I try to format the code from NSCoding to Codable, the old one using NSKeyedUnarchiver to unarchive.
// ItemStore.swift
var allItems = [Item]()
let itemArchiveURL: URL = {
let documentsDirectories =
FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let documentDirectory = documentsDirectories.first!
return documentDirectory.appendingPathComponent("items.archive")
}()
init() {
if let archivedItems =
NSKeyedUnarchiver.unarchiveObject(withFile: itemArchiveURL.path) as? [Item] {
allItems = archivedItems
}
}
And now I adjust this function to the new one PropertyListDecoder().decode using Codable to unarchive.
init() {
do {
let itemsdata = try Data(contentsOf: itemArchiveURL)
if let archivedItems = try PropertyListDecoder().decode(allItems.self, from: itemsdata) as? [Item] {
allItems = archivedItems
}
}
catch {
print("Error archiving data: \(error)")
}
}
I'm confuse the Xcode report Cannot invoke 'decode' with an argument list of type '([Item], from: Data)' error message, why the Data(contentsOf:) not return the Data value?
Replace
if let archivedItems = try PropertyListDecoder().decode(allItems.self, from: itemsdata) as? [Item] {
With
allItems = try PropertyListDecoder().decode([Item].self, from: itemsdata)
Related
I don't understand why I am getting the error "EXC_BREAKPOINT (SIGTRAP)"
I have no compiler errors, and this is my first time I'm getting a trap error. I have a lot of googling but I don't grasp why this happens.
I have followed the debugger frame by frame going backwards it looks like this.
Backwards --> This is the row where my debugger stops
**///WHEN RUNNING THIS ERROR OCCURS**
private let _userSettings = UserSettings()
I access this from
static var shared: UserSettings {
return _userSettings
}
Which is called from
init() {
self.DisCourafeFamilyActivit = UserSettings.shared.loadData(pathToFile: LocalStoragePaths.DisCourafeFamilyActivit) ?? test
}
Which is in turn called from myModel
let userSettings = UserSettings.shared
TOP OF MY FILE I DO THIS
let _userSettings = UserSettings()
FULL UserSettings class
class UserSettings : ObservableObject {
let test = FamilyActivitySelection()
#Published var DisCourafeFamilyActivit : FamilyActivitySelection{
didSet {
UserSettings.shared.saveData(DisCourafeFamilyActivit, pathToFile: LocalStoragePaths.DisCourafeFamilyActivit)
}
}
init() {
self.DisCourafeFamilyActivit = UserSettings.shared.loadData(pathToFile: LocalStoragePaths.DisCourafeFamilyActivit) ?? test
}
static var shared: UserSettings {
return _userSettings
}
func saveData<T: Codable>(_ object: T, pathToFile: String) {
let documentsDirectory = FileManager().containerURL(forSecurityApplicationGroupIdentifier: "group.com.carlpalsson.superapp")
let archiveURL = documentsDirectory?.appendingPathComponent(pathToFile + ".json")
let encoder = JSONEncoder()
if let dataToSave = try? encoder.encode(object) {
do {
try dataToSave.write(to: archiveURL!)
} catch {
// TODO: ("Error: Can't save Counters")
return;
}
}
}
func loadData<T: Codable>(pathToFile: String) -> T? {
let documentsDirectory = FileManager().containerURL(forSecurityApplicationGroupIdentifier: "group.com.carlpalsson.superapp")
guard let archiveURL = documentsDirectory?.appendingPathComponent(pathToFile + ".json") else { return T.self as? T}
guard let codeData = try? Data(contentsOf: archiveURL) else {return T.self as? T}
let decoder = JSONDecoder()
if let decodedData = (try? decoder.decode(T.self, from: codeData)) {
return decodedData
}
return T.self as? T
}
}
How to access my Model from ViewController and use the Model data to load in table view????
Source Code Link
My ViewController looks like this
import UIKit
class ViewController: UIViewController {
var cclm: CountryCodeListModel?
override func viewDidLoad() {
super.viewDidLoad()
Timer.scheduledTimer(timeInterval: 3, target: self, selector: #selector(hello), userInfo: nil, repeats: true)
readLocalJSONFile(forName: "countryList")
// Do any additional setup after loading the view.
