Use variable inside Firebase snapshot function

Asked Mar 05 '17 at 18:53

Active Mar 05 '17 at 19:10

Viewed 52 times

This question is not duplciated because others don't work and are not exactly like mine. I want to set the value of this snapshot in the var averageMark. Like in this code:

func initAverageMark(completion: @escaping (Bool) -> ()) {

    let userRef = ref.child("users").child((user?.uid)!).child("mark")

    userRef.observeSingleEvent(of: .value, with: { (snapshot) -> Void in
        if let mark: Double = snapshot.value as? Double {
            self.averageMark = mark
        }
        print("res: \(self.averageMark)") // 1st print
        completion(true)

    }) { (error) in
        print(error.localizedDescription)
    }
    print("res: \(self.averageMark)") // 2nd print
}

My issue is that the variable get a value inside the snapshot function but is nil outside of this function. The first print is "2.0" (which is correct) and the second is nil.

The real trouble is that I alreay did soemthing like that without any problem...

How is it possible? We can only use the values inside the snapshot? Thanks

edited Mar 05 '17 at 19:10

asked Mar 05 '17 at 18:53

Paul Bénéteau

I added completion to force the task performing sync. – Paul Bénéteau Mar 05 '17 at 19:00
See also: http://stackoverflow.com/questions/25203556/returning-data-from-async-call-in-swift-function, http://stackoverflow.com/questions/17642535/return-value-for-function-inside-a-block – jscs Mar 05 '17 at 19:11
Not working... That's why i ask it again. – Paul Bénéteau Mar 05 '17 at 19:38
is this func in a viewController or its own struct/class? – Ro4ch Mar 05 '17 at 20:49
@Ro4ch This func is in its own class. I call it from a `viewController` – Paul Bénéteau Mar 05 '17 at 21:44
I had something similar. I needed access to an array so I created an array in my viewController that pointed to the array in the fetch function that was in the enclosure. So it was like this myVCArray = fetch.fetchArray. – Ro4ch Mar 06 '17 at 08:00

Use variable inside Firebase snapshot function

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