I'm trying to write an array of objects using NSKeyedArchiver.
Here some parts from my code:
EventStore.swift - holding the event array:
class EventStore{
private var events: [EventItem] = [EventItem]()
static let sharedStore = EventStore()
private init() {
}
static func getEventFile() -> URL{
let directory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let file = directory.appendingPathComponent("events.bin")
return file
}
func addEvent(withEvent event:EventItem){
events.append(event)
}
func getEvents()->[EventItem]{
return events
}
}
No the eventItem where I implemented NSCoding:
class EventItem: NSObject, NSCoding {
private var id:Int
private var timestamp:Int64
//Object initialization
init(withId id:Int,withTimestamp timestamp:Int64) {
self.id = id
self.timestamp = timestamp
}
required convenience init?(coder: NSCoder) {
//get value from stored key if exists
guard let id = coder.decodeObject(forKey: "id") as? Int,
let timestamp = coder.decodeObject(forKey: "timestamp") as? Int64
//exit init after decoding if a value is missing
else {
NSLog("Unable to decode event")
return nil
}
self.init(withId:id,withTimestamp:timestamp)
}
func getId()->Int{
return id
}
func getTimestamp()->Int64{
return timestamp
}
//encode values to keys
func encode(with aCoder: NSCoder) {
NSLog("Encoding event")
aCoder.encode(id, forKey: "id")
aCoder.encode(timestamp, forKey: "timestamp")
}
}
Finally when the user tape on a button I'm adding an event into the array and saving it:
var eventStore = EventStore.sharedStore
@IBAction func TakeAction() {
//generate new event
let timestamp = Int64(NSDate().timeIntervalSince1970 * 1000)
let newEvent = EventItem(withId: eventStore.eventCount(), withTimestamp: timestamp)
eventStore.addEvent(withEvent: newEvent)
saveEvents()
//refresh ui
updateTakeText()
}
func saveEvents(){
do{
let data = try NSKeyedArchiver.archivedData(withRootObject: eventStore.getEvents(), requiringSecureCoding: false)
NSLog("Data being written : \(data)")
try data.write(to: EventStore.getEventFile())
NSLog("Write events to file :\(EventStore.getEventFile())")
}catch{
NSLog(error.localizedDescription)
}
}
func loadEvents() {
do{
let data = try Data(contentsOf: EventStore.getEventFile())
NSLog("Data loaded from file path: \(data)")
//try get data else return empty array
let events = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as? [EventItem] ?? [EventItem]()
NSLog("Events retrived from file: \(events.count)")
eventStore.setEvents(withEvents:events)
}catch{
NSLog(error.localizedDescription)
}
}
I added a lot of debug and it seems that the encoding and file write are working fine but the decoding fail. It always get nil values.
Any clue?
Thanks in advance
