I am trying to call one function in ViewController class which was written in view model class.But unfortunately that function is not getting called.I am not getting that where I did mistake.If anyone helps me ,Would be great. Thankyou!
//ViewController Class
import UIKit
class getDetailsViewController: UIViewController {
var getviewmodel: getDetaisViewModel?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBAction func getDetailsAction(_ sender: Any) {
getviewmodel?.getdetailscall()
}
}
//ViewModel Class
import Foundation
import Alamofire
import SwiftyJSON
class getDetaisViewModel{
var url: URL!
func getdetailscall(){
let headers:HTTPHeaders = ["Authorization":"application/json"]
print(headers)
url = URL(string: Constants.apiForGetDetails)
print(url)
let vc = getDetailsViewController.init(nibName: "getDetailsViewController", bundle: nil)
getWebService.requestService(url: url, method: .post, headers: headers, showLoaderFlag: true, viewController: vc, completion: { response in
guard response["code"].int != 503 else {
print("No internet connection")
return
}
guard response != .null else {
return
}
})
}
}
Becuase you haven't initialized the getviewmodel object
Change
var getviewmodel: getDetaisViewModel?
to
var getviewmodel = getDetaisViewModel()
Or initialize getviewmodel object in viewDidLoad method
override func viewDidLoad() {
super.viewDidLoad()
self.getviewmodel = getDetaisViewModel()
}
Change your class name to GetDetaisViewModel
Related
My Model saves data to Firestore. Once that data is saved, I'd like it to alert my ViewController so that a function can be called. However, nothing is being passed to my ViewController.
This is my Model:
protocol ProtocolModel {
func wasDataSavedSuccessfully(dataSavedSuccessfully:Bool)
}
class Model {
var delegate:ProtocolModel?
func createUserAddedRecipe(
docId:String,
completion: #escaping (Recipe?) -> Void) {
let db = Firestore.firestore()
do {
try db.collection("userFavourites").document(currentUserId).collection("userRecipes").document(docId).setData(from: recipe) { (error) in
print("Data Saved Successfully") // THIS OUTPUTS TO THE CONSOLE
// Notify delegate that data was saved to Firestore
self.delegate?.wasDataSavedSuccessfully(dataSavedSuccessfully: true)
}
}
catch {
print("Error \(error)")
}
}
}
The print("Data Saved Successfully") outputs to the console, but the delegate method right below it doesn't get called.
And this is my ViewController:
class ViewController: UIViewController {
private var model = Model()
override func viewDidLoad() {
super.viewDidLoad()
model.delegate = self
}
}
extension ViewController: ProtocolModel {
func wasDataSavedSuccessfully(dataSavedSuccessfully: Bool) {
if dataSavedSuccessfully == true {
print("Result is true.")
}
else {
print("Result is false.")
}
print("Protocol-Delegate Pattern Works")
}
}
Is there something I'm missing from this pattern? I haven't been able to notice anything different in the articles I've reviewed.
So I test your code and simulate something like that
import UIKit
protocol ProtocolModel {
func wasDataSavedSuccessfully(dataSavedSuccessfully:Bool)
}
class Model {
var delegate:ProtocolModel?
// I use this timer for simulate that firebase store data every 3 seconds for example
var timer: Timer?
func createUserAddedRecipe(
docId:String) {
timer = Timer.scheduledTimer(withTimeInterval: 3, repeats: true, block: { _ in
self.delegate?.wasDataSavedSuccessfully(dataSavedSuccessfully: true)
})
}
}
class NavigationController: UINavigationController {
var model = Model()
override func viewDidLoad() {
super.viewDidLoad()
model.delegate = self
// Call this method to register for network notification
model.createUserAddedRecipe(docId: "exampleId")
}
}
extension NavigationController: ProtocolModel {
func wasDataSavedSuccessfully(dataSavedSuccessfully: Bool) {
print(#function)
}
}
so you can see the result as image below, my delegate update controller that conform to that protocol.
well, im using 2 VCs, one with a textField where the user inputs the CityName, and another VC where it takes care of all the UI elements(like the temp, cityname, etc..), now I use also a NetWorkManager to take care of all the networking&JSON stuff.
the problem is im trying to transfer the data from the NetWorkManager to VC1 but for some reason the delegate aint working :( - basically the road should be like this : VC2 -> NetWorkManager -> VC1.
