keep the changes minimal later.

[Marcofe]

JackHammer, I don't know this pattern and this is a way to learn a new thing about programming...so I’m looking for it.
Tnx so much for your answer. I'll inform you for news. Bye