Dialog without parent is not a good idea. If you derive your own class from QObject and an instance of that class is going to create a QDialog, nothing is holding you from adding a member variable of type "QWidget*" to your class to store the pointer to the parent dialog. So when the instance of your class (derived from QObject) is created, pass the parent pointer in constructor or via a separate setParentWidget(QWidtget *ptr)". Then, when the QDialog is created, use the pointer you stored before as the parent. And if you don't like this solution for whatever reason, you can still use "qApp()->activeWindow()" as parent for your QDialog...

@class MyClass : public QObject
{
public:
MyClass(QWidget *ptr)
{
m_parent = ptr;
}

private:
QWidget *m_parent;

void showDialog(void)
{
    QDialog myDlg = new QDialog(m_parent);
    myDlg->exec();
}

};@

I think you could achieve it by the SLOT closeAllWindows(). In your main application when accepting closeEvent, just call closeAllWindows(), maybe that could work.

@void yourApplication::closeEvent(QCloseEvent *event)
{
closeAllWindows();
event->accept();
}@

Nevertheless take a look to "this documentation on closeEvent":http://qt-project.org/doc/qt-4.8/qcloseevent.html

Good luck!

I have a Factory to build and show this Dialogs... as you can see here:

@
#include "caixadialogo.h"
#include "singletonsession.h"

CaixaDialogo::CaixaDialogo(QObject parent) :
QObject(parent)
{
}
QMessageBox CaixaDialogo::getConfiguradoComSucesso(QString mensagem, QWidget parent)
{
QMessageBox msgBox = new QMessageBox( parent );
msgBox->setText( mensagem.toAscii() );
msgBox->setIcon(QMessageBox::Information);
return msgBox;
}
QMessageBox* CaixaDialogo::getErroAoConfigurar(QString mensagem, QWidget parent)
{
QMessageBox msgBox = new QMessageBox( parent );
msgBox->setText( mensagem.toAscii() );
msgBox->setIcon(QMessageBox::Warning);
return msgBox;
}
QMessageBox* CaixaDialogo::getMensagemSucesso(QString mensagem, QWidget parent)
{
QMessageBox msgBox = new QMessageBox( parent );
msgBox->setText( mensagem.toAscii() );
msgBox->setIcon(QMessageBox::Information);
return msgBox;
}
QMessageBox* CaixaDialogo::getMensagemErro(QString mensagem, QWidget parent)
{
QMessageBox msgBox = new QMessageBox( parent );
msgBox->setText( mensagem.toAscii() );
msgBox->setIcon(QMessageBox::Warning);
return msgBox;
}
QMessageBox* CaixaDialogo::getMensagemAviso(QString mensagem, QWidget parent)
{
QMessageBox msgBox = new QMessageBox( parent );
msgBox->setText( mensagem.toAscii() );
return msgBox;
}
@

This is stange. You should still be able to assign a parent. And if it's really impossible, then store pointers to all rouge QDialogs you have and destroy them on qApp->quit().