Use and Make the core data compatible to iOS 8.0 to current Version

Kunal Prasad

26 October 2021

Core Data

Some time we need to use core data in application , for that we use in build core data provided by iOS but on the time of creation we select core data and default code attach to appdelegate class and its version is set to current , when we less the iOS version of application then the default code is not supported so we need such code that run from lower version to current version.

For this we need to add some code .

1: On creating a new project select core data.

2: add this code in appdelegate.swift class.

//
//  AppDelegate.swift
//  CoreDataText
//
//  Created by kunal prasad on 20/02/17.
//  Copyright © 2017 Webkul. All rights reserved.
//

import UIKit
import CoreData

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
 
  var context: NSManagedObjectContext?
    
    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        return true
    }

    func applicationWillResignActive(_ application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(_ application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
        // Saves changes in the application's managed object context before the application terminates.
        self.saveContext()
    }

    // MARK: - Core Data stack

    @available(iOS 10.0, *)
    lazy var persistentContainer: NSPersistentContainer = {

        let container = NSPersistentContainer(name: "CoreDataText")
        container.loadPersistentStores(completionHandler: { (storeDescription, error) in
            if let error = error as NSError? {
                fatalError("Unresolved error \(error), \(error.userInfo)")
            }
        })
        return container
    }()

    lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
        do {
            return try NSPersistentStoreCoordinator.coordinator(name: "CoreDataText")
        } catch {
            print("CoreData: Unresolved error \(error)")
        }
        return nil
    }()
    
    lazy var managedObjectContext: NSManagedObjectContext = {
        let coordinator = self.persistentStoreCoordinator
        var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
        managedObjectContext.persistentStoreCoordinator = coordinator
        return managedObjectContext
    }()
    
    
    // MARK: - Core Data Saving support

    func saveContext () {
        if #available(iOS 10.0, *) {
            context = persistentContainer.viewContext
        } else {
            context = managedObjectContext
        }
        if (context?.hasChanges)! {
            do {
                try context?.save()
            } catch {
                let nserror = error as NSError
                fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
            }
        }
    }

}

extension NSPersistentStoreCoordinator {
    
    /// NSPersistentStoreCoordinator error types
    public enum CoordinatorError: Error {
        /// .momd file not found
        case modelFileNotFound
        /// NSManagedObjectModel creation fail
        case modelCreationError
        /// Gettings document directory fail
        case storePathNotFound
    }
    
    /// Return NSPersistentStoreCoordinator object
    static func coordinator(name: String) throws -> NSPersistentStoreCoordinator? {
        
        guard let modelURL = Bundle.main.url(forResource: name, withExtension: "momd") else {
            throw CoordinatorError.modelFileNotFound
        }
        
        guard let model = NSManagedObjectModel(contentsOf: modelURL) else {
            throw CoordinatorError.modelCreationError
        }
        
        let coordinator = NSPersistentStoreCoordinator(managedObjectModel: model)
        
        guard let documents = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).last else {
            throw CoordinatorError.storePathNotFound
        }
        
        do {
            let url = documents.appendingPathComponent("\(name).sqlite")
            let options = [ NSMigratePersistentStoresAutomaticallyOption : true,
                            NSInferMappingModelAutomaticallyOption : true ]
            try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options)
        } catch {
            throw error
        }
        
        return coordinator
    }
}

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// AppDelegate.swift

// CoreDataText

// Created by kunal prasad on 20/02/17.

import UIKit

import CoreData

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

var context: NSManagedObjectContext?

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

// Override point for customization after application launch.

return true

}

func applicationWillResignActive(_ application: UIApplication) {

// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.

// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.

}

func applicationDidEnterBackground(_ application: UIApplication) {

// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.

// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.

}

func applicationWillEnterForeground(_ application: UIApplication) {

// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.

}

func applicationDidBecomeActive(_ application: UIApplication) {

// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.

}

func applicationWillTerminate(_ application: UIApplication) {

// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.

