Core Data freezes app - ios

I'm trying to add core data to iOS app. The problem is, when i try to get ManagedObjectContext it freezes.
Here's my stack:
// MARK: - Core Data stack
lazy var applicationDocumentsDirectory: NSURL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named "test" in the application's documents Application Support directory.
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1]
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = NSBundle.mainBundle().URLForResource("Model", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
do {
try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: - Core Data Saving support
func saveContext () {
if managedObjectContext.hasChanges {
do {
try managedObjectContext.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
}
}
it is in AppDelegate.
Here is code:
var appDel : AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate);
var context : NSManagedObjectContext = appDel.managedObjectContext
var newLine = NSEntityDescription.insertNewObjectForEntityForName("Track", inManagedObjectContext: context) as NSManagedObject
newLine.setValue("test123", forKey: "name")
newLine.setValue(String(points[points.count-2].x) + ";"+String(points[points.count-2].y), forKey: "start")
newLine.setValue(String(points[points.count-1].x) + ";"+String(points[points.count-1].y), forKey: "end")
do {try context.save()}
catch{}
it freezes on the second line. I copy pasted stack from another project, that probably can be the reason. After initializing, all fields of appDel are nil, but i guess it's ok because of lazy variables.

Related

saving data in core data over-writes all the records in swift

I have tableview which display list of animals.Tapping on each cell (or animal) it navigates to detail of animal and it has save button.
Whenever I save the information using core data, all the records in the core data gets over-write with last updated data.
I'm not sure what could be the reason. Reference for the code is taken form this post:
Swift 3 IOS 9 And IOS 10 Core Data
Below is the code
class CoreDataStack {
static var applicationDocumentsDirectory: URL = {
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return urls[urls.count-1]
}()
static var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = Bundle(for: CoreDataStack.self).url(forResource: "DatabaseTest", withExtension: "momd")! // type your database name here..
return NSManagedObjectModel(contentsOf: modelURL)!
}()
static var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: managedObjectModel)
let url = applicationDocumentsDirectory.appendingPathComponent("DatabaseTest.sqlite") // type your database name here...
var failureReason = "There was an error creating or loading the application's saved data."
let options = [NSMigratePersistentStoresAutomaticallyOption: NSNumber(value: true as Bool), NSInferMappingModelAutomaticallyOption: NSNumber(value: true as Bool)]
do {
try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject
dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
return coordinator
}()
static var managedObjectContext: NSManagedObjectContext = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = persistentStoreCoordinator
var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
static func getEntity<T: NSManagedObject>() -> T {
if #available(iOS 10, *) {
let obj = T(context: CoreDataStack.context)
return obj
} else {
guard let entityDescription = NSEntityDescription.entity(forEntityName: NSStringFromClass(T.self), in: CoreDataStack.context) else {
fatalError("Core Data entity name doesn't match.")
}
let obj = T(entity: entityDescription, insertInto: CoreDataStack.context)
return obj
}
}
// MARK: - Core Data Saving support
static func saveContext () {
if managedObjectContext.hasChanges {
do {
try managedObjectContext.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
}
}
}
On tapping save button, I call this code
let animalObj: animalTable = CoreDataStack.getEntity()
animalObj.Name = animalModel.Name
animalObj.Type = animalModel.Type
CoreDataStack.saveContext()
Not sure, where is the problem that it over-write all data in core data with last data saved.

