Memory Trouble

[nimrod]

This is my first major project using Qt, and I have a bit of a problem.
I subclassed QMainWindow for my program, and got the layout and menus to work.
The layout is made of QSplitters and in the main view I have a QWidgetStack.
I wanted to keep the widget stack id's in integer variables, so I added two variables in the class definition,and tried:

widgetStackItemId=mainview->id(wigetPointer);

And later used:

mainview->raiseWidget(widgetStackItemId);

Now, this worked with one of the variables, but as soon as I tried using another variable, it started giving me segmentation faults.
At first, I thought it was related to the QWidgetStack, but it seems that as soon as I assign a value to the second variable (can be just a number), the program crashes with a seg fault.
I think I made a mistake with a pointer, but I don't know which one. Here is a code based on my real code. I changed variable and function names, and shortened some boring bits (menu items). The code works like that, I think the bug is a matter of scale.

Header (mymainwindow.h):

#ifndef MYMAINWINDOW_H
#define MYMAINWINDOW_H
 
#include <qmainwindow.h>
#include <qmenubar.h>
#include <qpopupmenu.h>
#include <qsplitter.h>
#include <qlistbox.h>
#include <qtable.h>
#include <qscrollview.h>
#include <qwidgetstack.h>
#include <qstringlist.h>
#include <qtextedit.h>
 
 
class MyMainWindow: public QMainWindow
{
    Q_OBJECT
public:
    MyMainWindow(QWidget *parent=0,const char *name=0);
protected:
    //CloseEvent is called whenever the user closes the program's window.
    void CloseEvent(QCloseEvent *event);
 
private slots:
    bool mnuFileQuit();
    void mnuViewItem();
 
    void leftPane1Changed();
private:
 
    void initLayout();
    void initMenus();
 
    void createMainWidget1();
    void createMainWidget2();
 
    QSplitter *mainsplitter;
    QSplitter *leftsplitter;
    QWidgetStack *mainview;
    QListBox *leftPane1;
    QListBox *leftPane2;
 
    //id's in the widget stack:
    int widgetstackid1;
    int widgetstackid2;
 
    //Now actual menu items (rather than their functions) are defined:
    QPopupMenu *fileMenu;
    QPopupMenu *viewMenu;
};
#endif

#ifndef MYMAINWINDOW_H
#define MYMAINWINDOW_H

#include <qmainwindow.h>
#include <qmenubar.h>
#include <qpopupmenu.h>
#include <qsplitter.h>
#include <qlistbox.h>
#include <qtable.h>
#include <qscrollview.h>
#include <qwidgetstack.h>
#include <qstringlist.h>
#include <qtextedit.h>


class MyMainWindow: public QMainWindow
{
    Q_OBJECT
public:
    MyMainWindow(QWidget *parent=0,const char *name=0);
protected:
    //CloseEvent is called whenever the user closes the program's window.
    void CloseEvent(QCloseEvent *event);
    
private slots:
    bool mnuFileQuit();
    void mnuViewItem();
    
    void leftPane1Changed();
private:
    
    void initLayout();
    void initMenus();
    
    void createMainWidget1();
    void createMainWidget2();
    
    QSplitter *mainsplitter;
    QSplitter *leftsplitter;
    QWidgetStack *mainview;
    QListBox *leftPane1;
    QListBox *leftPane2;
    
    //id's in the widget stack:
    int widgetstackid1;
    int widgetstackid2;
    
    //Now actual menu items (rather than their functions) are defined:
    QPopupMenu *fileMenu;
    QPopupMenu *viewMenu;
};
#endif

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Implementation:

#include "mymainwindow.h"
#include <qapplication.h>
 
MyMainWindow::MyMainWindow(QWidget *parent,const char *name):QMainWindow(parent,name){
    widgetstackid1=0;
    widgetstackid2=0;      //In the real program, this line causes a seg fault.
 
    initLayout();
    initMenus();
}
void MyMainWindow::initLayout(){
    mainsplitter=new QSplitter(Qt::Horizontal,this);
    setCentralWidget(mainsplitter);
 
    leftsplitter=new QSplitter(Qt::Vertical,mainsplitter);
    leftPane1=new QListBox(leftsplitter);
    leftPane1->insertItem("Item 0");
    leftPane1->insertItem("Item 1");
 
    connect(leftPane1,SIGNAL(currentChanged ( QListBoxItem * )),this,SLOT(leftPane1Changed()));
    leftPane2=new QListBox(leftsplitter);
 
    mainview=new QWidgetStack(mainsplitter);
 
    createMainWidget1();
    createMainWidget2();
}
 
void MyMainWindow::initMenus(){
    fileMenu=new QPopupMenu (this);
    viewMenu=new QPopupMenu(this);
 
    fileMenu->insertItem("&Quit",this,SLOT(mnuFileQuit()));
 
 
    viewMenu->insertItem("View Menu Item",this,SLOT(mnuViewItem()));
 
    menuBar()->insertItem("&File",fileMenu);
    menuBar()->insertItem("&View",viewMenu);
}
 
