I archive object to data and save it to disk success by NSKeyedArchiver, but when I get data from NSKeyedUnarchiver, I can't cast it to type Object. I try to do it in many ways, but none of them success. I hope you can help me to solve this problem.. here is my code:
class Person:
class Person: NSObject, NSCoding {
func encode(with coder: NSCoder) {
coder.encode(firstName, forKey: "fisrtName")
coder.encode(lastName, forKey: "lastName")
coder.encode(age, forKey: "age")
}
required convenience init?(coder: NSCoder) {
guard let firstName = coder.decodeObject(forKey: "firstName") as? String,
let lastName = coder.decodeObject(forKey: "lastName") as? String else {
return nil
}
let age = coder.decodeInteger(forKey: "age")
self.init(firstname: firstName, lastName: lastName, age: age)
}
let firstName: String
let lastName: String
let age: Int
init(firstname: String, lastName: String, age: Int) {
self.firstName = firstname
self.lastName = lastName
self.age = age
}
}
Save data to disk:
let tuan = Person(firstname: "Tuan", lastName: "Hoang", age: 21)
let directoryPath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let path = directoryPath.first!.appendingPathComponent("PersonData")
let savePath = path.appendingPathComponent("data.plist")
do {
try FileManager.default.createDirectory(at: path, withIntermediateDirectories: true, attributes: nil)
let data = try! NSKeyedArchiver.archivedData(withRootObject: tuan, requiringSecureCoding: false)
do {
try data.write(to: savePath)
print("Save data success")
} catch {
print("Cant save data to path + \(error.localizedDescription)")
}
} catch {
print("Cant not create directory + \(error.localizedDescription)")
}
Load data:
do {
let savedData = try Data.init(contentsOf: savePath)
print("Get data success")
guard let data = try? NSKeyedUnarchiver.unarchivedObject(ofClass: Person.self, from: savedData) else {
print("Cant cast data")
return
}
print(data?.firstName)
} catch {
print("Cant get saved data ")
}
your error is here:
coder.encode(firstName, forKey: "fisrtName")
typo -> firstName
Related
I'm having a heck of a time trying to figure out how to store an array of my custom struct in UserDefaults.
Here is my code:
struct DomainSchema: Codable {
var domain: String
var schema: String
}
var domainSchemas: [DomainSchema] {
get {
if UserDefaults.standard.object(forKey: "domainSchemas") != nil {
let data = UserDefaults.standard.value(forKey: "domainSchemas") as! Data
let domainSchema = try? PropertyListDecoder().decode(DomainSchema.self, from: data)
return domainSchema!
}
return nil
}
set {
UserDefaults.standard.set(try? PropertyListEncoder().encode(newValue), forKey: "domainSchemas")
}
}
struct SettingsView: View {
var body: some View {
VStack {
ForEach(domainSchemas, id: \.domain) { domainSchema in
HStack {
Text(domainSchema.domain)
Text(domainSchema.schema)
}
}
// clear history button
}
.onAppear {
if (domainSchemas.isEmpty) {
domainSchemas.append(DomainSchema(domain: "reddit.com", schema: "apollo://"))
}
}
}
}
It is giving me these errors:
Cannot convert return expression of type 'DomainSchema' to return type '[DomainSchema]'
'nil' is incompatible with return type '[DomainSchema]'
I'm not really sure how to get an array of the objects instead of just a single object, or how to resolve the nil incompatibility error...
