segmentation fault!!

[Yayati.Ekbote]

Hi guys,

I am using old version of Qt which comes with the Friendly arm device for embedded development.
It consists of Qtopia 2.2.0 with Qt2 designer.

I prepared a small application for testing using a QListView. I drew ListView widget on my form which i named ListView and named ny UI file as myapp_base.ui.

In my header file i wrote-

#ifndef MYAPP_H
#define MYAPP_H
 
#include "myapp_base.h"
 
class MyApp : public MyAppBase
{
public:
        MyApp(QWidget *parent=0,const char *name=0, WFlags fl=0);
        ~MyApp();
 
}

#ifndef MYAPP_H
#define MYAPP_H

#include "myapp_base.h"

class MyApp : public MyAppBase
{
public:
        MyApp(QWidget *parent=0,const char *name=0, WFlags fl=0);
        ~MyApp();

}

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My implementation file is following-

#include "myapp.h"
#include <qlistview.h>
 
MyApp::MyApp(QWidget *parent, const char *name,WFlags fl):
MyAppBase(parent,name,fl)
{
   QListViewItem *newItem;
   newItem->setText(0,"newItem");
   ListView->insertItem(newItem);     
}
 
MyApp::~MyApp()
{
}

#include "myapp.h"
#include <qlistview.h>

MyApp::MyApp(QWidget *parent, const char *name,WFlags fl):
MyAppBase(parent,name,fl)
{
   QListViewItem *newItem;
   newItem->setText(0,"newItem");
   ListView->insertItem(newItem);     
}

MyApp::~MyApp()
{
}

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And my main file is-

#include "myapp.h"
#include <qapplication.h>
 
int main(int argc, char *argv[])
{
    QApplication app(argc,argv);
    MyApp *obj;
    obj->show();
 
   return app.exec();
}

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

int main(int argc, char *argv[])
{
    QApplication app(argc,argv);
    MyApp *obj;
    obj->show();

   return app.exec();
}

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My code gets compiled successfully but gives a runtime segmentation fault. What is the problem??

[wysota]

You didn't create the item, just a pointer to it.

[Yayati.Ekbote]

Ok, But then when i wrote main like this-

#include "myapp.h"
#include <qapplication.h>
 
int main(int argc, char *argv[])
{
   QApplication app(argc,argv);
   MyApp obj;
   obj.show();
 
  return app.exec();
}

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

int main(int argc, char *argv[])
{
   QApplication app(argc,argv);
   MyApp obj;
   obj.show();

  return app.exec();
}

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It gave me following error-

error main.cpp.7.there is no call for MyApp::MyApp()
candidates for the call are MyApp::MyApp(QWidget *parent,const char *name, WFlags fl);
candidates to the call are MyApp::MyApp(const MyApp&);

Also when i tried this..

MyApp obj=new MyApp;

MyApp obj=new MyApp;

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or

MyApp obj= new MyApp();

MyApp obj= new MyApp();

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or

MyApp obj=new MyApp(ListView,"myapp");

MyApp obj=new MyApp(ListView,"myapp");

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it gave the same error!!!!

what to do???

[wysota]

The error was not in main() but in MyApp::MyApp().

Please do yourself a favour and refresh your C++ knowledge.

[Yayati.Ekbote]

Thanks very much...problem solved!!!