QTreeWidget crash (improver use?)

[csernai.csaba]

Hello!

I created a QTreeWidget with QToolButtons on sub level items, and by clicking on the button it should be removed from the treewidget with it's QTreeWidgetItem.
The problem is when i expand the first top level item, it's crashes.

May i use QTreeWidget improperly?
Please help!

Here is the code representing my problem:

#ifndef TRASH2_H
#define TRASH2_H
 
#include <QtGui/QMainWindow>
#include <QToolButton>
#include <QStringList>
#include "ui_trash2.h"
 
class trash2 : public QMainWindow
{
	Q_OBJECT
 
public:
	trash2(QWidget *parent = 0, Qt::WFlags flags = 0)
	: QMainWindow(parent, flags)
	{
		ui.setupUi(this);
 
		QTreeWidgetItem* item = 0;
		item = addTopLevelItem( 0 );
		addSubLevelItem( item, 0 );
		addSubLevelItem( item, 1 );
		addSubLevelItem( item, 2 );
 
	}
 
	~trash2()
	{
 
	}
 
	QTreeWidgetItem* addTopLevelItem(int i)
	{
		QTreeWidgetItem* item = 0;
		QStringList list;
		list << QString("Top%1").arg(i);
		item = new QTreeWidgetItem( list );
		ui.treeWidget->addTopLevelItem( item );
 
		return item;
	}
 
	void addSubLevelItem(QTreeWidgetItem* parentItem, int i)
	{
		QTreeWidgetItem* item = 0;
		QToolButton* button = 0;
		QStringList list;
		item = new QTreeWidgetItem( parentItem );
		button = new QToolButton( ui.treeWidget );
		button->setText( QString("button%1").arg(i) );
		button->setToolButtonStyle( Qt::ToolButtonTextBesideIcon );
		button->setAutoRaise( true );
		button->setChecked( false );
 
		connect( button, SIGNAL( pressed() ), this, SLOT( buttonPressed() ) );
		parentItem->addChild( item );
		vmi[button] = item;
		ui.treeWidget->setItemWidget( item, 0, button );
	}
 
public slots:
	void buttonPressed()
	{
		QToolButton* button = dynamic_cast<QToolButton* >( sender() );
		if ( button )
		{
			QTreeWidgetItem* item = vmi[button];
			vmi.remove( button );
			button->disconnect();
			button->deleteLater();
			QTreeWidgetItem* parent = item->parent();
			if ( parent )
			{
				parent->removeChild( item );
			}
			delete item;
		}
	}
 
private:
	Ui::trash2Class ui;
	QMap<QToolButton* , QTreeWidgetItem* > vmi;
};
 
#endif // TRASH2_H

#ifndef TRASH2_H
#define TRASH2_H

#include <QtGui/QMainWindow>
#include <QToolButton>
#include <QStringList>
#include "ui_trash2.h"

class trash2 : public QMainWindow
{
	Q_OBJECT

public:
	trash2(QWidget *parent = 0, Qt::WFlags flags = 0)
	: QMainWindow(parent, flags)
	{
		ui.setupUi(this);

		QTreeWidgetItem* item = 0;
		item = addTopLevelItem( 0 );
		addSubLevelItem( item, 0 );
		addSubLevelItem( item, 1 );
		addSubLevelItem( item, 2 );

	}

	~trash2()
	{

	}

	QTreeWidgetItem* addTopLevelItem(int i)
	{
		QTreeWidgetItem* item = 0;
		QStringList list;
		list << QString("Top%1").arg(i);
		item = new QTreeWidgetItem( list );
		ui.treeWidget->addTopLevelItem( item );
		
		return item;
	}

	void addSubLevelItem(QTreeWidgetItem* parentItem, int i)
	{
		QTreeWidgetItem* item = 0;
		QToolButton* button = 0;
		QStringList list;
		item = new QTreeWidgetItem( parentItem );
		button = new QToolButton( ui.treeWidget );
		button->setText( QString("button%1").arg(i) );
		button->setToolButtonStyle( Qt::ToolButtonTextBesideIcon );
		button->setAutoRaise( true );
		button->setChecked( false );

		connect( button, SIGNAL( pressed() ), this, SLOT( buttonPressed() ) );
		parentItem->addChild( item );
		vmi[button] = item;
		ui.treeWidget->setItemWidget( item, 0, button );
	}

public slots:
	void buttonPressed()
	{
		QToolButton* button = dynamic_cast<QToolButton* >( sender() );
		if ( button )
		{
			QTreeWidgetItem* item = vmi[button];
			vmi.remove( button );
			button->disconnect();
			button->deleteLater();
			QTreeWidgetItem* parent = item->parent();
			if ( parent )
			{
				parent->removeChild( item );
			}
			delete item;
		}
	}

private:
	Ui::trash2Class ui;
	QMap<QToolButton* , QTreeWidgetItem* > vmi;
};

#endif // TRASH2_H

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[tbscope]

First of all, the code you posted is very weird.
Why do you code the implementation in the header? Are you coming from a C# world?

The problem is when i expand the first top level item, it's crashes.

I copied your code and tried it for myself. It doesn't crash for me.
Post the error you get please.

May i use QTreeWidget improperly?

The use of ui is a little bit strange to me.
And you should include QTreeWidgetItem

[csernai.csaba]

First of all, the code you posted is very weird.
Why do you code the implementation in the header? Are you coming from a C# world?

Nope. It's easier to post here. The source and the header is separated in my solution.
And it is a samle code.

I copied your code and tried it for myself. It doesn't crash for me.
Post the error you get please.

I don't know if it matters, i compile it with VS 2008 x64 and run it on a Windows 7 x64 system.

Unhandled exception at 0x65948c50 (QtGuid4.dll) in trash2.exe: 0xC0000005: Access violation reading location 0xffffffffffffffff.

Unhandled exception at 0x65948c50 (QtGuid4.dll) in trash2.exe: 0xC0000005: Access violation reading location 0xffffffffffffffff.

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It's crashes in this part ( should i post the Call Stack? ):

QVariant QTreeModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
    QTreeWidgetItem *itm = item(index);
    if (itm)
        return itm->data(index.column(), role);
    return QVariant();
}

QVariant QTreeModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
    QTreeWidgetItem *itm = item(index);
    if (itm)
        return itm->data(index.column(), role);
    return QVariant();
}

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The use of ui is a little bit strange to me.
And you should include QTreeWidgetItem

Iit was generated using the default Qt Application project settings in VS2008.
I think the QTreeWidget.h includes QTreeWidgetItem and QTreeWidget is included in the ui's header.

[changedsoul]

I know this is an old thread, but its fits by problem. Im using Qt5, and am trying to learn about QTreeWidgets. I am getting a crash each time the app runs. I narrowed it down to when I create the QTreeWidget variable.

int main()
{
.....

QTreeWidget treeWidget; // I crash here

.....
}

The error I get is:
"The inferior stopped because it triggered an exception.
Stopped in thread 0....... Read access violation.

Anyone know what might be wrong?

[giblit]

not sure what your problem is, but why add all the things on the header file?

EDIT:
Sorry it didnt even show any of the otehr comments can this be deleted?

[changedsoul]

Nevermind. I found the error of my ways. I was not doing it as a GUI app. DOH!! Anyways, I started a GUI app and the QTreeWidget works just fine