eventFilter: catch both Control and Shift modifiers

[LucaDanieli]

Hello,

I am overriding an eventFilter, and I am trying to catch both Shift and Control modifiers.
I am unfortunately unable to get the work together.

I tried both

QKeyEvent *key_event = static_cast<QKeyEvent*>(event);
if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))
{
...
}

QKeyEvent *key_event = static_cast<QKeyEvent*>(event);
if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))
{
...
}

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and

Qt::KeyboardModifiers keyMod = QApplication::keyboardModifiers ();
bool isSHIFT = keyMod.testFlag(Qt::ShiftModifier);
bool isCTRL = keyMod.testFlag(Qt::ControlModifier);
 
if (isSHIFT && isCTRL)
{
...
}

Qt::KeyboardModifiers keyMod = QApplication::keyboardModifiers ();
bool isSHIFT = keyMod.testFlag(Qt::ShiftModifier);
bool isCTRL = keyMod.testFlag(Qt::ControlModifier);
	
if (isSHIFT && isCTRL)
{
...
}

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Does someone know how to do it?

Luca

[anda_skoa]

Your first snippet looks ok to me, but maybe try to check each separately?

if ((event->modifiers() & Qt::ShiftModifier) != 0 && (event->modifiers() & Qt::ControlModifier) != 0)

if ((event->modifiers() & Qt::ShiftModifier) != 0 && (event->modifiers() & Qt::ControlModifier) != 0)

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Cheers,
_

[LucaDanieli]

Hi anda_skoa,

thanks for your help. Actually it doesn't work.

With this:

else if (key_event->key() == Qt::Key_U)
     if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))

else if (key_event->key() == Qt::Key_U)
     if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))

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it seems that Shift+U and Ctrl+U work separately.
With your solution instead:

if ((key_event->modifiers() & Qt::ShiftModifier) != 0 && (key_event->modifiers() & Qt::ControlModifier) != 0)

if ((key_event->modifiers() & Qt::ShiftModifier) != 0 && (key_event->modifiers() & Qt::ControlModifier) != 0)

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neither separate shortcuts work, nor together.

The fact is that I am trying to override the default Ctrl+Shift+U unicode Linux's shortcut. Is it possible?

[d_stranz]

The fact is that I am trying to override the default Ctrl+Shift+U unicode Linux's shortcut.

So does this code work (or not) for -other- non-system Ctrl-Shift-something combinations? Or just not work at all for anything?

[anda_skoa]

With your solution instead:

if ((key_event->modifiers() & Qt::ShiftModifier) != 0 && (key_event->modifiers() & Qt::ControlModifier) != 0)

if ((key_event->modifiers() & Qt::ShiftModifier) != 0 && (key_event->modifiers() & Qt::ControlModifier) != 0)

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neither separate shortcuts work, nor together.

Maybe your event filter returns true and filters the event before it gets to the actual shortcut handler?

The code above is just a check for both modifiers being present, it doesn't do anything.

Cheers,
_

[LucaDanieli]

Difficult to say.
I would say that it doesn't work at all.

I try with Qt::Key_9

else if (key_event->key() == Qt::Key_9)
            if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))
            {
                lookupReferences();
                event->ignore();
                return true;
            }

else if (key_event->key() == Qt::Key_9)
            if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))
            {
                lookupReferences();
                event->ignore();
                return true;
            }

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Shift+9 = ")" [Italian Keyboard]
Ctrl+9 = works
Ctrl+Shift+9 = ")"

From this, I would say that "|" means "or".

if ((key_event->modifiers() & Qt::ShiftModifier) != 0 && (key_event->modifiers() & Qt::ControlModifier) != 0)

if ((key_event->modifiers() & Qt::ShiftModifier) != 0 && (key_event->modifiers() & Qt::ControlModifier) != 0)

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Ctrl+Shift+9 = ")"
Ctrl+9 = nothing
Shift+9 = ")"

but

else if (key_event->key() == Qt::Key_U)
            if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))

else if (key_event->key() == Qt::Key_U)
            if (key_event->modifiers() & (Qt::ShiftModifier | Qt::ControlModifier))

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Shift+U = works
Ctrl+U = works


There is something weird here.
Later I will try more combinations

[LucaDanieli]

Yes, I checked again.
It works exactly as reported above.

I really don't understand this behaviour. "Shift+9" and "Shift+U" respond differently, and generally I can't trig Ctrl+Shift+Key, but only Ctrl+Key or Shift+Key.

[anda_skoa]

I assume you have checked that without any specific key?
E.g. just checked for both modifiers and then print the key whatever it is?

Did you install the event filter on a specific widget or on the application object?

Cheers,
_