class MyLineEdit : public QLineEdit
{
public:
    MyLineEdit() :QLineEdit("LineEdit") {}
    ~MyLineEdit() {}

    void keyPressEvent(QKeyEvent *e) {
        qDebug() << e;
        QLineEdit::keyPressEvent(e);
    }
    void keyReleaseEvent(QKeyEvent *e) {
        qDebug() << e;
        QLineEdit::keyReleaseEvent(e);
    }
};

int main(int argc, char **argv) {
    QApplication app(argc, argv);

    QWidget w;
    QLayout *layout = new QVBoxLayout;
    w.setLayout(layout);

    MyLineEdit *le = new MyLineEdit;
    layout->addWidget(le);

    w.show();
    return app.exec();
}