}
override func viewDidAppear(_ animated: Bool) {
}
#objc func hello()
{
print(cclm?.data?[0].flag)
}
}
and my model class look like this
struct CountryCodeList : Decodable {
var alpha2Code: String?
var alpha3Code: String?
var flag : String?
var name : String?
var code : String?
}
public struct CountryCodeListModel : Decodable {
var data : [CountryCodeList]?
}
var cclm: CountryCodeListModel?
//Method to load json
func readLocalJSONFile(forName name: String) {
do {
if let filePath = Bundle.main.path(forResource: name, ofType: "json") {
let fileUrl = URL(fileURLWithPath: filePath)
let data = try Data(contentsOf: fileUrl)
if let countryCodeObject = parse(jsonData: data) {
cclm = countryCodeObject
print(cclm?.data?[1].alpha2Code ?? "") //Printing Correct Value
}
}
} catch {
print("error: \(error)")
}
}
func parse(jsonData: Data) -> CountryCodeListModel?{
var dataArray : [Dictionary<String,Any>] = [[:]]
var country = Dictionary<String,Any>()
var modelData = Dictionary<String,Any>()
do {
// make sure this JSON is in the format we expect
if let json = try JSONSerialization.jsonObject(with: jsonData, options: []) as? Dictionary<String,Any> {
dataArray.removeAll()
for item in json["data"] as! [Dictionary<String, Any>] {
country = item
let url = URL(string: country["flag"] as? String ?? "")
let data = try? Data(contentsOf: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check / try-catch
let image = UIImage(data: data!)
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let fileName = url?.lastPathComponent // name of the image to be saved
let fileURL = documentsDirectory.appendingPathComponent(fileName ?? "")
if let data = image?.jpegData(compressionQuality: 1.0){
do {
try data.write(to: fileURL)
country["flag"] = fileURL.absoluteString
//print("file saved")
//urlAsString = fileURL.absoluteString
} catch {
print("error saving file:", error)
}
}
dataArray.append(country)
country.removeAll()
}
modelData["data"] = dataArray
//print(modelData)
let jsonData1 = try JSONSerialization.data(withJSONObject: modelData, options: [])
do {
let decodedData = try JSONDecoder().decode(CountryCodeListModel.self, from: jsonData1)
return decodedData
} catch {
print("error: \(error)")
}
}
} catch let error as NSError {
print("Failed to load: \(error.localizedDescription)")
}
return nil
}
Problem statement:
Iam reading local json and take the url value of flag key and download corresponding images to local. Once i download then am taking the localpath and update in the dictionary and then create JSON object and update my model class.
Now, am trying to access my model class from ViewController like below
print(CountryCodeListModel?.data?[0].name) //check screenshot for error
print(cclm?.data?[0].flag) // this prints nil always
Please check the error screenshots attached2
My JSON look like this
{
"meta":{
"success":true,
"message":"Successfully retrieved country details",
"code":"200"
},
"data":[
{
"alpha2Code":"AF",
"alpha3Code":"AFG",
"flag":"https://raw.githubusercontent.com/DevTides/countries/master/afg.png",
"name":"Afghanistan",
"code":"+93"
},
{
"alpha2Code":"AX",
"alpha3Code":"ALA",
"flag":"https://raw.githubusercontent.com/DevTides/countries/master/ala.png",
"name":"Aland Islands",
"code":"+358"
},
{
"alpha2Code":"AL",
"alpha3Code":"ALB",
"flag":"https://raw.githubusercontent.com/DevTides/countries/master/alb.png",
"name":"Albania",
"code":"+355"
},
{
"alpha2Code":"DZ",
"alpha3Code":"DZA",
"flag":"https://raw.githubusercontent.com/DevTides/countries/master/dza.png",
"name":"Algeria",
"code":"+213"
},
{
"alpha2Code":"AS",
"alpha3Code":"ASM",
"flag":"https://raw.githubusercontent.com/DevTides/countries/master/asm.png",
"name":"American Samoa",
"code":"+1684"
}
]
}
You are trying to decode something that doesn't exist.
print(CountryCodeListModel?.data?[0].name) //check screenshot for error
print(cclm?.data?[0].flag) // this prints nil always
The above code states that you want:
the name of
the variable data at position 0 of
the struct CountryCodeListModel.
What you want to do is:
the name of
the variable at position 0 of
an INSTANCE of the struct CountryCodeListModel.
