Hi,
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 or observer of NSManagedObjectContextObjectsDidChangeNotification
or Incorrect guard value: or Main Thread Checker: UI API called
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)
}
}
}
[update db class](https://developer.apple.com/forums/content/attachment/31e8ff0d-abb3-4fb7-a346-c05f8a610b23){: .log-attachment}
in my appdelegate:
UpdateDbClass.updateDatabase(entityName: DbTable.VehiclesEntity.rawValue, completionHandler: {
print(" DB updated delegate")
})
update db class - https://developer.apple.com/forums/content/attachment/31e8ff0d-abb3-4fb7-a346-c05f8a610b23
keyvan1
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