Swift Core Data NSFetchRequest no results - swift

Question

I've encountered a problem when working with Core Data. I have this Core Data Model named 'Test.xcdatamodeld' and it contains only one entity named 'Data'. This Data entity contains one attribute named 'currCount' of type Int32.
What I'm trying to do is to read the value of 'currCount' but when I try to fetch something out of my entity 'Data' there are no results.
This is my fetching code:
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
var request = NSFetchRequest(entityName: "Data")
request.returnsObjectsAsFaults = false
var results: NSArray = context.executeFetchRequest(request, error: nil)!
var currCount:Int32 = 0
if results.count > 0 {
var res = results[0] as NSManagedObject
currCount = Int32(res.valueForKey("currCount") as Int)
println("Local Count: \(currCount)")
return currCount
}
else {
println("firstTime no Questions")
return 0
}
I always end up in the else-statement. I don't understand what I'm doing wrong. I've been going this way in another project and it works fine.
My AppDelegate.swift is as follows:
import UIKit
import CoreData
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {
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 throttle down OpenGL ES frame rates. 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 inactive 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:.
}
// 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 "com.jqsoftware.MyLog" in the application's documents Application Support directory.
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1] as NSURL
}()
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("Test", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
// 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("Test.sqlite")
var error: NSError? = nil
var failureReason = "There was an error creating or loading the application's saved data."
if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
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
error = 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
}()
// MARK: - Core Data Saving support
func saveContext () {
if let moc = self.managedObjectContext {
var error: NSError? = nil
if moc.hasChanges && !moc.save(&error) {
// 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.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
}
}
}
}
EDIT
Even if I save something to currCount before fetching it again, I get 0 results. This is the code I use for saving (which comes before the code above):
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
var request = NSFetchRequest(entityName: "Data")
request.returnsObjectsAsFaults = false
var results: NSArray = context.executeFetchRequest(request, error: nil)!
var currentCount:Int32 = 5
var newCount = NSEntityDescription.insertNewObjectForEntityForName("Data", inManagedObjectContext: context) as NSManagedObject
newHp.setValue(currentCount, forKey: "currCount")

Answer 1

Once you have inserted something on your context, you should save it to make changes permanent (I suppose you are using a SQLite store).
In other words, you need to run a context.save(&error) method.
Update 1
var error: NSError?
if !context.save(&error) {
println("Error saving context: \(error?.localizedDescription)\n\(error?.userInfo)")
}