How to encode [CLLocation] properly in swift? - swift3

Question

I am doing an application which need to store the user's data in local. I read the documentation in Apple website, it covers part of the info in how to encode basic type, such as String and Int. However, when I try to encode with the [CLLocation]type, it failed. I am asking if some expert can give me any hint on how to encode such type in Swift?
Here is my code about the Model class.
import Foundation
import UIKit
import CoreLocation
import os.log
import CoreData
//route model
//store the model in the local database.
//change all the [CLLocations] to become the String inorder to store it in local.???? not willing
class Route: NSObject, NSCoding {
//MARK: Properties
var name :String
var area : String
var image: UIImage?
var date : DispatchTime
var routePoints = [CLLocation]()
var rating: Int
//MARK: Achieving paths
//static properties, belong to the
static let DocumentsDirectory = FileManager().urls(for: .documentDirectory, in: .userDomainMask).first!
static let ArchiveURL = DocumentsDirectory.appendingPathComponent("Routes")
//MARK: NSCoding
func encode(with aCoder: NSCoder) {
aCoder.encode(name, forKey: PropertyKey.name)
aCoder.encode(image, forKey: PropertyKey.image)
aCoder.encode(date, forKey: PropertyKey.date)
aCoder.encode(area, forKey: PropertyKey.area)
//unable to encode the [cllocation]
aCoder.encode(routePoints, forKey: PropertyKey.routePoints)
aCoder.encode(rating, forKey: PropertyKey.rating)
}
//should also added in the locations as one of the variable.
init?(Name: String, Area: String, Date: DispatchTime, Image: UIImage?, RoutePoints: [CLLocation], Rating: Int) {
guard (Rating >= 0) && (Rating <= 5) else {
return nil
}
self.name = Name
self.area = Area
self.image = Image
self.date = Date
self.routePoints = RoutePoints
self.rating = Rating
}
required convenience init?(coder aDecoder: NSCoder){
//this is the necessary property
//these are optional properties
let rating = aDecoder.decodeInteger(forKey: PropertyKey.rating)
guard let date = aDecoder.decodeObject(forKey: PropertyKey.date) as? DispatchTime,
let name = aDecoder.decodeObject(forKey: PropertyKey.name) as? String,
let image = aDecoder.decodeObject(forKey: PropertyKey.image) as? UIImage,
let area = aDecoder.decodeObject(forKey: PropertyKey.area) as? String,
let routePoints = aDecoder.decodeObject(forKey: PropertyKey.routePoints) as? [CLLocation] else{
print("Unable to decode")
return nil
}
self.init(Name: name, Area: area, Date: date, Image: image, RoutePoints: routePoints, Rating: rating)
}
//MARK: Types
struct PropertyKey {
static let name = "name"
static let image = "image"
static let date = "date"
static let area = "area"
static let rating = "rating"
static let routePoints = "routePoints"
}
}
Best wishes

Answer 1

The reason is that CLLocation can't be stored with NSCoder. You could implement a simple coder / decoder using a swift map for this type of value to basically store the locations in a dictionary.
let p1 = CLLocation(latitude: 1, longitude: 1)
let p2 = CLLocation(latitude: 2, longitude:2)
var locations = [p1, p2]
let codedArray = locations.map{ ["lat":$0.coordinate.latitude, "long":$0.coordinate.longitude] }
let decodedArray = codedArray.map{ CLLocation(latitude:$0["lat"]!, longitude:$0["long"]!) }