MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QGraphicsView *view=new QGraphicsView();
    this->setCentralWidget(view);
    QGraphicsScene *scene=new QGraphicsScene();
    view->setScene(scene);
    QLineEdit *edit=new QLineEdit();
    scene->addWidget(edit);
}