在Swift for OSX的子类中管理事件处理

Question

I'm trying to implement a subclass of an NSSlider, which is supposed to handle modifiers keys events. I've put this override func in the class:

    override func flagsChanged(theEvent: NSEvent) {
    if (theEvent.modifierFlags.rawValue & NSEventModifierFlags.DeviceIndependentModifierFlagsMask.rawValue) == NSEventModifierFlags.AlternateKeyMask.rawValue {
        optionKeyPressed = true
        Swift.print("OptionKey is pressed")
    } else {
        optionKeyPressed = false
    }
}

And an initializer in:

    override init(frame: NSRect) {
        super.init(frame: frame)
    NSEvent.addLocalMonitorForEventsMatchingMask(.FlagsChangedMask) { (theEvent) -> NSEvent? in
        self.flagsChanged(theEvent)
        return theEvent
    }

Unfortunately, when I try to use my subclass in a storyboard, nothing happen: the init function is never called.

Pretty much a newbie in all these things, some guidance would be nice! Many thanks,

Josh

Answer 1

You also need to implement the initWithCoder: initialiser, because when you use a class in a Storyboard, that initialiser is called:

required init?(coder: NSCoder) {
    super.init(coder: coder)
    NSEvent.addLocalMonitorForEventsMatchingMask(.FlagsChangedMask) { (theEvent) -> NSEvent? in
        self.flagsChanged(theEvent)
        return theEvent
    }
}