use textFieldDidEndEditing textfield delegate to find 3 element in array - arrays

Question

My swift code below uses UITextFieldDelegate in textfield var enterT. nameString converts a core data entity to the array of strings, like [bob,bryan,jessica]. In textFieldDidEndEditing, I want the user to be able to enter any number, e.g 3 and third element from the array to be printed and then sort the array.
import UIKit
import CoreData
class ViewController: UIViewController,UITextFieldDelegate {
#IBOutlet var labelName : UILabel!
#IBOutlet var enterT : UITextField!
let appDelegate = UIApplication.shared.delegate as! AppDelegate //Singlton instance
var context:NSManagedObjectContext!
override func viewDidLoad() {
super.viewDidLoad()
openDatabse()
}
func textFieldDidEndEditing(_ textField: UITextField) {
guard let index = Int(textField.text!) else {
// display an alert about invalid text
return
}
joke(at: index)
}
func joke(at index : Int) {
let fetchRequest = NSFetchRequest<Users>(entityName: "Users")
fetchRequest.predicate = NSPredicate(format: "idx == %d", Int32(index))
do {
if let user = try context.fetch(fetchRequest).first {
print(user.username)
}
} catch {
print("Could not fetch \(error) ")
}
}
func openDatabse()
{
context = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "Users", in: context)
let newUser = NSManagedObject(entity: entity!, insertInto: context)
let newUser2 = NSManagedObject(entity: entity!, insertInto: context)
let newUser3 = NSManagedObject(entity: entity!, insertInto: context)
saveData(UserDBObj: newUser, UserDBObj2: newUser2, UserDBObj3: newUser3)
}
func saveData(UserDBObj:NSManagedObject,UserDBObj2:NSManagedObject,UserDBObj3:NSManagedObject)
{
UserDBObj.setValue("kim kardashian", forKey: "username")
UserDBObj2.setValue("jessica biel", forKey: "username")
UserDBObj3.setValue("Hailey Rienhart", forKey: "username")
print("Storing Data..")
do {
try context.save()
} catch {
print("Storing data Failed")
}
fetchData()
}
func fetchData()
{
print("Fetching Data..")
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
request.returnsObjectsAsFaults = false
do {
let result = try context.fetch(request)
for data in result as! [NSManagedObject] {
let userName = data.value(forKey: "username") as! String
print("User Name is : "+userName)
}
} catch {
print("Fetching data Failed")
}
}}

Answer 1

Convert the entered number to Int. If this succeeds pass the integer to joke and fetch the record matching the idx attribute.
Consider that indexes start with zero. If you want to enter numbers starting with one you have to decrement the index (joke(at: index - 1))
#IBOutlet var enterT : UITextField!
func textFieldDidEndEditing(_ textField: UITextField) {
guard let index = Int(textField.text!) else {
// display an alert about invalid text
return
}
joke(at: index)
}
func joke(at index : Int) {
let fetchRequest = NSFetchRequest<Users>(entityName: "Users")
fetchRequest.predicate = NSPredicate(format: "idx == %d", Int32(index))
do {
if let user = try context.fetch(fetchRequest).first {
print(user.username)
}
} catch {
print("Could not fetch \(error) ")
}
}
Note: I recommend to define idx and username as non-optional in the Core Data model. And make sure that all idx values are unique.