QToolbar: Trying to reset value of QSpinBox in QToolbar via QToolbutton results crash

Hi!

I'm trying to implement a sort of error-counter in a toolbar. For this error-counter i use a QToolbutton with different icons depending on the state (red for error, green for ok). Addionaly I use a QSpinBox for counting the errors.
Until now, everything is fine.

What I want to implement is the resetting of the spinbox-value by clicking on the toolbutton.
With the following code, the program crashes when I hit the button.

Code:

---

MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::Main Window)
{
    ui->setupUi(this);
    ....
    ui->mainToolBar->addAction(ui->actionLostReset);
    QSpinBox *lostSpinBox = new QSpinBox(ui->mainToolBar);
    lostSpinBox.setMaximum(10000);
    ui->mainToolBar->addWidget(lostSpinBox);
    lostSpinBox->setValue(0);   // here it works
    ...
}
...
void MainWindow::on_actionLostReset_triggered()
{
      if (ui->actionLostReset->isChecked())
      {
            lostSpinBox->setValue(10);  // here it crashes
      }
}

---

If I do the same command to a spinbox in a widget everything is fine.
How can this be?
I'm using Qt 4.8.4. and Qwt 6.1 on a WinXP SP3.

Thanx for your help and please excuse my bad english.

Hi Janoschka,
The problem is your definition : QSpinBox *lostSpinBox
in the constructor mainwindow.

Please edit your code like this :
MainWindow.cpp

Code:

---

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    lostSpinBox = new QSpinBox(ui->mainToolBar);
    lostSpinBox->setMaximum(10000);
    ui->mainToolBar->addWidget(lostSpinBox);
    lostSpinBox->setValue(0); // here it works
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_actionLostReset_triggered()
{
    if (ui->actionLostReset->isChecked())
    {
        lostSpinBox->setValue(10); // here it crashes
    }
}

---

MainWindow.h

Code:

---

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QSpinBox>
 
namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    Ui::MainWindow *ui;
    QSpinBox *lostSpinBox;
 
public slots:
    void on_actionLostReset_triggered();
};
 
#endif // MAINWINDOW_H

---

Best regards,

Toto

Hi Toto!
Thank you very, very much!!!!

I was so dumb and blind, because after your posting I realised I made the correct things in mainwindow.h, but I made some kind of redefinition in mainwindow.c.

Sometimes it's better to have someone to look at the code....

Have a nice day