class CMainWindow : public QMainWindow
{
    Q_OBJECT
.......
private:
    QThread mThread;
.......
};

CMainWindow::CMainWindow(QWidget *parent)
	: QMainWindow(parent), mpUi(new Ui::CMainWindow)
{
.......
    mThread.start();

    CSomeClass *s = new CSomeClass;
    connect(&mThread, SIGNAL(finished()), s, SLOT(deleteLater()));

    s->moveToThread(&mThread);
.......
}

CMainWindow::~CMainWindow()
{
	mThread.quit();
	mThread.wait();
}

class CMainWindow : public QMainWindow
{
    Q_OBJECT
.......
private:
    QThread mThread;
    CSomeClass *mpS;
.......
};

CMainWindow::CMainWindow(QWidget *parent)
	: QMainWindow(parent), mpUi(new Ui::CMainWindow)
{
.......
    connect(&mThread, SIGNAL(finished()), this, SLOT(deleteListener()));
.......
}

void CMainWindow::closeEvent(QCloseEvent * e)
{
	on_actConnectToServer_toggled(false);
	e->accept();
}

void CMainWindow::on_actConnectToServer_toggled( bool v )
{
	if(v) {
		mpS = new CSomeClass;
		mpS->moveToThread(&mThread);

		mThread.start();

	} else {
		mThread.quit();
		mThread.wait();
	}
}

void CMainWindow::deleteListener()
{
	delete mpS;
}