assigned delegate, but function is not called - ios

Question

Hi guys i would want to fire a method in SecondViewController from FirstViewController when the condition is meet. So i have used delegate to do so and my code is as follow:
FirstViewController:
import UIKit
import CoreBluetooth
import Foundation
class BluetoothViewController: UIViewController, ValueChangedDelegate {
if (characteristic.UUID == CBUUID(string: "2AF0")){
DataReceived.Single_Axis = Double(CharValue)
func peripheral(peripheral: CBPeripheral!, didUpdateValueForCharacteristic characteristic: CBCharacteristic!, error: NSError!) {
let singleaxisview = SingeAxisViewController()
singleaxisview.delegate = self
singleaxisview.valueChangedNotifyEveryone()
println("btfired")
}
SecondViewController
import UIKit
import CoreGraphics
protocol ValueChangedDelegate
{
func valueChanged(nValue : String)
}
class SingeAxisViewController: UIViewController {
var delegate : ValueChangedDelegate?
func valueChangedNotifyEveryone()
{
println("hello")
delegate?.valueChanged("changed value")
}
Can somebody point out to me what i missed?

Answer 1

Instead of BTController!.delegate = self you will have to use object of FirstViewController and set the delegate and you will also need to initialise the FirstViewController object. here is a sample code if you want to implement it. the first view controller implements the delegate methods and on call of btnClicked the second view controller is called and you get the response back to first view controller in the valueChanged method
import UIKit
class FirstViewController: UIViewController, ValueChangedDelegate {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
lbl.text = "inital value"
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
#IBOutlet weak var lbl: UILabel!
#IBAction func btnClicked(sender: AnyObject)
{
let secondViewController = SecondViewController()
secondViewController.delegate = self
secondViewController.valueChangedNotifyEveryone()
}
func valueChanged(nValue : String)
{
print(nValue)
lbl.text = nValue
}
}
Second view controller which implements the protocol and the also calls the protocol method from valueChangedNotifyEveryone method
import UIKit
protocol ValueChangedDelegate
{
func valueChanged(nValue : String)
}
class SecondViewController: UIViewController {
var delegate : ValueChangedDelegate?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func valueChangedNotifyEveryone()
{
delegate?.valueChanged("changed value")
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}