For example...
func readLocalJSONFile(forName name: String) {
do {
if let filePath = Bundle.main.path(forResource: name, ofType: "json") {
let fileUrl = URL(fileURLWithPath: filePath)
let data = try Data(contentsOf: fileUrl)
if let countryCodeObject = parse(jsonData: data) {
cclm = countryCodeObject
print(cclm?.data?[1].alpha2Code ?? "") //Printing Correct Value
print(cclm?.data?[0].flag ?? "")
print(countryCodeObject?.data[0].flag ?? "") // Same as the line above
}
}
} catch {
print("error: \(error)")
}
}
Unless you are trying to use a static variable (at which you would use CountryCodeListModel.data), you need to make sure you are actually using an instance of the structure or an object of a class to reference your properties.
CAVEAT
CountryCodeListModel is a structure. CountryCodeListModel() is an instance of the structure CountryCodeListModel. Since you can have multiple instances of a structure, you need to reference a specific structure when accessing data. Thus, CountryCodeListModel.data will not work and it needs to be CountryCodeListModel().data. In this case, you have cclm.data.
I have the following coredata singleton class
in my appdelegate i try to update the data from json
but in my app when it launches i get different error messages regarding thread
like
Main Thread Checker: UI API called
or observer of NSManagedObjectContextObjectsDidChangeNotification
or Incorrect guard value
What is the problem and what changes should i make for it to work?
thanks
import CoreData
import Foundation
class CoreDataStack {
static let sharedManager = CoreDataStack()
private init() {} // Prevent clients from creating another instance.
//This is the name of your coreData Database
static let modelName = "myDB"
static let FirstLaunchKey = "firstLaunch"
lazy var managedObjectModel: NSManagedObjectModel = {
let modelURL = Bundle.main.url(forResource: CoreDataStack.modelName, withExtension: "momd")!
return NSManagedObjectModel(contentsOf: modelURL)!
}()
lazy var applicationDocumentsDirectory: URL = {
return NSPersistentContainer.defaultDirectoryURL()
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let persistentStoreURL = self.applicationDocumentsDirectory.appendingPathComponent(CoreDataStack.modelName + ".sqlite")
do {
// let dict = [NSSQLitePragmasOption: ["journal_mode":"DELETE"]]
try coordinator.addPersistentStore(ofType: NSSQLiteStoreType,
configurationName: nil,
at: persistentStoreURL,
options: [NSMigratePersistentStoresAutomaticallyOption: true,
NSInferMappingModelAutomaticallyOption: false])
} catch {
fatalError("Persistent store error! \(error)")
}
return coordinator
}()
fileprivate lazy var saveManagedObjectContext: NSManagedObjectContext = {
let moc = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
moc.persistentStoreCoordinator = self.persistentStoreCoordinator
return moc
}()
#objc lazy var mainObjectContext: NSManagedObjectContext = {
let managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext.parent = self.saveManagedObjectContext
return managedObjectContext
}()
func saveMainContext() {
guard mainObjectContext.hasChanges || saveManagedObjectContext.hasChanges else {
return
}
mainObjectContext.performAndWait() {
// print("save performAndWait")
do {
try self.mainObjectContext.save()
} catch {
fatalError("Error saving main managed object context! \(error)")
}
}
saveManagedObjectContext.perform() {
// print("save simple")
do {
try self.saveManagedObjectContext.save()
} catch {
fatalError("Error saving private managed object context! \(error)")
}
}
}
func removeDatabaseForVersion(version:String){
let previouslyVersion = UserDefaults.standard.bool(forKey: version)
if !previouslyVersion {
UserDefaults.standard.set(true, forKey: version)
// Default directory where the CoreDataStack will store its files
let directory = NSPersistentContainer.defaultDirectoryURL()
let url = directory.appendingPathComponent(CoreDataStack.modelName + ".sqlite")
let shmURL = directory.appendingPathComponent(CoreDataStack.modelName + ".sqlite-shm")
let walURL = directory.appendingPathComponent(CoreDataStack.modelName + ".sqlite-wal")
_ = try? FileManager.default.removeItem(at: url)
_ = try? FileManager.default.removeItem(at: shmURL)
_ = try? FileManager.default.removeItem(at: walURL)
}
}
}
in my appdelegate:
UpdateDbClass.updateDatabase(entityName: DbTable.VehiclesEntity.rawValue, completionHandler: {
print(" DB updated delegate")
})
in updatedb class:
import UIKit
import Alamofire
import CoreData
enum LoaderError:String{
case
JsonFailed,
PathFailed,
NoEntityDescription,
UnknownError
}
enum DbTable:String{
case
VehiclesEntity,
PhotosEntity,
ModelsEntity,
NewsEntity,
StylesEntity
}
class UpdateDbClass {
static func updateDatabase(entityName:String,completionHandler: #escaping () -> Void){
var url = URL(string: UrlRepository.VehiclesJsonUrl!)!