If you really want to persist your data using UserDefaults the easiest way would be to use a class and conform it to NSCoding. Regarding your global var domainSchemas I would recommend using a singleton or extend UserDefaults and create a computed property for it there:
class DomainSchema: NSObject, NSCoding {
var domain: String
var schema: String
init(domain: String, schema: String) {
self.domain = domain
self.schema = schema
}
required init(coder decoder: NSCoder) {
self.domain = decoder.decodeObject(forKey: "domain") as? String ?? ""
self.schema = decoder.decodeObject(forKey: "schema") as? String ?? ""
}
func encode(with coder: NSCoder) {
coder.encode(domain, forKey: "domain")
coder.encode(schema, forKey: "schema")
}
}
extension UserDefaults {
var domainSchemas: [DomainSchema] {
get {
guard let data = UserDefaults.standard.data(forKey: "domainSchemas") else { return [] }
return (try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data)) as? [DomainSchema] ?? []
}
set {
UserDefaults.standard.set(try? NSKeyedArchiver.archivedData(withRootObject: newValue, requiringSecureCoding: false), forKey: "domainSchemas")
}
}
}
Usage:
UserDefaults.standard.domainSchemas = [.init(domain: "a", schema: "b"), .init(domain: "c", schema: "d")]
UserDefaults.standard.domainSchemas // [{NSObject, domain "a", schema "b"}, {NSObject, domain "c", schema "d"}]
If you prefer the Codable approach persisting the Data using UserDefaults as well:
struct DomainSchema: Codable {
var domain: String
var schema: String
init(domain: String, schema: String) {
self.domain = domain
self.schema = schema
}
}
extension UserDefaults {
var domainSchemas: [DomainSchema] {
get {
guard let data = UserDefaults.standard.data(forKey: "domainSchemas") else { return [] }
return (try? PropertyListDecoder().decode([DomainSchema].self, from: data)) ?? []
}
set {
UserDefaults.standard.set(try? PropertyListEncoder().encode(newValue), forKey: "domainSchemas")
}
}
}
Usage:
UserDefaults.standard.domainSchemas = [.init(domain: "a", schema: "b"), .init(domain: "c", schema: "d")]
UserDefaults.standard.domainSchemas // [{domain "a", schema "b"}, {domain "c", schema "d"}]
I think the best option would be to do not use UserDefaults, create a singleton "shared instance", declare a domainSchemas property there and save your json Data inside a subdirectory of you application support directory:
extension URL {
static var domainSchemas: URL {
let applicationSupport = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first!
let bundleID = Bundle.main.bundleIdentifier ?? "company name"
let subDirectory = applicationSupport.appendingPathComponent(bundleID, isDirectory: true)
try? FileManager.default.createDirectory(at: subDirectory, withIntermediateDirectories: true, attributes: nil)
return subDirectory.appendingPathComponent("domainSchemas.json")
}
}
class Shared {
static let instance = Shared()
private init() { }
var domainSchemas: [DomainSchema] {
get {
guard let data = try? Data(contentsOf: .domainSchemas) else { return [] }
return (try? JSONDecoder().decode([DomainSchema].self, from: data)) ?? []
}
set {
try? JSONEncoder().encode(newValue).write(to: .domainSchemas)
}
}
}
Usage:
Shared.instance.domainSchemas = [.init(domain: "a", schema: "b"), .init(domain: "c", schema: "d")]
Shared.instance.domainSchemas // [{domain "a", schema "b"}, {domain "c", schema "d"}]
You don't need to use NSKeyedArchiver to save custom objects into UserDefaults Because you have to change your struct into a class.
There is an easier solution and That's JSONDecoder and JSONEncoder.
Whenever you want to save a custom object into UserDefaults first convert it into Data by using JSONEncoder and when you want to retrieve an object from Userdefaults you do it by using JSONDecoder. Along with that I highly recommend you to write a separate class or struct to manage your data so that being said you can do:
struct DomainSchema: Codable {
var domain: String
var schema: String
}
struct PersistenceMangaer{
static let defaults = UserDefaults.standard
private init(){}
// save Data method
static func saveDomainSchema(domainSchema: [DomainSchema]){
do{
let encoder = JSONEncoder()
let domainsSchema = try encoder.encode(domainSchema)
defaults.setValue(followers, forKey: "yourKeyName")
}catch let err{
print(err)
}
}
//retrieve data method
static func getDomains() -> [DomainSchema]{
guard let domainSchemaData = defaults.object(forKey: "yourKeyName") as? Data else{return}
do{
let decoder = JSONDecoder()
let domainsSchema = try decoder.decode([DomainSchema].self, from: domainSchemaData)
return domainsSchema
}catch let err{
return([])
}
}
}
Usage:
let domains = PersistenceMangaer.standard.getDomains()
PersistenceMangaer.standard.saveDomainSchema(domainsTosave)
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
When encoding Int values you have to decode them with coder.decodeInteger(forKey: "xxx")
I have a JSON that has ID's in the root level:
{
"12345": {
"name": "Pim"
},
"54321": {
"name": "Dorien"
}
}
My goal is to use Codable to create an array of User objects that have both name and ID properties.
struct User: Codable {
let id: String
let name: String
}
I know how to use Codable with a single root level key and I know how to work with unknown keys. But what I'm trying to do here is a combination of both and I have no idea what to do next.