Here's my Code:
import Foundation
protocol NetworkManagerDelegate {
func didUpdateWeather(weather: WeatherModel)
}
struct NetworkManager {
let weatherURL = "https://api.openweathermap.org/data/2.5/weather?appid=2da9980c9a43e21c2cdb1f28316d151d&units=metric"
var delegate: NetworkManagerDelegate?
func fetchWeather(cityName: String) {
let urlString = "\(weatherURL)&q=\(cityName)"
performRequest(urlString: urlString)
}
func performRequest(urlString: String) {
if let url = URL(string: urlString) {
let session = URLSession(configuration: .default)
let task = session.dataTask(with: url) { (data, respone, error) in
if error != nil {
print(error!)
}
if let safeData = data {
if let weather = self.parseJSON(weatherData: safeData) {
print("Im not nil")
self.delegate?.didUpdateWeather(weather: weather)
}
}
}
task.resume()
}
}
func parseJSON(weatherData: Data) -> WeatherModel? {
let decoder = JSONDecoder()
do {
let decodedData = try decoder.decode(WeatherDataModel.self, from: weatherData)
let id = decodedData.weather[0].id
let cityName = decodedData.name
let temp = decodedData.main.temp
let weather = WeatherModel(conditionId: id, cityName: cityName ,temperatrue: temp)
print("Temp is: \(weather.temperatrueString)")
return weather
} catch {
print(error)
return nil
}
}
}
VC2:
import UIKit
import Foundation
class WeatherByCityController: UIViewController, UITextFieldDelegate {
// func didUpdateWeather(weather: WeatherModel) {
// print("Hi")
// }
//
#IBOutlet weak var cityTextField: UITextField!
#IBOutlet weak var updateWeatherBtn: UIButton!
var netWorkManager = NetworkManager()
override func viewDidLoad() {
super.viewDidLoad()
// netWorkManager.delegate = self
cityTextField.delegate = self
}
#IBAction func closeButtonTapped(_ sender: UIButton) {
dismiss(animated: true, completion: nil)
}
#IBAction func updateWeatherByCityTapped(_ sender: UIButton) {
//Calling delegate to update the City:
//Dismiss the VC:
dismiss(animated: true, completion: nil)
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
cityTextField.endEditing(true)
return true
}
func textFieldDidEndEditing(_ textField: UITextField) {
if let city = cityTextField.text {
netWorkManager.fetchWeather(cityName: city)
}
cityTextField.text = ""
}
}
VC1:
import UIKit
import Foundation
import CoreLocation
class WeatherScreen: UIViewController,NetworkManagerDelegate {
//Objects outlets:
#IBOutlet weak var conditionIcon: UIImageView!
#IBOutlet weak var tempLabel: UILabel!
#IBOutlet weak var cityLabel: UILabel!
//TableView Outlet:
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var segeControl: UISegmentedControl!
var models = [DailyWeatherEntry]()
var hourlyModels = [HourlyWeatherEntry]()
var netWorkManager = NetworkManager()
override func viewDidLoad() {
netWorkManager.delegate = self
tableView.register(HourlyTableViewCell.nib(), forCellReuseIdentifier: HourlyTableViewCell.identifier)
tableView.dataSource = self
}
override func viewWillAppear(_ animated: Bool) {
// Load things once the view will appear
}
#IBAction func locationBtnTapped(_ sender: UIButton) {
//Asking the user for a permission for using his location:
}
func didUpdateWeather(weather: WeatherModel) {
print("Hi")
}
}
extension WeatherScreen: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 2
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//creating the cell:
let cell = tableView.dequeueReusableCell(withIdentifier: "weatherCell", for: indexPath) as! HourlyTableViewCell
//Cell Configure:
cell.textLabel!.font = UIFont.systemFont(ofSize: 10)
return cell
}
}
Where is the code for the VC1 ? Without the code for VC 1 it is hard to give an answer. However i'll try to answer as this might be the scenario.