// Saves changes in the application's managed object context before the application terminates.

self.saveContext()

}

// MARK: - Core Data stack

@available(iOS 10.0, *)

lazy var persistentContainer: NSPersistentContainer = {

let container = NSPersistentContainer(name: "CoreDataText")

container.loadPersistentStores(completionHandler: { (storeDescription, error) in

if let error = error as NSError? {

fatalError("Unresolved error \(error), \(error.userInfo)")

}

})

return container

}()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {

do {

return try NSPersistentStoreCoordinator.coordinator(name: "CoreDataText")

} catch {

print("CoreData: Unresolved error \(error)")

}

return nil

}()

lazy var managedObjectContext: NSManagedObjectContext = {

let coordinator = self.persistentStoreCoordinator

var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)

managedObjectContext.persistentStoreCoordinator = coordinator

return managedObjectContext

}()

// MARK: - Core Data Saving support

func saveContext () {

if #available(iOS 10.0, *) {

context = persistentContainer.viewContext

} else {

context = managedObjectContext

}

if (context?.hasChanges)! {

do {

try context?.save()

} catch {

let nserror = error as NSError

fatalError("Unresolved error \(nserror), \(nserror.userInfo)")

}

extension NSPersistentStoreCoordinator {

/// NSPersistentStoreCoordinator error types

public enum CoordinatorError: Error {

/// .momd file not found

case modelFileNotFound

/// NSManagedObjectModel creation fail

case modelCreationError

/// Gettings document directory fail

case storePathNotFound

}

/// Return NSPersistentStoreCoordinator object

static func coordinator(name: String) throws -> NSPersistentStoreCoordinator? {

guard let modelURL = Bundle.main.url(forResource: name, withExtension: "momd") else {

throw CoordinatorError.modelFileNotFound

}

guard let model = NSManagedObjectModel(contentsOf: modelURL) else {

throw CoordinatorError.modelCreationError

}

let coordinator = NSPersistentStoreCoordinator(managedObjectModel: model)

guard let documents = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).last else {

throw CoordinatorError.storePathNotFound

}

do {

let url = documents.appendingPathComponent("\(name).sqlite")

let options = [ NSMigratePersistentStoresAutomaticallyOption : true,

NSInferMappingModelAutomaticallyOption : true ]

try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options)

} catch {

throw error

}

return coordinator

}

3: Now you can use the any function for insert or delete or update

exam:

Here is example for saving the data in core data “Person” is entity name and “name”,”age” is attribute.

    func saveName(name: String, data:String) {
        //1
        
        var managedContext: NSManagedObjectContext?
        
        let appDelegate =
            UIApplication.shared.delegate as! AppDelegate
        
        if #available(iOS 10.0, *) {
            managedContext = appDelegate.persistentContainer.viewContext
        } else {
            
            managedContext = appDelegate.managedObjectContext
        }
        
        //2
        let entity =  NSEntityDescription.entity(forEntityName: "Person",
                                                 in:managedContext!)
        
        let person = NSManagedObject(entity: entity!,
                                     insertInto: managedContext) as! Person
        
        //3
        
        person.name = name;
        person.age = data;
        
        //person.setValue(name, forKey: "name")
        //person.setValue("10", forKey: "age")
        //4
        do {
            try managedContext?.save()
            //5
            print("save data")
            
           // people.append(person)
        } catch let error as NSError  {
            print("Could not save \(error), \(error.userInfo)")
        }
    }

func saveName(name: String, data:String) {

//1

var managedContext: NSManagedObjectContext?

let appDelegate =

UIApplication.shared.delegate as! AppDelegate

if #available(iOS 10.0, *) {

managedContext = appDelegate.persistentContainer.viewContext

} else {

managedContext = appDelegate.managedObjectContext

}

//2

let entity = NSEntityDescription.entity(forEntityName: "Person",

in:managedContext!)

let person = NSManagedObject(entity: entity!,

insertInto: managedContext) as! Person

//3

person.name = name;

person.age = data;

//person.setValue(name, forKey: "name")

//person.setValue("10", forKey: "age")

//4

do {

try managedContext?.save()

//5

print("save data")

// people.append(person)

} catch let error as NSError {

print("Could not save \(error), \(error.userInfo)")

}

4: Select coredataxml file and click on editor and select create NSMangedsubclass.

