Swift 5
Bueno, la respuesta de Matt Price está perfectamente bien para pasar datos, pero voy a reescribirla en la última versión de Swift porque creo que los nuevos programadores encuentran que es bastante difícil debido a la nueva sintaxis y métodos / marcos, ya que la publicación original está en Objective-C.
Hay múltiples opciones para pasar datos entre los controladores de vista.
- Uso del controlador de navegación Push
- Usando Segue
- Usar delegado
- Usar el observador de notificaciones
- Usando bloque
Voy a reescribir su lógica en Swift con el último marco de iOS
Transferencia de datos a través del controlador de navegación Push : de ViewControllerA a ViewControllerB
Paso 1. Declarar variable en ViewControllerB
var isSomethingEnabled = false
Paso 2. Imprimir variable en el método ViewControllerB 'ViewDidLoad
override func viewDidLoad() {
super.viewDidLoad()
//Print value received through segue, navigation push
print("Value of 'isSomethingEnabled' from ViewControllerA : ", isSomethingEnabled)
}
Paso 3. En ViewController, pase los datos mientras empuja a través del controlador de navegación
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.isSomethingEnabled = true
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
Así que aquí está el código completo para:
ViewControllerA
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
//MARK:Passing Data through Navigation PushViewController
@IBAction func goToViewControllerB(_ sender: Any) {
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.isSomethingEnabled = true
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
}
}
ViewControllerB
import UIKit
class ViewControllerB: UIViewController {
//MARK: - Variable for Passing Data through Navigation push
var isSomethingEnabled = false
override func viewDidLoad() {
super.viewDidLoad()
//Print value received through navigation push
print("Value of 'isSomethingEnabled' from ViewControllerA : ", isSomethingEnabled)
}
}
Pasar datos a través de Segue : de ViewControllerA a ViewControllerB
Paso 1. Cree Segue de ViewControllerA a ViewControllerB y proporcione Identifier = showDetailSegue en Storyboard como se muestra a continuación
Paso 2. En ViewControllerB Declare un viable llamado isSomethingEnabled e imprima su valor.
Paso 3. En ViewController, un pase es el valor de SomeEnabled al pasar Segue
Así que aquí está el código completo para:
ViewControllerA
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
//MARK: - - Passing Data through Segue - -
@IBAction func goToViewControllerBUsingSegue(_ sender: Any) {
performSegue(withIdentifier: "showDetailSegue", sender: nil)
}
//Segue Delegate Method
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "showDetailSegue") {
let controller = segue.destination as? ViewControllerB
controller?.isSomethingEnabled = true//passing data
}
}
}
ViewControllerB
import UIKit
class ViewControllerB: UIViewController {
var isSomethingEnabled = false
override func viewDidLoad() {
super.viewDidLoad()
//Print value received through segue
print("Value of 'isSomethingEnabled' from ViewControllerA : ", isSomethingEnabled)
}
}
Pasar datos a través del delegado : de ViewControllerB a ViewControllerA
Paso 1. Declare el protocolo ViewControllerBDelegate en el archivo ViewControllerB pero fuera de la clase
protocol ViewControllerBDelegate: NSObjectProtocol {
// Classes that adopt this protocol MUST define
// this method -- and hopefully do something in
// that definition.
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?)
}
Paso 2. Declarar instancia de variable Delegate en ViewControllerB
var delegate: ViewControllerBDelegate?
Paso 3. Enviar datos para delegar dentro del método viewDidLoad de ViewControllerB
delegate?.addItemViewController(self, didFinishEnteringItem: "Data for ViewControllerA")
Paso 4. Confirme ViewControllerBDelegate en ViewControllerA
class ViewControllerA: UIViewController, ViewControllerBDelegate {
// to do
}
Paso 5. Confirme que implementará delegado en ViewControllerA
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.delegate = self//confirming delegate
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
Paso 6. Implemente el método delegado para recibir datos en ViewControllerA
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?) {
print("Value from ViewControllerB's Delegate", item!)
}
Así que aquí está el código completo para:
ViewControllerA
import UIKit
class ViewControllerA: UIViewController, ViewControllerBDelegate {
override func viewDidLoad() {
super.viewDidLoad()
}
//Delegate method
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?) {
print("Value from ViewControllerB's Delegate", item!)
}
@IBAction func goToViewControllerForDelegate(_ sender: Any) {
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.delegate = self
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
}
}
ViewControllerB
import UIKit
//Protocol decleare
protocol ViewControllerBDelegate: NSObjectProtocol {
// Classes that adopt this protocol MUST define
// this method -- and hopefully do something in
// that definition.
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?)
}
class ViewControllerB: UIViewController {
var delegate: ViewControllerBDelegate?
override func viewDidLoad() {
super.viewDidLoad()
//MARK: - - - - Set Data for Passing Data through Delegate - - - - - -
delegate?.addItemViewController(self, didFinishEnteringItem: "Data for ViewControllerA")
}
}
Paso de datos a través del observador de notificaciones : de ViewControllerB a ViewControllerA
Paso 1. Establecer y publicar datos en el Observador de notificaciones en ViewControllerB
let objToBeSent = "Test Message from Notification"
NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
Paso 2. Agregar el Observador de notificaciones en ViewControllerA
NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
Paso 3. Recibir el valor de los datos de notificación en ViewControllerA
@objc func methodOfReceivedNotification(notification: Notification) {
print("Value of notification : ", notification.object ?? "")
}
Así que aquí está el código completo para:
ViewControllerA
import UIKit
class ViewControllerA: UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
// add observer in controller(s) where you want to receive data
NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
}
//MARK: Method for receiving Data through Post Notification
@objc func methodOfReceivedNotification(notification: Notification) {
print("Value of notification : ", notification.object ?? "")
}
}
ViewControllerB
import UIKit
class ViewControllerB: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
//MARK:Set data for Passing Data through Post Notification
let objToBeSent = "Test Message from Notification"
NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
}
}
Paso de datos a través del bloque : de ViewControllerB a ViewControllerA
Paso 1. Declarar bloque en ViewControllerB
autorizacion varCompletionBlock: ((Bool) -> ())? = {_ en}
Paso 2. Establecer datos en bloque en ViewControllerB
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
Paso 3. Recibir datos de bloque en ViewControllerA
//Receiver Block
controller!.authorizationCompletionBlock = { isGranted in
print("Data received from Block is :", isGranted)
}
Así que aquí está el código completo para:
ViewControllerA
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
//MARK:Method for receiving Data through Block
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "showDetailSegue") {
let controller = segue.destination as? ViewControllerB
controller?.isSomethingEnabled = true
//Receiver Block
controller!.authorizationCompletionBlock = { isGranted in
print("Data received from Block is :", isGranted)
}
}
}
}
ViewControllerB
import UIKit
class ViewControllerB: UIViewController {
//MARK:Variable for Passing Data through Block
var authorizationCompletionBlock:((Bool)->())? = {_ in}
override func viewDidLoad() {
super.viewDidLoad()
//MARK:Set data for Passing Data through Block
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
}
}
Puede encontrar una aplicación de muestra completa en mi GitHub . Avíseme si tiene alguna pregunta al respecto.
@class ViewControllerB;definición superior a @protocol? Sin él, aparece el error "Tipo esperado" en ViewControllerB en la línea:- (void)addItemViewController:(ViewControllerB *)controller didFinishEnteringItem:(NSString *)item;dentro de la@protocoldeclaración