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
Qt Code: 
  1. public slots:
  2.     void go_clicked();
  3.  
  4. private:
  5.     group ingrp;
  6.     QGraphicsScene *inscene;
  7.     bool *insel;
  8.     bool *inblink;
  9.  
  10.     QLabel *lbl_grp;
  11.     QComboBox *combo_pl;
  12.     QPushButton *btn_grp;
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groupwidget.cpp
Qt Code: 
  1. groupWidget::groupWidget(const group &grp, QGraphicsScene *scene, bool *sel, bool *blink)
  2. {
  3.     ingrp = grp;
  4.     inscene = scene;
  5.     insel = sel;
  6.     inblink = blink;
  7.  
  8.     combo_pl = new QComboBox;
  9.  
  10.     combo_pl->addItem("---Select---");
  11.  
  12.     foreach (place p, grp.building)
  13.         combo_pl->addItem(p.placename);
  14.  
  15.     combo_pl->setMinimumWidth(200);
  16.  
  17.     btn_go = new QPushButton;
  18.     btn_go->setText("Go");
  19.     btn_go->setMaximumWidth(50);
  20.  
  21.     lbl_grp = new QLabel;
  22.     lbl_grp->setText(grp.grpname);
  23.  
  24.     QGridLayout *layout = new QGridLayout;
  25.     layout->addWidget(lbl_grp, 0, 0);
  26.     layout->addWidget(combo_pl, 1, 0);
  27.     layout->addWidget(btn_go,1,1);
  28.  
  29.     setLayout(layout);
  30.     connect(btn_go, SIGNAL(clicked()), this, SLOT(go_clicked()));
  31. }
  32.  
  33. void groupWidget::go_clicked()
  34. {
  35.     QPoint pt;
  36.     bool stat = false;
  37.  
  38.     foreach (place p, ingrp.building)
  39.     {
  40.         if ((combo_pl->currentText().trimmed().compare(p.placename)) == 0)
  41.         {
  42.             bool ok;
  43.             pt.setX(p.x.toInt(&ok,10));
  44.             pt.setY(p.y.toInt(&ok,10));
  45.             stat = true;
  46.         }
  47.  
  48.         if (stat)
  49.             break;
  50.     }
  51.  
  52.     if (!stat) {
  53.         *insel = false;
  54.         *inblink = false;
  55.         return;
  56.     }
  57.  
  59.     item->setRect(pt.x(), pt.y(), ellsize, ellsize);
  60.     item->setBrush(Qt::red);
  61.     inscene->addItem(item); //seg fault
  62.  
  63.     *insel = true;
  64.     *inblink = true;
  65. }
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disp.h
Qt Code: 
  1. private:
  2.     void createPlace();
  3.     QWidget *createCellWidget(group grp);
  4.     ....
  5.     bool blink_stat, sel_item;
  7.     ....
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disp.cpp
Qt Code: 
  1. disp::disp(mapinfo in_map)
  2. {
  3.     ....
  4.     scene = new QGraphicsScene;
  5.     scene->setSceneRect(0, 0, 600, 600);
  6.     ....
  7. }
  8. ....
  9. ....
  10. ....
  11. QWidget *disp::createCellWidget(group grp)
  12. {
  13.     groupWidget *pgroupWidget = new groupWidget(grp, scene, &sel_item, &blink_stat);
  14.     return pgroupWidget;
  15. }
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