why core data is cleared when app is relaunch in swift?

Question

I am using core data as local DB to save local data in my iOS App. When the app is terminated and relaunched again then local data is cleared from core data. I am calling saveContext() from applicationDidEnterBackground and applicationWillTerminate methods. One thing is that I have changed the core data version. This change will do any effect on clear data after the relaunched app.

saveContext Method - :

func saveContext () -> Bool {
        let context = persistentContainer.viewContext
        var saveFlag = false
        if context.hasChanges {
            do {
                try context.save()
                saveFlag = true
            } catch {
                saveFlag = false
                let nserror = error as NSError
                fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
            }
        }
        return saveFlag
    }

Note : From above saveContext() method, Not goes inside context.hasChanges condition. So, not print an error message. It goes outside the condition and returns saveFlag as false.

Answer 1

var appDel:AppDelegate = UIApplication.shared.delegate as! AppDelegate

        let context = appDel.persistentContainer.viewContext
        var saveFlag = false
        if context.hasChanges {
            do {
                try context.save()
                saveFlag = true
            } catch {
                saveFlag = false
                let nserror = error as NSError
                fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
            }
        }
        return saveFlag
    }```

Please try the above code