从X11接收到抓取的钥匙时，如何防止窗口失去焦点

Question

My window calls hide() when a QEvent::FocusOut is received. Simultaniously I want its visibility to be toggled if a hotkey is pressed. Now I have the following problem: Pressing the hotkey, registered with XGrabKex(...) seems to steel the focus of my app. Resulting in an unwanted behaviour. If my app is visible the hotkeyevent steels focus, which results in a QEvent::FocusOut , which hides my app, and after that the hotkey is received which toggles visibility (shows) my app. Ie my app does not hide when pressing the hotkey.

Is there a way to tell the x window system to not steel the focus when a grabbed key is pressed? Or are there other possible solutions to this problem?

Answer 1

A couple of different methods.

1. Use XQueryKeymap to see which keys are pressed. For instance, when you get a FocusOut event, call XQueryKeymap and see if your hotkey is pressed. If it is not, hide the window; if it is, don't hide it and wait for the hotkey event.
2. Delay hiding on FocusOut by 100 or so milliseconds. Cancel hiding if you either get the hot key or get your focus back during this time interval.

Look also here for useful info.

Answer 2

Finally got it to work in a "proper" way:

bool MainWidget::nativeEvent(const QByteArray &eventType, void *message, long *)
{
#ifdef Q_OS_LINUX
    if (eventType == "xcb_generic_event_t")
    {
        xcb_generic_event_t* event = static_cast<xcb_generic_event_t *>(message);
        switch (event->response_type & 127)
        {
        case XCB_FOCUS_OUT: {
            xcb_focus_out_event_t *fe = (xcb_focus_out_event_t *)event;
            if ((fe->mode==XCB_NOTIFY_MODE_GRAB && fe->detail==XCB_NOTIFY_DETAIL_NONLINEAR)
                    || (fe->mode==XCB_NOTIFY_MODE_NORMAL && fe->detail==XCB_NOTIFY_DETAIL_NONLINEAR ))
                hide();
            break;
        }
        }
    }
#endif
return false;
}