QGraphicsScene segmentation fault

**maxpower** · 20th November 2006, 18:17

I have the following code

Qt Code:

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#include <QGraphicsScene>
#include <QMessageBox>
#include "proFootballOnline.h"
//
ProFootballOnline::ProFootballOnline( QWidget * parent, Qt::WFlags f) 
	: QMainWindow(parent, f)
{
	setupUi(this);
}
 
void ProFootballOnline::Init ()
{
 
}
void ProFootballOnline::on_initPB_clicked()
{
	QGraphicsScene scene;
	scene.addText("Bob");
	//scene.setItemIndexMethod(QGraphicsScene::NoIndex);
	//fieldGV->setBackgroundBrush(Qt::green);
	fieldGV->setScene(&scene);
	fieldGV->update();
}

#include <QGraphicsScene>
#include <QMessageBox>
#include "proFootballOnline.h"
//
ProFootballOnline::ProFootballOnline( QWidget * parent, Qt::WFlags f) 
	: QMainWindow(parent, f)
{
	setupUi(this);
}

void ProFootballOnline::Init ()
{
	
}
void ProFootballOnline::on_initPB_clicked()
{
	QGraphicsScene scene;
	scene.addText("Bob");
	//scene.setItemIndexMethod(QGraphicsScene::NoIndex);
	//fieldGV->setBackgroundBrush(Qt::green);
	fieldGV->setScene(&scene);
	fieldGV->update();
}

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When the program runs and the initPB is clicked, the program closes a does a core dump. I ran it through a debugger and, depending on what I try to do with the scene, faults on various things (setBackground, setItemIndexMode). The fieldGV is a QGraphicsView I have on my main window. Any ideas on what is causing the crash? If I place a QMessageBox at the end of the slot, i can see the contents of fieldGV update properly but closing the box sets off the core dump.

mAx

**e8johan** · 20th November 2006, 18:23

Your problem is that scene is allocated on the stack, e.g. you do not write ... *scene = new... This means that scene is automatically deleted as soon as you leave the slot.