Newbee: eventFilter on QCoreApplication... how?

[obiwanjacobi]

Hi,

I'm very new to Qt and am trying to write a console application that will intercept key strokes (when it has the focus) and send these over USB to an external hardware device.

After reading some of the docs I tried to implement an eventFilter and add that to the application using installEventFilter.

class KeyEventFilter : public QObject {
	Q_OBJECT

public:
	KeyEventFilter(QObject * parent = Q_NULLPTR);
	~KeyEventFilter();

	bool eventFilter(QObject* o, QEvent* e) override;
};

bool KeyEventFilter::eventFilter(QObject* o, QEvent* e)
{
	qDebug() << "Type:" << e->type();

	if (e->type() == QEvent::KeyPress) {
		QKeyEvent* keyEvent = static_cast<QKeyEvent*>(e);
		qDebug() << "Key:" << keyEvent->key();
	}

	return QObject::eventFilter(o, e);
}

int main(int argc, char *argv[])
{
	QCoreApplication app(argc, argv);

	auto filter = new KeyEventFilter();
	app.installEventFilter(filter);

	return app.exec();
}

qDebug() traces or any breakpoints do not seem to get called.

The I have tried to derive from QCoreApplication and override the notify or eventFilter methods.

class Program : public QCoreApplication
{
public:
	Program(int argc, char *argv[]) : QCoreApplication(argc, argv) {}

	bool notify(QObject* o, QEvent* e) override {
		qDebug() << "Type:" << e->type();
		return QCoreApplication::notify(o, e);
	}

	bool eventFilter(QObject* o, QEvent* e) override {
		qDebug() << "Type:" << e->type();
		return QCoreApplication::eventFilter(o, e);
	}
};

These methods also do not get called. I suspect there may be a fundamental problem but I can't see what it could be.
Marc

Windows 8.1, Visual Studio 2015 Community (update3), Qt5.7 => x64/Debug

[jsulm]

@obiwanjacobi If it is a console application then you need to use std::cin. You will not have any key-events in a pure console application, those are for UI widgets.