So basically what you are trying to do is make a network call from the VC2 and whatever the response it should be updated in VC1 which is already active somewhere else. Here you just have to set the delegate of the NetworkManger to the VC1 instance. So you have to get the instance of VC1 in VC2.
var netWorkManager = NetworkManager()
//Get this instance in your code
var vc1: UIViewController!
override func viewDidLoad() {
super.viewDidLoad()
// Here you will be setting the delegate
// to VC1 where you will be having the delegate methods
netWorkManager.delegate = vc1
cityTextField.delegate = self
}
While this method works I would not recommend using the network manager in such a way. Try to use completion handlers instead of delegates to get the data and then pass that values between the view controllers.
Edited:
Pass completion like this in the Network Manager performRequest function.
func performRequest(urlString: String, completion: #escaping (Bool, String?, Error?) -> Void) {
guard let url = URL(string: urlString) else {
completion(false, nil, NSError(domain: "URLString is not a valid URL", code: 100, userInfo: nil))
return
}
let session = URLSession(configuration: .default)
let task = session.dataTask(with: url) { (data, respone, error) in
guard let safeData = data, let weather = self.parseJSON(weatherData: safeData) else {
print("Empty data or JSON parse error")
completion(false, nil, error)
}
print("Im not nil")
completion(true, weather, nil)
}
task.resume()
}
And call the api request in the VC2.
#IBAction func updateWeatherByCityTapped(_ sender: UIButton) {
//Calling the api request. Pass your url string here
self. netWorkManager.performRequest(urlString: "") { (success, weather, error) in
guard success else {
print(error as Any)
return
}
// Here you have got the weather data.
// Don't know what is weather model. so simply passing the weather string.
self.delegate.didUpdateWeather(weather: weather)
//Dismiss the VC:
dismiss(animated: true, completion: nil)
}
}
Here adopt the NetworkManagerDelegate to VC1 and before presenting the VC2 set the delegate to VC1. Or if you are not presenting the VC2 from VC1 then use UserNotifications to send the weather data to the VC1.
This line of code var netWorkManager = NetworkManager() creates a new instance of network manager each time it is invoked.
In your case, the network manager in VC1 will not get called when the network manager you created in VC2 receives a network response. They are two separate entities.
There a few things you can think about:
If I understand your scenario correctly, your VC2 is used to get a city name from the user. Does VC2 really need to make a network call? You could restrict VC2 to only fetch the city name.
Make the networkManager a singleton. You can then call it from multiple places in your code. The networkManger can have method to 'fetch' and it can take in a completionHandler (as #Raja Vijaya kumar) had suggested.
I would like to understand what would be the best way to implement a delegate out UIViewController class
How can I manage the delegate using controller: UIViewController parameter of my function in AuthManager?
These are the two classes I'm working with .. I show you small examples to make you understand
class StartController: UIViewController {
#objc private func presentAuthFacebookController() {
AuthManager.signInWithFacebook(controller: self)
}
}
class AuthManager {
static func signInWithFacebook(controller: UIViewController) {
let loginManager = LoginManager()
loginManager.logIn(permissions: [.publicProfile, .email], viewController: controller) { (result) in
switch result {
case .cancelled : print("\n AuthFacebook: operazione annullata dall'utente \n")
case .failed(let error) : print("\n AuthFacebook: \(error) \n")
case .success(granted: _, declined: let declinedPermission, token: _):
let authVC = ExistingEmailController()
authVC.delegate = // ?????? (controller)
UIApplication.shared.windows.first?.rootViewController?.present(authVC, animated: true, completion: nil)
}
}
}
}
I personally don't think StartController should know about/conform to ExistingEmailControllerDelegate. But if you really want, you can declare controller as a composition type:
static func signInWithFacebook(controller: UIViewController & ExistingEmailControllerDelegate) {
...
authVC.delegate = controller
In my opinion, the whole point of having a AuthManager is to create a layer of abstraction on top of ExistingEmailController, and to encapsulate the logic of authentication. Therefore, StartController shouldn't know, or care, about ExistingEmailControllerDelegate. It only knows about AuthManager.