Core Data is persistent after I remove it and restart my app

Good morning,
I'm working for the first time using CoreData with Swift 2.2. At the moment, I can add objects to my entity "Item" and I can remove all the items after I press a button "Remove everything". That's correct, but when I delete all the objects and then I restart my app, I still have the same Core Data before the "Remove everything" action.
That's how I delete the Core Data objects:
#IBAction func removeWishlist(sender: AnyObject) {
deleteAllData("ItemsWishlist")
getWishlist()
self.tableView.reloadData()
}
func deleteAllData(entity: String) {
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
let fetchRequest = NSFetchRequest(entityName: entity)
fetchRequest.returnsObjectsAsFaults = false
do
{
let results = try managedContext.executeFetchRequest(fetchRequest)
for managedObject in results
{
let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
managedContext.deleteObject(managedObjectData)
print("Deleted")
}
} catch let error as NSError {
print(error)
}
}
And it's working because when I press the button, the list is empty, but when I restart the app, it shows again the same items as before I pressed the "clear" button.
And that's my AppDelegate with the Core Data part:
// MARK: - Core Data stack
lazy var applicationDocumentsDirectory: NSURL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named "-.test" in the application's documents Application Support directory.
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1]
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = NSBundle.mainBundle().URLForResource("wishlist", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
do {
try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: - Core Data Saving support
func saveContext () {
if managedObjectContext.hasChanges {
do {
try managedObjectContext.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
}
}
What am I doing wrong with the Core Data? How can I resolve this issue?
Much appreciated,
Regards.
The reason why you got those objects back after restarting your app is because you did not save your NSManagedObjectContext after performing all the deletion so that those changes can be persisted to the persistence store you are using.
The context is like a virtual board. Think of your managed objects on a context as toys that you put on a table to play with. You can move them around, break them, move them out of the table, and bring new toys in. That table is your managed object context, and you can save its state when you are ready. When you save the state of the managed object context, this save operation will be communicated to the persistent store coordinator to which the context is connected. Then the persistent store coordinator will store the information to the persistent store and subsequently to disk.
func deleteAllData(entity: String) {
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
let fetchRequest = NSFetchRequest(entityName: entity)
fetchRequest.returnsObjectsAsFaults = false
do
{
let results = try managedContext.executeFetchRequest(fetchRequest)
for managedObject in results
{
let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
managedContext.deleteObject(managedObjectData)
print("Deleted")
}
} catch let error as NSError {
print(error)
}
appDelegate.saveContext()
}
For performance benefits, you should look into NSBatchDeleteRequest.

NSManagedObject Error

I have started learning core data in iOS now. I am currently getting fatal error: unexpectedly found nil while unwrapping an Optional value on the line of code below. I have been following lectures on youtube and few other places and had a look at their code too but failed to know the reason behind this error. If someone could provide me with an overview of it will be really helpful. Currently in my code I am just assigning values from entity, no fetching.
App Delegate:
lazy var applicationDocumentsDirectory: NSURL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named "com.alakh.singh.okejhbs" in the application's documents Application Support directory.
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1]
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = NSBundle.mainBundle().URLForResource("ActivityMonitor", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
do {
try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: - Core Data Saving support
func saveContext () {
if managedObjectContext.hasChanges {
do {
try managedObjectContext.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
}
}
}
ViewController:
#IBAction func cofirmLogin(sender: UIButton) {
let oct = ((UIApplication.sharedApplication().delegate as? AppDelegate)?.managedObjectContext)
var userNameValue = NSEntityDescription.insertNewObjectForEntityForName("LoginInformation", inManagedObjectContext: oct!) as! LoginInformation
userNameValue.loginUserName = loginUserName.text!
userNameValue.loginPin = Int(loginPin.text!)!
userNameValue = loginInfo
saveContext(oct!)
}
func saveContext (context : NSManagedObjectContext) {
if context.hasChanges {
do {
try context.save()
} catch {
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
}
Maybe something is not working as expected with the lazy variable. You could refactor your managed object context like this.
var managedObjectContext: NSManagedObjectContext {
get {
if _managedObjectContext == nil {
let coordinator = self.persistentStoreCoordinator
let moc = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
moc.persistentStoreCoordinator = coordinator
_managedObjectContext = moc
}
return _managedObjectContext!
}
}
var _rootContext: NSManagedObjectContext?
Also, make sure that the app delegate is returned as expected (perhaps break this up into several lines and check in the debugger).

Using Core Data in my Project [duplicate]

