No keyboard events with QCoreApplication

[Cruz]

Hi!

I'm running a simple command line application based on QCoreApplication and for some reason I am not receiving keyboard inputs. When in run this program in the command line on Linux using ./Application, I can see the keys that I press on the keyboard and but there is no reaction from the keyPressEvent. Can anyone point out where my mistake is?

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    Application w;
    a.installEventFilter(&w);
    return a.exec();
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    Application w;
    a.installEventFilter(&w);
    return a.exec();
}

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class Application : public QObject
{
    Q_OBJECT
 
public:
    Application(QObject *parent = 0);
    ~Application();
 
protected:
    void keyPressEvent(QKeyEvent *event);
};
 
void Application::keyPressEvent(QKeyEvent *event)
{
    qDebug() << "keyPressEvent event occured" << event; // This is never printed.
}

class Application : public QObject
{
    Q_OBJECT

public:
    Application(QObject *parent = 0);
    ~Application();

protected:
    void keyPressEvent(QKeyEvent *event);
};

void Application::keyPressEvent(QKeyEvent *event)
{
    qDebug() << "keyPressEvent event occured" << event; // This is never printed.
}

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[d_stranz]

You need to add the protected method QObject::eventFilter() to your Application class instead of the keyPressEvent):

class Application : public QObject
{
    Q_OBJECT
 
public:
    Application(QObject *parent = 0);
    ~Application();
 
protected:
    bool eventFilter( QObject * pObj, QEvent * pEvent ) override;
};
 
bool Application::eventFilter( QObject * pObj, QEvent * pEvent )
{
    if ( pEvent->type() == QEvent::KeyPress )
    {
        // got a key press
        return true;
    }
    else
        return QObject::eventFilter( pObj, pEvent );
}

class Application : public QObject
{
    Q_OBJECT
 
public:
    Application(QObject *parent = 0);
    ~Application();
 
protected:
    bool eventFilter( QObject * pObj, QEvent * pEvent ) override;
};

bool Application::eventFilter( QObject * pObj, QEvent * pEvent )
{
    if ( pEvent->type() == QEvent::KeyPress )
    {
        // got a key press
        return true;
    }
    else
        return QObject::eventFilter( pObj, pEvent );
}

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Because your current Application class implementation does not define this method, the base class QObject's method is called instead.