customwidget and event help

Hi all,

I need got this problem which I have no idea why it happens and how to remedy it.

I got a customWidget (groupwidget) with an event button clicked. I pass a QGraphicsScene pointer in the main class (disp) to the customWidget (groupwidget).

when I add a QGraphicsItem into the QGraphicsScene, I got a seg fault. I am am sure that the inputs to graphicsitem->setRect exists and is correct.

How to solve this problem?

groupwidget.h

Code:

public slots:
    void go_clicked();
 
private:
    group ingrp;
    QGraphicsScene *inscene;
    bool *insel;
    bool *inblink;
 
    QLabel *lbl_grp;
    QComboBox *combo_pl;
    QPushButton *btn_grp;

groupwidget.cpp

Code:

groupWidget::groupWidget(const group &grp, QGraphicsScene *scene, bool *sel, bool *blink)
{
    ingrp = grp;
    inscene = scene;
    insel = sel;
    inblink = blink;
 
    combo_pl = new QComboBox;
 
    combo_pl->addItem("---Select---");
 
    foreach (place p, grp.building)
        combo_pl->addItem(p.placename);
 
    combo_pl->setMinimumWidth(200);
 
    btn_go = new QPushButton;
    btn_go->setText("Go");
    btn_go->setMaximumWidth(50);
 
    lbl_grp = new QLabel;
    lbl_grp->setText(grp.grpname);
 
    QGridLayout *layout = new QGridLayout;
    layout->addWidget(lbl_grp, 0, 0);
    layout->addWidget(combo_pl, 1, 0);
    layout->addWidget(btn_go,1,1);
 
    setLayout(layout);
    connect(btn_go, SIGNAL(clicked()), this, SLOT(go_clicked()));
}
 
void groupWidget::go_clicked()
{
    QPoint pt;
    bool stat = false;
 
    foreach (place p, ingrp.building)
    {
        if ((combo_pl->currentText().trimmed().compare(p.placename)) == 0)
        {
            bool ok;
            pt.setX(p.x.toInt(&ok,10));
            pt.setY(p.y.toInt(&ok,10));
            stat = true;
        }
 
        if (stat)
            break;
    }
 
    if (!stat) {
        *insel = false;
        *inblink = false;
        return;
    }
 
    QGraphicsEllipseItem *item = new QGraphicsEllipseItem;
    item->setRect(pt.x(), pt.y(), ellsize, ellsize);
    item->setBrush(Qt::red);
    inscene->addItem(item); //seg fault
 
    *insel = true;
    *inblink = true;
}

disp.h

Code:

private:
    void createPlace();
    QWidget *createCellWidget(group grp);
    ....
    bool blink_stat, sel_item;
    QGraphicsScene *scene;
    ....

disp.cpp

Code:

disp::disp(mapinfo in_map)
{
    ....
    scene = new QGraphicsScene;
    scene->setSceneRect(0, 0, 600, 600);
    ....
}
....
....
....
QWidget *disp::createCellWidget(group grp)
{
    groupWidget *pgroupWidget = new groupWidget(grp, scene, &sel_item, &blink_stat);
    return pgroupWidget;
}