Facing issue "Value of type 'AppDelegate' has no member 'managedObjectContext' In new Xcode 8 (using Swift 3, iOS 10) when trying to create new context in View Controller
let context = (UIApplication.shared().delegate as! AppDelegate).managedObjectContext
In Xcode 8 there is no code for managedObjectContext inside AppDelegate.swift file. Core Data stack code inside AppDelegate.swift presented only with: lazy var persistentContainer: NSPersistentContainer property and func saveContext () . There is no managedObjectContext property.
How to create managedObjectContext using Swift 3 in Xcode 8) or maybe there is no need to do it using Swift 3 ?
In Swift3, you can access the managedObjectContext via the viewContext as
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
This option is available if Core data was enabled when creating the project. However, for existing project that you want to include core data, go through the normal process of adding the core data and add the following code which will allow you to get the
lazy var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "you_model_file_name")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
You will need to import the CoreData.
Note: For Swift3, the ManagedObject Subclass are generated automatically.
See more from WWDC 2016
Moved all the core data stack code to a single file and added iOS 10 and below iOS10. below is my try (not sure its fully up to the mark)
import Foundation
import CoreData
class CoreDataManager {
// MARK: - Core Data stack
static let sharedInstance = CoreDataManager()
private lazy var applicationDocumentsDirectory: URL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named in the application's documents Application Support directory.
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return urls[urls.count-1]
}()
private lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = Bundle.main.url(forResource: "CoreDataSwift", withExtension: "momd")!
return NSManagedObjectModel(contentsOf: modelURL)!
}()
private lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.appendingPathComponent("CoreDataSwift.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
do {
// Configure automatic migration.
let options = [ NSMigratePersistentStoresAutomaticallyOption : true, NSInferMappingModelAutomaticallyOption : true ]
try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject?
dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject?
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext = {
var managedObjectContext: NSManagedObjectContext?
if #available(iOS 10.0, *){
managedObjectContext = self.persistentContainer.viewContext
}
else{
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext?.persistentStoreCoordinator = coordinator
}
return managedObjectContext!
}()
// iOS-10
#available(iOS 10.0, *)
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/
let container = NSPersistentContainer(name: "CoreDataSwift")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
print("\(self.applicationDocumentsDirectory)")
return container
}()
// MARK: - Core Data Saving support
func saveContext () {
if managedObjectContext.hasChanges {
do {
try managedObjectContext.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
}
}
}
The solution by James Amo gets you most of the way there for iOS 10.0, but doesn't address iOS 9.0 and below, which can't access that method and needs to manually build the NSManagedObjectModel. Here is the solution that worked for me:
var context: NSManagedObjectContext?
if #available(iOS 10.0, *) {
context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
} else {
// iOS 9.0 and below - however you were previously handling it
guard let modelURL = Bundle.main.url(forResource: "Model", withExtension:"momd") else {
fatalError("Error loading model from bundle")
}
guard let mom = NSManagedObjectModel(contentsOf: modelURL) else {
fatalError("Error initializing mom from: \(modelURL)")
}
let psc = NSPersistentStoreCoordinator(managedObjectModel: mom)
context = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let docURL = urls[urls.endIndex-1]
let storeURL = docURL.appendingPathComponent("Model.sqlite")
do {
try psc.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: nil)
} catch {
fatalError("Error migrating store: \(error)")
}
}
It's clear that the change to 10.0 makes CoreData significantly simpler, but it's unfortunate that it's so painful for existing developers to make the jump...
To implement the above, just make sure to throw the persistentContainer into your AppDelegate.swift, defined in James Amo's answer.
NSPersistentContainer has a viewContext property that is an NSManagedObjectContext type.
As a side note, if you create a Master-Detail application in Xcode 8, Apple's sample code puts the managedObjectContext property in the MasterViewController.swift file and sets it by using said viewContext property in AppDelegate.
First, get AppDelegate object:-
let appDelegateObject = UIApplication.shared.delegate as! AppDelegate
And now, we can get managed object as:
let managedObject = appDelegateObject.persistentContainer.viewContext

iOS: Core Data light weight migration is throwing error

In my 1.0 version of the app, I have created a core data db named "MyApp.sqlite". When I do a core data light weight migration with the same name "MyApp.sqlite", i am getting the below error
Terminating app due to uncaught exception 'NSInternalInconsistencyException'
, reason: 'Can't modify an immutable model
Below is the code
// MARK: - Core Data stack
lazy var applicationDocumentsDirectory: NSURL = {
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1]
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = NSBundle.mainBundle().URLForResource("MyApp", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
print("hello")
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("MyApp.sqlite")
var err: NSError? = nil
var failureReason = "There was an error creating or loading the application's saved data."
let options = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true]
NSLog("url =---- \(url)")
do {
try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: options)
} catch let error as NSError {
print(error.localizedDescription)
coordinator = nil
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error
err = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext? = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
if coordinator == nil {
return nil
}
var managedObjectContext = NSManagedObjectContext()
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()

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