How use coredata in MVC - swift

Question

I can use Core Data in Functions but i can´t create in MVC, like this:
class addBD{
func add(){
let entityDescripition = NSEntityDescription.entityForName("Radar",inManagedObjectContext: managedObjectContext!)
let task = Radar(entity: entityDescripition!, insertIntoManagedObjectContext: managedObjectContext)
task.descricao = vlrDesc.text
task.latitude = fieldLatitude.text
task.longitude = fieldLongitude.text;
task.velocidade = picker.selectedRowInComponent(0)
managedObjectContext?.save(nil)
}
}
import UIKit
import CoreData
class adicionarRadar: UIViewController, NSFetchedResultsControllerDelegate {
func createTask() {
adic.add()
}
I have this errors:
Use of unresolved identifier 'managedObjectContext'
Use of unresolved identifier 'vlrDesc'
... all of the variables
class addBD{
func add(){
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext!
let entityDescripition = NSEntityDescription.entityForName("Radar",inManagedObjectContext: managedContext)
let task = Radar(entity: entityDescripition!, insertIntoManagedObjectContext: managedContext)
task.descricao = vlrDesc.text
task.latitude = fieldLatitude.text
task.longitude = fieldLongitude.text;
task.velocidade = picker.selectedRowInComponent(0)
managedContext.save(nil)
}
}
import UIKit
import CoreData
class adicionarRadar: UIViewController, NSFetchedResultsControllerDelegate {
var velocidade = ["40","50","70","90","100","120"]
var latitude:String = ""
var longitude:String = ""
var descrip:String = ""
var velocid:NSNumber = 0.0
var task: Radar? = nil
var idPicker:Int = 0
let adic = adiciona()
let managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
#IBOutlet weak var fieldLatitude: UITextField!
#IBOutlet weak var fieldLongitude: UITextField!
#IBOutlet weak var picker: UIPickerView!
#IBOutlet weak var vlrDesc: UITextField!
#IBAction func adicionar(sender: AnyObject) {
if task != nil {
editTask()
} else {
createTask()
}
dismissViewController()
}
func createTask() {
adic.add()
}
func editTask() {
task?.descricao = vlrDesc.text
task?.latitude = fieldLatitude.text
task?.longitude = fieldLongitude.text
task?.velocidade = picker.selectedRowInComponent(0)
println(picker.selectedRowInComponent(0))
managedObjectContext?.save(nil)
}
func dismissViewController() {
navigationController?.popViewControllerAnimated(true)
}
func textFieldSouldReturn (textField: UITextField) -> Bool{
textField.resignFirstResponder()
return true
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
self.view.endEditing(true)
}
override func viewDidLoad() {
vlrDesc.text = descrip
fieldLatitude.text = latitude
fieldLongitude.text=longitude
idPicker = Int(velocid)
picker.selectRow(idPicker, inComponent: 0, animated: true)
super.viewDidLoad()
// Do any additional setup after loading the view.
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
return velocidade[row]
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return velocidade.count
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

First, I would start by having a look here:
http://www.raywenderlich.com/85578/first-core-data-app-using-swift
That should get you started and should guide you on where you need to go.
For the first error: Use of unresolved identifier 'managedObjectContext', this is happening because you haven't actually retrieved this context from the AppDelegate
Use this in your add() function:
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext!
Now you have access to the managed context shared throughout your app for CoreData.
For the second error, you must have not declared or instantiated these variables somewhere in your code.
EDIT: Second Error:
So, the problem is that the function does not have a reference to those variables. They are declared in a different class and thus the class addBD can not interact with them.
One solution could be to add parameters to the function func add(), try changing it to something like
func add(vlrDesc: String, etc, etc)
And when you call add, pass in the vlrDesc and other variables as arguments.