Swift - Core Data student info storage app errors - swift

Question

EDIT - i've played around with the code; still having issues.
i've been trying to modify the app in this tutorial so that i can enter student information and store it using core data. Ideally, i would like to be able to display that information on a label; but i haven't gotten that far yet. This is my first time working with core data and currently, i've hit a wall and need some assistance figuring out where in my code i've gone wrong and what to do to get it working.
So my questions are, how do i fix these errors.
and How would i got about displaying all the data after it's saved on a label.
Updated Screenshot
Updated Error Screenshot
Thanks in advance!
Code :
import UIKit
import CoreData
class ViewController: UIViewController {
#IBOutlet var name: UITextField!
#IBOutlet var address1: UITextField!
#IBOutlet var address2: UITextField!
#IBOutlet var city: UITextField!
#IBOutlet var state: UITextField!
#IBOutlet var zip: UITextField!
#IBOutlet var grade: UITextField!
#IBOutlet var status: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
func getContext () -> NSManagedObjectContext {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
return appDelegate.persistentContainer.viewContext
}
#IBAction func insertStudent(_ sender: AnyObject) {
let context = getContext()
let entityDescription = NSEntityDescription.entity(forEntityName: "Contacts", in: context)
let contact = NSManagedObject(entity: entityDescription!, insertInto: context) as! Contacts
contact.student_name = name.text
contact.address1 = address1.text
contact.address2 = address2.text
contact.city = city.text
contact.grade = grade.text
contact.state = state.text
contact.zip = zip.text
var error: NSError?
//save the object
do {
try context.save()
print("saved!")
} catch let error as NSError {
print("Could not save \(error), \(error.userInfo)")
} catch {
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

Looks like you are trying to mix Swift versions. See code examples below and see if this helps clear up the issue.
AppDelegate
import UIKit
import CoreData
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
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
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: "CDTest")
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)")
}
})
return container
}()
// MARK: - Core Data Saving support
func saveContext () {
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.save()
} catch {
// 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.
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
}
Functions to save and get data from CoreData in Swift 3.
func storeTranscription() {
let context = getContext()
//retrieve the entity that we just created
let entity = NSEntityDescription.entity(forEntityName: "ItemList", in: context)
let transc = NSManagedObject(entity: entity!, insertInto: context) as! ItemList
//set the entity values
transc.itemID = Double(itemid)
transc.productname = nametext
transc.amount = Double(amountDouble)
transc.stock = stockStatus
transc.inventoryDate = inventoryDate
//save the object
do {
try context.save()
print("saved!")
} catch let error as NSError {
print("Could not save \(error), \(error.userInfo)")
} catch {
}
}
func getTranscriptions () {
//create a fetch request, telling it about the entity
let fetchRequest: NSFetchRequest<ItemList> = ItemList.fetchRequest()
do {
//go get the results
let searchResults = try getContext().fetch(fetchRequest)
fetchedStatsArray = searchResults as [NSManagedObject]
//I like to check the size of the returned results!
print ("num of results = \(searchResults.count)")
//You need to convert to NSManagedObject to use 'for' loops
for trans in searchResults as [NSManagedObject] {
//get the Key Value pairs (although there may be a better way to do that...
print("\(trans.value(forKey: "productname")!)")
let mdate = trans.value(forKey: "inventoryDate") as! Date
print(mdate)
}
} catch {
print("Error with request: \(error)")
}
}
Your Code converted Swift 3
func getContext () -> NSManagedObjectContext {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
return appDelegate.persistentContainer.viewContext
}
#IBAction func insertStudent(_ sender: AnyObject) {
let context = getContext()
let entityDescription = NSEntityDescription.entity(forEntityName: "Contacts", in: context)
let contact = NSManagedObject(entity: entityDescription!, insertInto: context) as! Contacts
contact.student_name = name.text
contact.address1 = address1.text
contact.address2 = address2.text
contact.city = city.text
contact.grade = grade.text
contact.state = state.text
contact.zip = zip.text
var error: NSError?
//save the object
do {
try context.save()
print("saved!")
} catch let error as NSError {
print("Could not save \(error), \(error.userInfo)")
} catch {
}
}