Repeat calls to "connect" for QShortcut not working

Trayon

I made a function to create QShortcuts from a pair consisting of a key and a function to apply when that key is pressed. This way, I can simply declare a vector of pairs and lambda functions to make a clean entry for what I want done. The problem is, my first test works, but my second doesn't. I've recreated a simulation of what I'm trying to see if you guys can spot the problem.

    auto createShortCut3 = [parent](pair<
            QKeySequence, function<void()>
            > kfPair) {
        QShortcut *keyShortcut = new QShortcut(parent);
            keyShortcut->setKey(kfPair.first);
            QObject::connect(keyShortcut, &QShortcut::activated, kfPair.second);
    };

    createShortCut3(std::make_pair(Qt::Key_Alt, [this]() {
            qDebug() << "KEY ALT";})); // Doesn't work

    createShortCut3(std::make_pair(Qt::Key_Q, [this]() {
            qDebug() << "KEY Q";})); // Works

hskoglund

@Trayon I think it fails because you're trying to use the single Alt key as a shortcut (it's usually reserved by Windows).
So if you try instead with another letter, say Qt::Key_X, such a repeated call to "connect" should work just fine.

Trayon

Odd, that somehow worked for that particular instance. I'm actually using Linux mint, but it seems it has the same behavior. Where can I read about these particular caveats?

hskoglund

Hi, usually you can create a shortcut for the Alt key combined with some digit or letter (even on Windows :-)

To catch an standalone Alt key being pressed by itsefl (similarly for the Win, Ctrl or Shift keys) you need to go more lowlevel and listen to keypresses.

Trayon

I see. I was using key presses before, but there was a focus error, so I switched over. Thanks for the advice!