#include <QtCore>
#include <QtWidgets>


class MainWindow : public QMainWindow
{
public:
    MainWindow();
    
protected:
    void keyPressEvent(QKeyEvent *event) override;
    bool eventFilter(QObject *obj, QEvent *ev) override;

private:
    QTextEdit *textEdit;
};

MainWindow::MainWindow()
{
    textEdit = new QTextEdit(this);
    setCentralWidget(textEdit);

    //textEdit->installEventFilter(this);
    installEventFilter(this);
    grabKeyboard();
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
        if (event->type() == QEvent::KeyPress) {
            QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
            qDebug() << "key press" << keyEvent->key();
            return false;
        else if (event->type() == QEvent::KeyRelease) {
            QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
            qDebug() << "key release" << keyEvent->key();
            return false;
        } else {
            return false;
        }
}

void MainWindow::keyPressEvent(QKeyEvent *event)
{
    qDebug("MainWindow keyPressEvent %d", event->key());
    
    QMainWindow::keyPressEvent(event);
}