How to check if Option key is down when user clicks a NSButton

Question

I have a few checkboxes along with textfields on a NSPanel that opens to get user parameters. As an option, I'd like the user to be able to set/unset all the checkboxes on the panel by holding the option key when they press any of the checkboxes.

I'm not sure where/how to check what the key board is doing when the user clicks the button.

Answer 1

check [NSEvent modifierFlags]...

if ([NSEvent modifierFlags ] & NSAlternateKeyMask)
{
    //do something
}

Answer 2

Just my 2c, a Swift 3 version:

if NSEvent.modifierFlags().contains(NSEventModifierFlags.command) {
    print("Bingo")
}

One can see the rest of the flags in the documentation for NSEventModifierFlags.

Answer 3

Update: NSAlternateKeyMask is now deprecated. Use NSEventModifierFlagOption instead.

See NSEventModifierFlags for a complete overview about all modifier flags.