5: then it will create a two file.

1: Person + CoreDataClass.swift

So write:

import Foundation
import CoreData
import UIKit


public class Person: NSManagedObject {
    static let entityName = "Person"
}

import Foundation

import CoreData

import UIKit

public class Person: NSManagedObject {

static let entityName = "Person"

}

2: Person + CoreDataProperties.swift

write this:

import Foundation
import CoreData


extension Person {

    @nonobjc public class func fetchRequest() -> NSFetchRequest<Person> {
        return NSFetchRequest<Person>(entityName: "Person");
    }

    @NSManaged public var age: String?
    @NSManaged public var name: String?
}

import Foundation

import CoreData

extension Person {

@nonobjc public class func fetchRequest() -> NSFetchRequest<Person> {

return NSFetchRequest<Person>(entityName: "Person");

}

@NSManaged public var age: String?

@NSManaged public var name: String?

}

6: for updation or view all .

create a Service.swift class

and write this:

//
//  Service.swift
//  CoreDataText
//
//  Created by kunal prasad on 20/02/17.
//  Copyright © 2017 Webkul. All rights reserved.
//

import Foundation

import CoreData

class Service{

    var context: NSManagedObjectContext
    
    init(context: NSManagedObjectContext){
        self.context = context
    }
    
    // Creates a new Person
    func create(name: String, age: String) -> Person {
        
        let newItem = NSEntityDescription.insertNewObject(forEntityName: Person.entityName, into: context) as! Person
        
        newItem.name = name
        newItem.age = age
        
        return newItem
    }
    
    // Gets a person by id
    func getById(id: NSManagedObjectID) -> Person? {
        return context.object(with: id) as? Person
    }
    
    // Gets all.
    func getAll() -> [Person]{
        return get(withPredicate: NSPredicate(value:true))
    }
    
    // Gets all that fulfill the specified predicate.
    // Predicates examples:
    // - NSPredicate(format: "name == %@", "Juan Carlos")
    // - NSPredicate(format: "name contains %@", "Juan")
    func get(withPredicate queryPredicate: NSPredicate) -> [Person]{
        let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: Person.entityName)
        
        fetchRequest.predicate = queryPredicate
        
        do {
            let response = try context.fetch(fetchRequest)
            return response as! [Person]
            
        } catch let error as NSError {
            // failure
            print(error)
            return [Person]()
        }
    }
    
    // Updates a person
    func update(updatedPerson: Person){
        if let person = getById(id: updatedPerson.objectID){
            person.name = updatedPerson.name
            person.age = updatedPerson.age
        }
    }
    
    // Deletes a person
    func delete(id: NSManagedObjectID){
        if let personToDelete = getById(id: id){
            context.delete(personToDelete)
        }
    }
    
    // Saves all changes
    func saveChanges(){
        do{
            try context.save()
        } catch let error as NSError {
            // failure
            print(error)
        }
    }


}

// Service.swift

// CoreDataText

// Created by kunal prasad on 20/02/17.

import Foundation

import CoreData

class Service{

var context: NSManagedObjectContext

init(context: NSManagedObjectContext){

self.context = context

}

// Creates a new Person

func create(name: String, age: String) -> Person {

let newItem = NSEntityDescription.insertNewObject(forEntityName: Person.entityName, into: context) as! Person

newItem.name = name

newItem.age = age

return newItem

}

// Gets a person by id

func getById(id: NSManagedObjectID) -> Person? {

return context.object(with: id) as? Person

}

// Gets all.

func getAll() -> [Person]{

return get(withPredicate: NSPredicate(value:true))

}

// Gets all that fulfill the specified predicate.

