keyPressEvent no reaction

Question

I am writing on QT. OpenGL is connected, work properly, but the events and keyPressEvent mousePressEvent not respond to keystrokes.

class MainWindow : public QGLWidget
{
    Q_OBJECT
    protected:
        void initializeGL(); // Метод для инициализирования opengl
        void resizeGL(int nWidth, int nHeight); // Метод вызываемый после каждого изменения размера окна
        void paintGL(); // Метод для вывода изображения на экран
        void paintSun();
        void mousePressEvent(QMouseEvent *mouse);
        void keyPressEvent(QKeyEvent *ke);
public:
    MainWindow(int x, int y,QWidget *parent = 0);
    ~MainWindow();
};

void MainWindow::keyPressEvent(QKeyEvent *ke)
{
    switch (ke->key())
    {
          case Qt::Key_Space://NO REACTION
                View += 1;
                glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
                paintPlanet();
                break;
    }
    updateGL();
}

Answer 1

Make sure that the MainWindow accepts Focus by setting

QWidget::setFocusPolicy()

Also you should call the base implementation of QWidget::keyPressEvent as stated here. Is there another Widget which has the focus and does not pass the KeyEvent?