Here's what I got so far: (You can paste this in a Playground)
import UIKit
var json = """
{
"12345": {
"name": "Pim"
},
"54321": {
"name": "Dorien"
}
}
"""
let data = Data(json.utf8)
struct User: Codable {
let name: String
}
let decoder = JSONDecoder()
do {
let decoded = try decoder.decode([String: User].self, from: data)
decoded.forEach { print($0.key, $0.value) }
// 54321 User(name: "Dorien")
// 12345 User(name: "Pim")
} catch {
print("Failed to decode JSON")
}
This is what I'd like to do:
let decoder = JSONDecoder()
do {
let decoded = try decoder.decode([User].self, from: data)
decoded.forEach { print($0) }
// User(id: "54321", name: "Dorien")
// User(id: "12345", name: "Pim")
} catch {
print("Failed to decode JSON")
}
Any help is greatly appreciated.
You can use a custom coding key and setup User as below to parse unknown keys,
struct CustomCodingKey: CodingKey {
let intValue: Int?
let stringValue: String
init?(stringValue: String) {
self.intValue = Int(stringValue)
self.stringValue = stringValue
}
init?(intValue: Int) {
self.intValue = intValue
self.stringValue = "\(intValue)"
}
}
struct UserInfo: Codable {
let name: String
}
struct User: Codable {
var id: String = ""
var info: UserInfo?
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CustomCodingKey.self)
if let key = container.allKeys.first {
self.id = key.stringValue
self.info = try container.decode(UserInfo.self, forKey: key)
}
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CustomCodingKey.self)
if let key = CustomCodingKey(stringValue: self.id) {
try container.encode(self.info, forKey: key)
}
}
}
let decoder = JSONDecoder()
do {
let decoded = try decoder.decode(User.self, from: data)
print(decoded.id) // 12345
print(decoded.info!.name) // Pim
} catch {
print("Failed to decode JSON")
}
I have a simple object which conforms to the NSCoding protocol.
import Foundation
class JobCategory: NSObject, NSCoding {
var id: Int
var name: String
var URLString: String
init(id: Int, name: String, URLString: String) {
self.id = id
self.name = name
self.URLString = URLString
}
// MARK: - NSCoding
required init(coder aDecoder: NSCoder) {
id = aDecoder.decodeObject(forKey: "id") as? Int ?? aDecoder.decodeInteger(forKey: "id")
name = aDecoder.decodeObject(forKey: "name") as! String
URLString = aDecoder.decodeObject(forKey: "URLString") as! String
}
func encode(with aCoder: NSCoder) {
aCoder.encode(id, forKey: "id")
aCoder.encode(name, forKey: "name")
aCoder.encode(URLString, forKey: "URLString")
}
}
I'm trying to save an instance of it in UserDefaults but it keeps failing with the following error.
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attempt to insert non-property list object for key jobCategory'
This is the code where I'm saving in UserDefaults.
enum UserDefaultsKeys: String {
case jobCategory
}
class ViewController: UIViewController {
#IBAction func didTapSaveButton(_ sender: UIButton) {
let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com")
let userDefaults = UserDefaults.standard
userDefaults.set(category, forKey: UserDefaultsKeys.jobCategory.rawValue)
userDefaults.synchronize()
}
}
I replaced the enum value to key with a normal string but the same error still occurs. Any idea what's causing this?
You need to create Data instance from your JobCategory model using JSONEncoder and store that Data instance in UserDefaults and later decode using JSONDecoder.
struct JobCategory: Codable {
let id: Int
let name: String
}
// To store in UserDefaults
if let encoded = try? JSONEncoder().encode(category) {
UserDefaults.standard.set(encoded, forKey: UserDefaultsKeys.jobCategory.rawValue)
}
// Retrieve from UserDefaults
if let data = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as? Data,
let category = try? JSONDecoder().decode(JobCategory.self, from: data) {
print(category.name)
}
Old Answer
You need to create Data instance from your JobCategory instance using archivedData(withRootObject:) and store that Data instance in UserDefaults and later unarchive using unarchiveTopLevelObjectWithData(_:), So try like this.
