connect(mainArea,SIGNAL(subWindowActivated(QMdiSubWindow*)), this, SLOT(changeFocus(QMdiSubWindow*)));
...
void TestCreator::changeFocus(QMdiSubWindow *wid)
{
    Test *w = qobject_cast<Test *>(wid);
    if(!w)
        return;
    pOpenTest = w;
    t_line[0].setText(pOpenTest->windowTitle());
}

Test *w = qobject_cast<Test *>(wid->widget());

void MainWindow::on_action_goods_triggered()
{
    goods_form *E_F = new goods_form();
    E_F->setAttribute(Qt::WA_DeleteOnClose);
    QMdiSubWindow *widg = new QMdiSubWindow(this);
    widg->setAttribute(Qt::WA_DeleteOnClose);
    QObject::connect(E_F, SIGNAL(signal_closing()), widg, SLOT(close()), Qt::AutoConnection);
    widg->setWidget(E_F);
    widg->setWindowTitle(tr("Список товаров"));
    widg->setWindowIcon(QIcon (":/icons/goods.ico"));
    widg->setGeometry(QRect(10, 10, 1100, 500));
    add_new_window(widg);
}

void MainWindow::add_new_window(QMdiSubWindow *p_sub)
{
    QMdiSubWindow *sub = ui->mdiArea->addSubWindow(p_sub);
    sub->setAttribute(Qt::WA_DeleteOnClose);
    sub->show();
}

void TestCreator::newTest()
{
    Test* pTest = new Test(this);
    pTest->setAttribute(Qt::WA_DeleteOnClose);
    QMdiSubWindow *wid = new QMdiSubWindow(this);
    wid->setAttribute(Qt::WA_DeleteOnClose);
    connect(pTest, SIGNAL(destroyed()), wid, SLOT(close()), Qt::AutoConnection);
    wid->setWidget(pTest);
    wid->setWindowTitle(tr("Unnamed Test"));
    createNewTest(wid);
    t_line[0].setText(pOpenTest->windowTitle());
}

void TestCreator::createNewTest(QMdiSubWindow *p_sub)
{
    QMdiSubWindow* sub = mainArea->addSubWindow(p_sub);
    p_sub->setAttribute(Qt::WA_DeleteOnClose);
    p_sub->show();
}

Цитата(grio @ 13.5.2010, 18:07)

if(mainArea->subWindowList().isEmpty())
        return;