Qt multiple key combo event

Question

I\'m using Qt 4.6 and I\'d like to react to multi-key combos (e.g. Key_Q+Key_W) that are being held down. So when you hold down a key combo, the event should be called all t

Answer 1

You can add a pressed key to the set of pressed keys and remove from this set when the key is released. So you can add the pressed key to a QSet which is a class member :

QSet pressedKeys;

You can catch the key events in an event filter :

bool MyWidget::eventFilter(QObject * obj, QEvent * event)
{

    if(event->type()==QEvent::KeyPress) {

        pressedKeys += ((QKeyEvent*)event)->key();

        f( pressedKeys.contains(Qt::Key_D) && pressedKeys.contains(Qt::Key_W) )
        {
            // D and W are pressed
        }

    }
    else if(event->type()==QEvent::KeyRelease)
    {

        pressedKeys -= ((QKeyEvent*)event)->key();
    }


    return false;
}

Don't forget to install the event filter in the constructor:

this->installEventFilter(this);