For Storing data in UserDefaults
let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com")
let encodedData = NSKeyedArchiver.archivedData(withRootObject: category, requiringSecureCoding: false)
let userDefaults = UserDefaults.standard
userDefaults.set(encodedData, forKey: UserDefaultsKeys.jobCategory.rawValue)
For retrieving data from UserDefaults
let decoded = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as! Data
let decodedTeams = NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(decoded) as! JobCategory
print(decodedTeams.name)
Update Swift 4, Xcode 10
I have written a struct around it for easy access.
//set, get & remove User own profile in cache
struct UserProfileCache {
static let key = "userProfileCache"
static func save(_ value: Profile!) {
UserDefaults.standard.set(try? PropertyListEncoder().encode(value), forKey: key)
}
static func get() -> Profile! {
var userData: Profile!
if let data = UserDefaults.standard.value(forKey: key) as? Data {
userData = try? PropertyListDecoder().decode(Profile.self, from: data)
return userData!
} else {
return userData
}
}
static func remove() {
UserDefaults.standard.removeObject(forKey: key)
}
}
Profile is a Json encoded object.
struct Profile: Codable {
let id: Int!
let firstName: String
let dob: String!
}
Usage:
//save details in user defaults...
UserProfileCache.save(profileDetails)
Hope that helps!!!
Thanks
Swift save Codable object to UserDefault with #propertyWrapper
#propertyWrapper
struct UserDefault<T: Codable> {
let key: String
let defaultValue: T
init(_ key: String, defaultValue: T) {
self.key = key
self.defaultValue = defaultValue
}
var wrappedValue: T {
get {
if let data = UserDefaults.standard.object(forKey: key) as? Data,
let user = try? JSONDecoder().decode(T.self, from: data) {
return user
}
return defaultValue
}
set {
if let encoded = try? JSONEncoder().encode(newValue) {
UserDefaults.standard.set(encoded, forKey: key)
}
}
}
}
enum GlobalSettings {
#UserDefault("user", defaultValue: User(name:"",pass:"")) static var user: User
}
Example User model confirm Codable
struct User:Codable {
let name:String
let pass:String
}
How to use it
//Set value
GlobalSettings.user = User(name: "Ahmed", pass: "Ahmed")
//GetValue
print(GlobalSettings.user)
Save dictionary Into userdefault
let data = NSKeyedArchiver.archivedData(withRootObject: DictionaryData)
UserDefaults.standard.set(data, forKey: kUserData)
Retrieving the dictionary
let outData = UserDefaults.standard.data(forKey: kUserData)
let dict = NSKeyedUnarchiver.unarchiveObject(with: outData!) as! NSDictionary
Based on Harjot Singh answer. I've used like this:
struct AppData {
static var myObject: MyObject? {
get {
if UserDefaults.standard.object(forKey: "UserLocationKey") != nil {
if let data = UserDefaults.standard.value(forKey: "UserLocationKey") as? Data {
let myObject = try? PropertyListDecoder().decode(MyObject.self, from: data)
return myObject!