// Predicates examples:

// - NSPredicate(format: "name == %@", "Juan Carlos")

// - NSPredicate(format: "name contains %@", "Juan")

func get(withPredicate queryPredicate: NSPredicate) -> [Person]{

let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: Person.entityName)

fetchRequest.predicate = queryPredicate

do {

let response = try context.fetch(fetchRequest)

return response as! [Person]

} catch let error as NSError {

// failure

print(error)

return [Person]()

}

// Updates a person

func update(updatedPerson: Person){

if let person = getById(id: updatedPerson.objectID){

person.name = updatedPerson.name

person.age = updatedPerson.age

}

// Deletes a person

func delete(id: NSManagedObjectID){

if let personToDelete = getById(id: id){

context.delete(personToDelete)

}

// Saves all changes

func saveChanges(){

do{

try context.save()

} catch let error as NSError {

// failure

print(error)

}

6: for update write this function:

in your viewcontroller class

@IBAction func update_Database(_ sender: Any) {
    guard let appDelegate =
        UIApplication.shared.delegate as? AppDelegate else {
            return
    }
    var managedContext: NSManagedObjectContext!
    if #available(iOS 10.0, *) {
        managedContext =
            appDelegate.persistentContainer.viewContext
    } else {
        managedContext = appDelegate.managedObjectContext
    }
    let personService = Service(context: managedContext!)
    var AllData : [Person] = personService.get(withPredicate: NSPredicate(format: "name == %@", "radha"))
    
    // update the name after searching
    if AllData.count > 0{
           let update = personService.getById(id:AllData[0].objectID)
            update?.name = "radha kumari";
            personService.update(updatedPerson: update!)
            personService.saveChanges()
    }
}

@IBAction func update_Database(_ sender: Any) {

guard let appDelegate =

UIApplication.shared.delegate as? AppDelegate else {

return

}

var managedContext: NSManagedObjectContext!

if #available(iOS 10.0, *) {

managedContext =

appDelegate.persistentContainer.viewContext

} else {

managedContext = appDelegate.managedObjectContext

}

let personService = Service(context: managedContext!)

var AllData : [Person] = personService.get(withPredicate: NSPredicate(format: "name == %@", "radha"))

// update the name after searching

if AllData.count > 0{

let update = personService.getById(id:AllData[0].objectID)

update?.name = "radha kumari";

personService.update(updatedPerson: update!)

personService.saveChanges()

}

7: For viewall data

@IBAction func viewAll(_ sender: Any) {
    guard let appDelegate =
        UIApplication.shared.delegate as? AppDelegate else {
            return
    }
    var managedContext: NSManagedObjectContext!
    if #available(iOS 10.0, *) {
        managedContext =
            appDelegate.persistentContainer.viewContext
    } else {
        managedContext = appDelegate.managedObjectContext
    }
    
    //2
    let fetchRequest =
        NSFetchRequest<NSManagedObject>(entityName: "Person")
    do {
        people = try managedContext.fetch(fetchRequest)
        
        if people.count > 0{
            let person = people[0]
            print("ssss",person.value(forKeyPath: "name") as? String,people.count)
            print("ssss",person.value(forKeyPath: "age") as? String,people.count)
            
            
            
            
        }
        
    } catch let error as NSError {
        print("Could not fetch. \(error), \(error.userInfo)")
    }

    
    
}

@IBAction func viewAll(_ sender: Any) {

guard let appDelegate =

UIApplication.shared.delegate as? AppDelegate else {

return

}

var managedContext: NSManagedObjectContext!

if #available(iOS 10.0, *) {

managedContext =

appDelegate.persistentContainer.viewContext

} else {

managedContext = appDelegate.managedObjectContext

}

//2

let fetchRequest =

NSFetchRequest<NSManagedObject>(entityName: "Person")

do {

people = try managedContext.fetch(fetchRequest)

if people.count > 0{

let person = people[0]

print("ssss",person.value(forKeyPath: "name") as? String,people.count)

print("ssss",person.value(forKeyPath: "age") as? String,people.count)

}

} catch let error as NSError {

print("Could not fetch. \(error), \(error.userInfo)")

}