Qt / C++ - Monitor specified input without focus

Question

I want to be able to press a specific Qt::Key at any time regardless of focus. For example, ctrl+shift+F activates a method that brings the window back into focus.

I've done google searches for how to monitor input without focus in qt but I can't find anything.

Answer 1

You can do this either by subclassing QApplication and overriding its event(QEvent *) method, or (more commonly) by calling qApp->installEventFilter(someObject), where (someObject) is some Qt object (whichever one is most convenient for you) whose eventFilter(QObject *, QEvent *) method you have overridden with your own implementation that watches for the appropriate QKeyEvent and does the appropriate action in response.

Answer 2

This feature is not implemented in Qt. You can use Qxt. Qxt is an extension library for Qt providing a suite of cross-platform utility classes to add functionality not readily available in Qt. It has Global Shortcut (hot keys) which detects key presses even if the application is minimized or hidden.

After compiling Qxt, link your application to it by adding these to your .pro :

CONFIG += qxt
QXT = core gui

And include QxtGlobalShortcut :

#include <QxtGlobalShortcut>

Example usage :

QxtGlobalShortcut* shortcut = new QxtGlobalShortcut(window);
connect(shortcut, SIGNAL(activated()), window, SLOT(toggleVisibility()));
shortcut->setShortcut(QKeySequence("Ctrl+Shift+F"));