}
}
return nil
}
set {
UserDefaults.standard.set(try? PropertyListEncoder().encode(newValue), forKey: "UserLocationKey")
}
}
}
Here's a UserDefaults extension to set and get a Codable object, and keep it human-readable in the plist (User Defaults) if you open it as a plain text file:
extension Encodable {
var asDictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return try? JSONSerialization.jsonObject(with: data) as? [String : Any]
}
}
extension Decodable {
init?(dictionary: [String: Any]) {
guard let data = try? JSONSerialization.data(withJSONObject: dictionary) else { return nil }
guard let object = try? JSONDecoder().decode(Self.self, from: data) else { return nil }
self = object
}
}
extension UserDefaults {
func setEncodableAsDictionary<T: Encodable>(_ encodable: T, for key: String) {
self.set(encodable.asDictionary, forKey: key)
}
func getDecodableFromDictionary<T: Decodable>(for key: String) -> T? {
guard let dictionary = self.dictionary(forKey: key) else {
return nil
}
return T(dictionary: dictionary)
}
}
If you want to also support array (of codables) to and from plist array, add the following to the extension:
extension UserDefaults {
func setEncodablesAsArrayOfDictionaries<T: Encodable>(_ encodables: Array<T>, for key: String) {
let arrayOfDictionaries = encodables.map({ $0.asDictionary })
self.set(arrayOfDictionaries, forKey: key)
}
func getDecodablesFromArrayOfDictionaries<T: Decodable>(for key: String) -> [T]? {
guard let arrayOfDictionaries = self.array(forKey: key) as? [[String: Any]] else {
return nil
}
return arrayOfDictionaries.compactMap({ T(dictionary: $0) })
}
}
If you don't care about plist being human-readable, it can be simply saved as Data (will look like random string if opened as plain text):
extension UserDefaults {
func setEncodable<T: Encodable>(_ encodable: T, for key: String) throws {
let data = try PropertyListEncoder().encode(encodable)
self.set(data, forKey: key)
}
func getDecodable<T: Decodable>(for key: String) -> T? {
guard
self.object(forKey: key) != nil,
let data = self.value(forKey: key) as? Data
else {
return nil
}
let obj = try? PropertyListDecoder().decode(T.self, from: data)
return obj
}
}
(With this second approach, you don't need the Encodable and Decodable extensions from the top)
Well, investigated several similar topics here, done everything as suggested, but my computed property "previousUserData" returns me nil, when trying to cast the decoded object to my type. What's wrong?
#objc class PreviousUserData: NSObject, NSCoding {
var name: String
var phone: String
var email: String
func encode(with aCoder: NSCoder) {
aCoder.encode(name, forKey: "name")
aCoder.encode(phone, forKey: "phone")
aCoder.encode(email, forKey: "email")
}
required convenience init?(coder aDecoder: NSCoder) {
guard
let name = aDecoder.decodeObject(forKey: "name") as? String,
let phone = aDecoder.decodeObject(forKey: "phone") as? String,
let email = aDecoder.decodeObject(forKey: "email") as? String
else {
return nil
}
self.init(name: name, phone: phone, email: email)
}
init(name: String, phone: String, email: String) {
self.name = name
self.phone = phone
self.email = email
}
}
unarchived returns me nil, but data for key "userdata" is exists
var previousUserData: PreviousUserData? {
get {
if let object = UserDefaults.standard.object(forKey: "userdata") as? Data {
let unarchived = NSKeyedUnarchiver.unarchiveObject(with: object) as? PreviousUserData
return unarchived
}
return nil
}
set {
let encodedData: Data = NSKeyedArchiver.archivedData(withRootObject: previousUserData as Any)
UserDefaults.standard.setValue(encodedData, forKey: "userdata")
}
}
Actually you can't get valid data because the setter is wrong. You have to save newValue rather than previousUserData.
This is an slightly optimized version
var previousUserData: PreviousUserData? {
get {
guard let data = UserDefaults.standard.data(forKey: "userdata") else { return nil }
return NSKeyedUnarchiver.unarchiveObject(with: data) as? PreviousUserData
}
set {
guard let newValue = newValue else { return }
let encodedData = NSKeyedArchiver.archivedData(withRootObject: newValue)
UserDefaults.standard.set(encodedData, forKey: "userdata")
}
}
NSCoding is pretty heavy. In this case I'd recommend to use Codable to serialize the data as JSON or Property List. It gets rid of #objc, class and NSObject and reduces the entire code to
struct PreviousUserData : Codable {
var name: String
var phone: String
var email: String
}
var previousUserData: PreviousUserData? {
get {
guard let data = UserDefaults.standard.data(forKey: "userdata") else { return nil }
return try? JSONDecoder().decode(PreviousUserData.self, from: data)
}
set {
guard let newValue = newValue, let encodedData = try? JSONEncoder().encode(newValue) else { return }
UserDefaults.standard.set(encodedData, forKey: "userdata")
}
}