QGraphicRectItem update colour in foreach statement

[Docas]

Thank you for your help once more, its working now, it was an invalid pointer like you said. Concerning the clone() , its the only way I knew how to retrieve the object instances, I am still newbie in this. I am going to try and implement as you advise.Thank you.

I got another question please if I am still allowed. The nodes(QGraphicsRectItems) in the scene keeps crossing paths. I know I am supposed to set the setPos() for each of the nodes on the scene but I do not how to store the items so that I can set individual setPos(). I read my data from the object instance like this:

void GatewayWidget::addRect(DM::Object *_pTitle)
{
 
		C2DM::RouteState *pRoute = (C2DM::RouteState*)_pTitle;
                 QGraphicsRectItem *rectangle;
		QGraphicsTextItem *text;
 
		text = scene->addText(QString::fromStdString(pRoute->m_strSource));// pRoute->Source may contain 4, 8 or any number of nodes that are retried from the data
             text->setPos(600, (qrand() % 400));  //try to setpos() but its ugly
                rectangle = new QGraphicsRectItem(QRectF(0, 0, 60, 60), text); //then put it in QGraphicsRectItems

void GatewayWidget::addRect(DM::Object *_pTitle)
{
	
		C2DM::RouteState *pRoute = (C2DM::RouteState*)_pTitle;
                 QGraphicsRectItem *rectangle;
		QGraphicsTextItem *text;

		text = scene->addText(QString::fromStdString(pRoute->m_strSource));// pRoute->Source may contain 4, 8 or any number of nodes that are retried from the data
             text->setPos(600, (qrand() % 400));  //try to setpos() but its ugly
                rectangle = new QGraphicsRectItem(QRectF(0, 0, 60, 60), text); //then put it in QGraphicsRectItems

To copy to clipboard, switch view to plain text mode 

I tried to set randomly position them, which is not ideal. Now this makes the QGraphicsLineItems *line that I use to connect source and destination to cross paths(please see attachment). So I am asking for your guidance, on how I can store the nodes(pRoute->Source) ,which will enable me to retrieve and setPos() for each QGraphicRectItem?

[d_stranz]

how I can store the nodes

I think you need to do some research online. Start by using Google for "directed graph c++" and read about the different ways to implement graph data structures. (Your DM Object trees and the matching QGraphicsItem tree) are directed graphs in computer science / mathematics terminology.

Next you need to use Google to find information on "directed graph layout". There are many ways to lay out graphs, but this Wikipedia article on "Layered graph drawing" might be good for your needs. To draw a layered graph, you create a "row" for each level in your tree. You then count the number of nodes at each level, and the divide the row up into that many boxes and put one node in each box, under the parent it belongs to. You can see an example on the Wikipedia page.