Swift / NSMutableDisctionary init /如何使值可选

Question

To store data into my firebase I'm using the following Code:

class NewEventDate {

    private let firebase = FIRDatabase.database().reference().child("eventDates")
    let eventDictionary: NSMutableDictionary

    init (date: String, free: String, club: String) {

        eventDictionary = NSMutableDictionary(objects: [date, free, club], forKeys: ["date", "free", "club"])
    }

    func saveEventDate(backendlessUserObjectID: String, item: NSMutableDictionary) {

        let reference = firebase.child(backendlessUserObjectID)
        reference.setValue(item) { (error, ref) -> Void in
            if error != nil {
                SpeedLog.print("\(error)")
            }
        }
    }
}

Called by:

func saveDatesLoop() {

    for date in calendarView.selectedDates {
        saveDateToFirebase(formatter.stringFromDate(date), free: "true", club: "11er")
    }
}

func saveDateToFirebase(date: String, free: String, club: String) {

    var newEvent = NewEventDate?()
    newEvent = NewEventDate(date: date, free: free, club: club)
    newEvent?.saveEventDate(backendless.userService.currentUser.objectId, item: newEvent!.eventDictionary)
}

I want free and club to be optional, so I can set them nil like that: saveDateToFirebase(formatter.stringFromDate(date), free: nil, club: nil)

What's the best practice to realize that? Help is very appreciated.

PS: free: "true", club: "11er" is hard coded to test.

PPS: I've tried to set init (date: String, free: String?, club: String?) , but Xcode forces me to unwrap them later on...

Answer 1

I was able to make them optional (to be able to put them nil) with a little workaround:

init (date: String, free: String?, club: String?, eventText: String?) {
    var localFree = ""
    var localClub = ""
    var localEventText = ""

    if let tempFree = free {
        localFree = tempFree
    }
    if let tempClub = club {
        localClub = tempClub
    }
    if let tempEventText = eventText {
        localEventText = tempEventText
    }

    eventDictionary = NSMutableDictionary(objects: [date, localFree, localClub, localEventText], forKeys: ["date", "free", "club", "eventText"])

}

Now I can call it like this:

func saveDateToFirebase(date: String, free: String?, club: String?, eventText: String?) {

    var newEvent = NewEventDate?()
    newEvent = NewEventDate(date: date, free: free, club: club, eventText: eventText)
    newEvent?.saveEventDate(backendless.userService.currentUser.objectId, date: date, item: newEvent!.eventDictionary)
}

And finally make them nil if I want too:

saveDateToFirebase(NSDate(), free: nil, club: nil, eventText: nil)