Program crashes if i want to clear() a combobox!?

[Terreox]

Hi there
i dont know how to solve one problem.
I designed a controlpanel for my program with QtDesigner and added controlpanel.cpp and controlpanel.h to be able to add more functionality.
Now i have a problem:
On the GUI there are several Comboboxes. If a new ControlPanel is created all comboboxes should be cleared and initialized with some items.

Controlpanel.h

#ifndef CONTROLPANEL_H
#define CONTROLPANEL_H
#include <QMainWindow>
#include "ui_controlpanel.h"
 
class ControlPanel : public QMainWindow, public Ui::ControlPanel
{
    Q_OBJECT
 
public:
    ControlPanel();
 
private:
    void initStatusVectors();
    void setComboBoxes();
 
    QVector<QString> statusVec;
};
 
 
#endif // CONTROLPANEL_H

#ifndef CONTROLPANEL_H
#define CONTROLPANEL_H
#include <QMainWindow>
#include "ui_controlpanel.h"

class ControlPanel : public QMainWindow, public Ui::ControlPanel
{
    Q_OBJECT

public:
    ControlPanel();

private:
    void initStatusVectors();
    void setComboBoxes();

    QVector<QString> statusVec;
};


#endif // CONTROLPANEL_H

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And this is Controlpanel.cpp

#include <QMainWindow>
#include <QtGui>
#include "controlpanel.h"
 
//INITIALIZE STATUS-VECTOR
void ControlPanel::initStatusVectors()
{
    statusVec.push_back("1");
    statusVec.push_back("2");
    statusVec.push_back("3");
    statusVec.push_back("4");
    statusVec.push_back("5");
    statusVec.push_back("6");
    statusVec.push_back("7");
    statusVec.push_back("8");
    statusVec.push_back("9");
}
 
void ControlPanel::setComboBoxes()
{
    this->combStatus1->clear();
}
 
ControlPanel::ControlPanel(QWidget *parent)
    : QMainWindow(parent)
{
    //INITIALIZE STATUS-VECTOR
    initStatusVectors();
 
    setComboBoxes();
 
    setupUi(this);
}

#include <QMainWindow>
#include <QtGui>
#include "controlpanel.h"

//INITIALIZE STATUS-VECTOR
void ControlPanel::initStatusVectors()
{
    statusVec.push_back("1");
    statusVec.push_back("2");
    statusVec.push_back("3");
    statusVec.push_back("4");
    statusVec.push_back("5");
    statusVec.push_back("6");
    statusVec.push_back("7");
    statusVec.push_back("8");
    statusVec.push_back("9");
}

void ControlPanel::setComboBoxes()
{
    this->combStatus1->clear();
}

ControlPanel::ControlPanel(QWidget *parent)
    : QMainWindow(parent)
{
    //INITIALIZE STATUS-VECTOR
    initStatusVectors();

    setComboBoxes();

    setupUi(this);
}

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If i leave out setComboBoxes() everything works fine i guess. Nothing bad happens.
But if i call setComboBoxes(); the program crashes before showing the GUI. So i press CTRL+R and then the crash message of windows appears
"ControlPanel has crashed and so on..."

I really dont know whats the problem is? Can anyone help me?

Greetz

[FelixB]

your program crashes because "combStatus1" is NULL. you have to call "setupUi(this)" to initialize your ui.

[stampede]

Where do you initialize this->combStatus1 ?
edit: you have to initialize ui first, then use it, not the other way around

[Terreox]

Oh ok thanks Yes it makes sense to initialize the ui first^^