var table = ""
switch entityName {
case DbTable.VehiclesEntity.rawValue:
table = "Vehicles"
url = URL(string: UrlRepository.VehiclesJsonUrl!)!
case DbTable.PhotosEntity.rawValue:
table = "Photos"
url = URL(string: UrlRepository.PhotosJsonUrl!)!
table = "Styles"
url = Bundle.main.url(forResource: "Styles", withExtension: "json")!
// url = URL(string: UrlRepository.NewsJsonUrl!)!
default:
break
}
let uuid = UUID().uuidString
let parameters: Parameters = [
"id": uuid
]
let queue = DispatchQueue(label: "com.my.test", qos: .background, attributes: .concurrent)
AF.request(url, method: .get, parameters: parameters, encoding: URLEncoding(destination: .queryString), headers: nil).responseJSON(queue:queue){ response in
switch response.result {
case let .success(value):
if let items = value as? [[String: Any]] {
var itemsArray:[Int32] = []
for item in items{
if let id = item["id"] as? Int32{
itemsArray.append(id)
}
}
guard let entity = NSEntityDescription.entity(forEntityName: table, in:(CoreDataStack.sharedManager.mainObjectContext)) else {
fatalError("Could not find entity descriptions!")
}
switch entityName {
case DbTable.StylesEntity.rawValue: //Styles
checkDeletedRecords(jsonItems: itemsArray,table: table)
for item in items{
guard let id = item["id"] as? Int32 else {return}
//Check if not exists
if !CheckIfExists(id: id,table:table){
print("id \(id) does not exist")
//Insert Record
let object = Styles(entity: entity, insertInto: CoreDataStack.sharedManager.mainObjectContext)
object.setValue(item["id"], forKey: "id")
object.setValue(item["style"] as! String, forKey: "style")
object.setValue(item["image"] as! String, forKey: "image")
CoreDataStack.sharedManager.saveMainContext()
}
else{ //Update Record
// print("id \(item["id"]) exists")
do{
let fetchRequest = NSFetchRequest<Styles>(entityName:"Styles")
let predicate = NSPredicate(format: "id == %d",item["id"] as! Int32)
fetchRequest.predicate = predicate
let req = try CoreDataStack.sharedManager.mainObjectContext.fetch(fetchRequest)
let object = req[0] as NSManagedObject
object.setValue(item["style"] as! String, forKey: "style")
object.setValue(item["image"] as! String, forKey: "image")
CoreDataStack.sharedManager.saveMainContext()
}catch{
print("there was an error")
}
completionHandler()
}
}
break;
default:
break
}
}
break
case let .failure(error):
print(error as NSError)
break
}
}
}
}
protocol CoreDataWorkerProtocol {
associatedtype EntityType
}
enum VoidResult {
case success
case failure(NSError)
}
Response json is called on background thread and you are trying to use viewContext in background thread.
You should use perform block if you want to use viewContext in background.
For example like this
AF.request(:).responseJSON(queue:queue){ response in
let mainContext = CoreDataStack.sharedManager.mainObjectContext
mainContext.perform {
guard let entity = NSEntityDescription.entity(forEntityName: table, in: mainContext) else {
fatalError("Could not find entity descriptions!")
}
}
}
I cannot figure out how to save data (multiple properties) in Documents Directory with SwiftUI. I know two variants, 1st - when you have one array property and that works great, the problem here - I don't know how to add additional properties to it. Or maybe it is normal to create about 3 swift-files like this for each property for one project.
