Updating Existing Object in Firebase with Swift 3

Question

I've been having trouble saving an object pulled in from Firebase. I want to grab the value of 'cardAmount', add to it and save it. But it keeps giving me trouble about it not being ale to convert a number to a string. I think I might be hung up on modifying the data structure wrong, but I've been stuck on this for a little while - can anyone give me some guidance on how to edit a single Child Snapshot in Firebase as I need it?

let sevenDayOption = UIAlertAction(title: "Seven Day: $31", style: .default, handler: {
        (alert: UIAlertAction!) -> Void in
        let query = ref.queryOrdered(byChild: (FIRAuth.auth()!.currentUser?.uid)!)
        query.observeSingleEvent(of: .value, with: { (snapshot) in
            let cardAmount = snapshot.childSnapshot(forPath: "cardAmount").value as! Float
            let newAmount = cardAmount + 31
            let newAmountString = String(format:"%.2f", newAmount)
            snapshot.setValue(newAmountString, forKeyPath: snapshot.childSnapshot(forPath: "cardAmount").value as! String)
            print(snapshot.childSnapshot(forPath: "cardAmount").value as! Float) /*<---- Prints Optional(30.5)*/

        })
    })

I'm sure it's probably something simple, but it's also something that eludes me at the moment. Relatively new to Firebase and Swift so its been a bit of a challenge wrestling with it at times.

Thanks!

there is runTransactionBlock. Or you can use updateChildValues method — Wolverine
– Wolverine, Commented Nov 30, 2016 at 12:58
updateChildValues worked perfectly! Submitting answer. Thank you so much! — Studio Symposium
– Studio Symposium, Commented Nov 30, 2016 at 13:16

Studio Symposium · Accepted Answer · 2016-11-30 13:18:10Z

1

For those of you who come across this and have trouble in the future - the answer came from the updateChildValues method that Firebase offers:

let sevenDayOption = UIAlertAction(title: "Seven Day: $31", style: .default, handler: {
        (alert: UIAlertAction!) -> Void in
        let query = ref.queryOrdered(byChild: (FIRAuth.auth()!.currentUser?.uid)!)
        query.observeSingleEvent(of: .value, with: { (snapshot) in
            let cardAmount = snapshot.childSnapshot(forPath: "cardAmount").value as! Float
            let newAmount = cardAmount + 31
            let newAmountString = String(format:"%.2f", newAmount)
            ref.updateChildValues(["cardAmount":newAmountString])/*<------ CRITICAL*/
        })
    })

Thank you so much!

answered Nov 30, 2016 at 13:18

Studio Symposium

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Comments

SymbolixAU · Accepted Answer · 2017-09-06 10:09:38Z

0

Try this code

ref.child("yourKey").child("yourKey").updateChildValues(["cardAmount": yourNewCardAmount])

This worked for me. Hope will help someone...

edited Sep 6, 2017 at 10:09

SymbolixAU

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answered Nov 30, 2016 at 13:19

Human

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