Opening a new window form crashes.

fatihAyt3kin

Hi everyone,

I am having a problem with opening a new form by clicking a button. Whenever I push on the button which will open a new form, the program crashes and gives me the error 1073741819. I searched the web and found out that it's a access violation. I defined a pointer mProgram in private form of mainwindow.h and tried to show that pointer in void pushbutton. I don't know what i am doing wrong..

This is my mainwindow.cpp
@
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "mainprogram.h"

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{

ui->setupUi(this);

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::on_pushButton_clicked()
{
mProgram->show();

}
@

This is my mainprogram.cpp

@
#include "mainprogram.h"
#include "ui_mainprogram.h"
#include "QApplication"

mainProgram::mainProgram(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::mainProgram)
{
ui->setupUi(this);
}

mainProgram::~mainProgram()
{
delete ui;
}
@

This is my mainwindow.h

@
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "mainprogram.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
void on_MainWindow_iconSizeChanged(const QSize &iconSize);

private slots:

void on_pushButton_clicked();

private:
Ui::MainWindow *ui;
mainProgram *mProgram;
};

#endif // MAINWINDOW_H
@

and this is my mainprogram.h

@
#ifndef MAINPROGRAM_H
#define MAINPROGRAM_H

#include <QMainWindow>
#include <QApplication>

namespace Ui {
class mainProgram;
}

class mainProgram : public QMainWindow
{
Q_OBJECT

public:
explicit mainProgram(QWidget *parent = 0);
~mainProgram();

private:
Ui::mainProgram *ui;

};

#endif // MAINPROGRAM_H

@

I am just trying to open a new form named "mainprogram" from mainwindow. I am new QT and trying to learn some basics and would appreciate any help.. Thank you

fransis

Hi!
can you try put this into the mainwindows.cpp constructor?

mProgram = new mainProgram ();

qxoz

Or better:
@mProgram = new mainProgram (this);@

fatihAyt3kin

Thank you for the replies, but I tired them before and got this error, and honestly couldn't find any piece of solution to this. any suggestions?

error LNK2019: unresolved external symbol "public: __thiscall mainProgram::mainProgram(class QWidget *)" (??0mainProgram@@QAE@PAVQWidget@@@Z) referenced in function "public: __thiscall MainWindow::MainWindow(class QWidget *)" (??0MainWindow@@QAE@PAVQWidget@@@Z)

I

fransis

can you try clean all and then build again? I copy your sorce code and build and run fine. I copied your code and build the code and it run fine on my IDE.