1 variant, saving in Documents Directory:
class Stack: ObservableObject {
#Published var cards: [Card]
static let saveKey = "SavedCards"
init() {
self.cards = []
if let data = loadFile() {
if let decoded = try? JSONDecoder().decode([Card].self, from: data) {
self.cards = decoded
return
}
}
}
func add(card: Card) {
cards.insert(card, at: 0)
save()
}
func save() {
if let encoded = try? JSONEncoder().encode(cards) {
saveFile(data: encoded)
}
}
private func saveFile(data: Data) {
let url = getDocumentsDirectory().appendingPathComponent(Self.saveKey)
do {
try data.write(to: url, options: [.atomicWrite, .completeFileProtection])
} catch let error {
print("Could not write data: " + error.localizedDescription)
}
}
func loadFile() -> Data? {
let url = getDocumentsDirectory().appendingPathComponent(Self.saveKey)
if let data = try? Data(contentsOf: url) {
return data
}
return nil
}
private func getDocumentsDirectory() -> URL {
let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return paths[0]
}
}
The 2nd variant is to use CodingKeys for each property. But I cannot figure out how exactly I can add methods here and use it in other views, to save data from pressing a button for example. It seems like I have to encode and decode in every view over and over again for each change of data. It just seems wrong.
2 variant with Coding Keys
class Profile: Codable, ObservableObject {
enum CodingKeys: CodingKey {
case categories, playedCards, playedRounds
}
#Published var categories: [Category] = [Category.red, .green, .blue, .yellow, .pink, .gray]
#Published var playedCards = 0
#Published var playedRounds = 0
init() { }
required init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
categories = try container.decode([Category].self, forKey: .categories)
playedCards = try container.decode(Int.self, forKey: .playedCards)
playedRounds = try container.decode(Int.self, forKey: .playedRounds)
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(categories, forKey: .categories)
try container.encode(playedCards, forKey: .playedCards)
try container.encode(playedRounds, forKey: .playedRounds)
}
}
So my question is how to use 1 variant with multiple variables. Or if I should use the 2nd variant, how can I "nicely" encode and decode variables from other views.
For now, my solution for 2nd variant is to write standard decode() / encode() methods in ContentView and use it in onDismiss: of Sheet Views to save data from different screens without repetitions.
func loadData() {
let filename = getDocumentsDiretory().appendingPathComponent("SavedData")
do {
let data = try Data(contentsOf: filename)
profile = try JSONDecoder().decode(Profile.self, from: data)
} catch {
print("Unable to load saved profile data")
}
}
func saveData() {
do {
let filename = getDocumentsDiretory().appendingPathComponent("SavedData")
let data = try JSONEncoder().encode(self.profile)
try data.write(to: filename, options: [.atomic, .completeFileProtection])
} catch {
print("Unable to save profile data")
}
}
func getDocumentsDiretory() -> URL {
let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return paths[0]
}
.sheet(isPresented: $showingSheet, onDismiss: saveData) {
ProfileView()
}
.onAppear(perform: loadData)
I encode a array of structs. When encoded the returned data has some bytes, which tells me that something was written to the file. But when I decode it returns nil. I don't get any error while decoding. I dont understand why it returns nil after decode.
var allEndpts = [EndPt]()
struct EndPt : Codable {
var contactStruct = ContactStruct()
var purpose: String = String()
}
struct ContactStruct: Codable {
var firstName:String? = nil
var lastName:String? = nil
}
private func saveEndPoints() {
do {
delegate.documentDirectoryUrl = try FileManager.default.url(
for: .documentDirectory,
in: .userDomainMask,
appropriateFor: nil,
create: false
)
let localFileUrl:URL =
delegate.documentDirectoryUrl!
.appendingPathComponent("EndPoints")
UserDefaults.standard.set(localFileUrl, forKey: "localEndPtUrl")
print("localEndPtUrl: \(localFileUrl)")
do {
let encoder = PropertyListEncoder()
let data = try encoder.encode(self.allEndpts)
try data.write(to: localFileUrl)
} catch {
print(error)
}
} catch {
print("error")
}
retrieveFromFile()
}
func retrieveFromFile() {
typealias TempArray = [EndPt]
var temp: TempArray?
let localFileUrl = UserDefaults.standard.url( forKey: "localEndPtUrl")
print("localEndPtUrl: \(localFileUrl)")
do {
let data = try Data(contentsOf: localFileUrl!)
let temp = try PropertyListDecoder().decode(TempArray.self, from: data)
print("EndPt Array Dump: ", temp)
} catch {
print("read error:", error)
}
}
The problem is that
var temp: TempArray?
will always be nil unless you change it. And you never change it. When you say
let temp = try PropertyListDecoder().decode(TempArray.self, from: data)
that is a different temp.