Qfyilyi

I am using Swift to retrieve data from my Firebase database. When the user first logs in, I'd like to save the 'places' from my Firebase snapshot as a UserDefault.

static func getAllPlaces(){



    databaseRef = Database.database().reference()



    databaseRef.database.reference().child("places").observe(.childAdded) { (snapshot: DataSnapshot) in



        if let value = snapshot.value as? NSDictionary {



            let place = Place()



            let id = value["id"] as? String ?? "ID not found"

            let title = value["title"] as? String ?? "Title not found"

            let type = value["type"] as? String ?? ""



            place.id = id

            place.title = title

            place.type = type



            DispatchQueue.global().async {

                // Something here to append place data to UserDefaults?

                places.append(place) // appends to NSObject for later use

            }

        }



    }

}

The current code works fine - I just need to add something to get it stored so I can grab it later.

Bonus question: I am storing a good few hundred snapshots in the Firebase database. The reason I want to store them on the device is so that the user doesn't have to keep downloading the data. Is this a good idea? Would it take up a lot of memory?

Any help would be appreciated.

One way to save custom classes/data to UserDefaults is to encode them like this:

let encodedData: Data = NSKeyedArchiver.archivedData(withRootObject: place)

UserDefaults.standard.set(encodedData, forKey: "place")

UserDefaults.standard.synchronize()

Then you can decode it like this:

if UserDefaults.standard.object(forKey: "place") != nil{

    let decodedData = UserDefaults.standard.object(forKey: "place") as! Data

    let decodedPlace = NSKeyedUnarchiver.unarchiveObject(with: decodedData) as! Place

}

Updated for swift 4 and iOS 12:

do {

    let encodedData: Data = try NSKeyedArchiver.archivedData(withRootObject: place, requiringSecureCoding: false)

    UserDefaults.standard.set(encodedData, forKey: "place")

    UserDefaults.standard.synchronize()

} catch {

        //Handle Error

}



do {

    if UserDefaults.standard.object(forKey: "place") != nil{

        let decodedData = UserDefaults.standard.object(forKey: "place") as! Data

        if let decodedPlace = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(decodedData) as? Place {

             //Do Something with decodedPlace

        }

    }

}

catch {

        //Handle Error

}