NSEvent: test for only one modfierkey

Question

Ok, I understand how to determine from an NSEvent if a modifierkey is pressed :

if ([theEvent modifierFlags] & NSAlternateKeyMask) {
        // The Option/Alt key was pressed
    }

But this also captures the optionkey and another modifierkey at the same time, eg Option+Shift, or any combination with the optionkey.

How do I test for only the optionkey and nothing else?

score 4 · Accepted Answer · answered Feb 04 '12 at 15:49

4

Like this:

const NSUInteger kNotAlt = NSAlphaShiftKeyMask | NSShiftKeyMask | NSControlKeyMask | NSCommandKeyMask;
NSUInteger modFlags = [theEvent modifierFlags];
if (((modFlags & NSAlternateKeyMask) != 0) &&
    ((modFlags & kNotAlt) == 0))
{
    // Only alt was pressed
}

answered Feb 04 '12 at 15:49

user1118321

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4
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Thanks - I'll make this into a category for NSEvent and add similar methods for other keys as well. – koen Feb 04 '12 at 19:17
Great! If this solved your problem, please click the green checkbox to the left! – user1118321 Feb 04 '12 at 21:29

score 4 · Answer 2 · answered Feb 05 '12 at 00:06

4

You can also try

NSUInteger modFlags = [theEvent modifierFlags];
if ((modFlags & NSCommandKeyMask) && !(modFlags & ~NSCommandKeyMask))
{
    // Only alt was pressed
}

answered Feb 05 '12 at 00:06

Tony

36,591
10
48
83

1

Thanks everyone. In the meantime I also found another, more general solution. I hope the formatting is ok.
`NSUInteger modifiers = [event modifierFlags] & (NSCommandKeyMask | NSAlternateKeyMask | NSShiftKeyMask | NSControlKeyMask);
if (modifiers == NSAlternateKeyMask)
{
// only alt was pressed
}` – koen Feb 05 '12 at 03:07

NSEvent: test for only one modfierkey

2 Answers2