void MyMainWindow::createMainWidget1(){
    QTable *mainWidget1Table = new QTable( 4, 2, mainview );
    mainWidget1Table->setLeftMargin(0);
    mainWidget1Table->setReadOnly(true);
    QStringList labels;
    labels.append("col 1");
    labels.append("col 2");
 
    int i;
    for(i=0;i<2;i++){
        mainWidget1Table->setColumnWidth(i,60);
    }
    mainWidget1Table->setColumnLabels(labels);
    mainWidget1Table->setSorting(true);
 
    mainview->addWidget(mainWidget1Table);
 
    widgetstackid1=mainview->id(mainWidget1Table);
}
 
void MyMainWindow::createMainWidget2(){
    QTextEdit *mainWidget2Text;
    mainWidget2Text=new QTextEdit(mainview);
    mainWidget2Text->setReadOnly(true);
    mainWidget2Text->setText("<h1>hello</h1>world.");
    mainview->addWidget(mainWidget2Text);
    widgetstackid2=mainview->id(mainWidget2Text);      //In the real program, this line causes a seg fault.
}
 
//Menu functions
void MyMainWindow::mnuViewItem(){
    qWarning("mnuViewItem() called.");
}
bool MyMainWindow::mnuFileQuit(){
    return (close(true));
}
 
 
void MyMainWindow::leftPane1Changed(){
    int currentItem=leftPane1->currentItem();
    switch(currentItem){
        case 0:
            mainview->raiseWidget(widgetstackid1);
            break;
        case 1:
            mainview->raiseWidget(widgetstackid2);
            break;
    }
}
 
//Main program
int main(int argc,char *argv[]){
    QApplication app(argc,argv);
    MyMainWindow windowThing;
    app.setMainWidget(&windowThing);
    windowThing.show();
 
    return app.exec();   
}

#include "mymainwindow.h"
#include <qapplication.h>

MyMainWindow::MyMainWindow(QWidget *parent,const char *name):QMainWindow(parent,name){
    widgetstackid1=0;
    widgetstackid2=0;      //In the real program, this line causes a seg fault.
    
    initLayout();
    initMenus();
}
void MyMainWindow::initLayout(){
    mainsplitter=new QSplitter(Qt::Horizontal,this);
    setCentralWidget(mainsplitter);
    
    leftsplitter=new QSplitter(Qt::Vertical,mainsplitter);
    leftPane1=new QListBox(leftsplitter);
    leftPane1->insertItem("Item 0");
    leftPane1->insertItem("Item 1");
    
    connect(leftPane1,SIGNAL(currentChanged ( QListBoxItem * )),this,SLOT(leftPane1Changed()));
    leftPane2=new QListBox(leftsplitter);
    
    mainview=new QWidgetStack(mainsplitter);
    
    createMainWidget1();
    createMainWidget2();
}

void MyMainWindow::initMenus(){
    fileMenu=new QPopupMenu (this);
    viewMenu=new QPopupMenu(this);

    fileMenu->insertItem("&Quit",this,SLOT(mnuFileQuit()));
    
    
    viewMenu->insertItem("View Menu Item",this,SLOT(mnuViewItem()));

    menuBar()->insertItem("&File",fileMenu);
    menuBar()->insertItem("&View",viewMenu);
}

void MyMainWindow::createMainWidget1(){
    QTable *mainWidget1Table = new QTable( 4, 2, mainview );
    mainWidget1Table->setLeftMargin(0);
    mainWidget1Table->setReadOnly(true);
    QStringList labels;
    labels.append("col 1");
    labels.append("col 2");
    
    int i;
    for(i=0;i<2;i++){
        mainWidget1Table->setColumnWidth(i,60);
    }
    mainWidget1Table->setColumnLabels(labels);
    mainWidget1Table->setSorting(true);
    
    mainview->addWidget(mainWidget1Table);
    
    widgetstackid1=mainview->id(mainWidget1Table);
}

void MyMainWindow::createMainWidget2(){
    QTextEdit *mainWidget2Text;
    mainWidget2Text=new QTextEdit(mainview);
    mainWidget2Text->setReadOnly(true);
    mainWidget2Text->setText("<h1>hello</h1>world.");
    mainview->addWidget(mainWidget2Text);
    widgetstackid2=mainview->id(mainWidget2Text);      //In the real program, this line causes a seg fault.
}

//Menu functions
void MyMainWindow::mnuViewItem(){
    qWarning("mnuViewItem() called.");
}
bool MyMainWindow::mnuFileQuit(){
    return (close(true));
}


void MyMainWindow::leftPane1Changed(){
    int currentItem=leftPane1->currentItem();
    switch(currentItem){
        case 0:
            mainview->raiseWidget(widgetstackid1);
            break;
        case 1:
            mainview->raiseWidget(widgetstackid2);
            break;
    }
}

//Main program
int main(int argc,char *argv[]){
    QApplication app(argc,argv);
    MyMainWindow windowThing;
    app.setMainWidget(&windowThing);
    windowThing.show();
    
    return app.exec();   
}

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