AuthManager should be the delegate of ExistingEmailController, which implies that signInWithFacebook should not be static, and AuthManager can have an AuthManagerDelegate that StartController conforms to:
class AuthManager : ExistingEmailControllerDelegate {
weak var delegate: AuthManagerDelegate?
func signInWithFacebook(controller: UIViewController) {
...
let authVC = ExistingEmailController()
authVC.delegate = self
UIApplication.shared.windows.first?.rootViewController?.present(authVC, animated: true, completion: nil)
}
func someMethodFromExistingEmailControllerDelegate() {
delegate?.someMethod() // delegating it self.delegate, which StartController conforms to
}
}
protocol AuthManagerDelegate : class {
func someMethod()
}
class StartController: UIViewController, AuthManagerDelegate {
var authManager: AuthManager!
override func viewDidLoad() {
authManager = AuthManager()
authManager.delegate = self
}
#objc private func presentAuthFacebookController() {
authManager.signInWithFacebook(controller: self)
}
func someMethod() {
// write here the code that you would have written in someMethodFromExistingEmailControllerDelegate
}
}
I had to update an app that i didn't touch for quite a while and now am facing an 'Fatal error: Unexpectedly found nil while unwrapping an Optional value' in DetailViewController::refreshWebView() when executing webView.loadRequest(myRequest) because webView is nil at this point in time.
I didn't change anything relating to how the DetailViewController is loaded and assigned to MasterViewController, so I am very confused as why this does not work anymore.
Was there something changed that i am not aware of? Or did I implement this whole thing incorrectly in the first place and it was coincidence that it worked?
import UIKit
protocol EventSelectionDelegate: class {
func eventSelected(_ newEvent: String)
}
class MasterViewController: UIViewController, UIWebViewDelegate {
var activityView: UIActivityIndicatorView!
weak var delegate: EventSelectionDelegate?
func detailChosen(_ detailUrlString: String) {
delegate?.eventSelected(detailUrlString)
activityView.startAnimating()
}
func transitionToDetail() {
if let detailViewController = self.delegate as? DetailViewController {
DispatchQueue.main.async {
self.activityView.stopAnimating()
self.splitViewController?.showDetailViewController(detailViewController, sender: nil)
}
}
}
}
// Helper function inserted by Swift 4.2 migrator.
fileprivate func convertToUIApplicationOpenExternalURLOptionsKeyDictionary(_ input: [String: Any]) -> [UIApplication.OpenExternalURLOptionsKey: Any] {
return Dictionary(uniqueKeysWithValues: input.map { key, value in (UIApplication.OpenExternalURLOptionsKey(rawValue: key), value)})
}
import UIKit
class DetailViewController: UIViewController, UIWebViewDelegate {
#IBOutlet weak var webView: UIWebView!
var animationWaitDelegate: MasterViewController!
var eventUrl: String! {
didSet {
self.refreshWebView()
}
}
override func viewDidLoad() {
super.viewDidLoad()
webView.delegate = self
}
func refreshWebView() {
let myURL = URL(string:eventUrl!)
let myRequest = URLRequest(url: myURL!)
webView.loadRequest(myRequest)
}
func webViewDidFinishLoad(_ webView: UIWebView) {
animationWaitDelegate.transitionToDetail()
}
}
extension DetailViewController: EventSelectionDelegate {
func eventSelected(_ newEvent: String) {
eventUrl = newEvent
}
}
// Helper function inserted by Swift 4.2 migrator.
fileprivate func convertToUIApplicationOpenExternalURLOptionsKeyDictionary(_ input: [String: Any]) -> [UIApplication.OpenExternalURLOptionsKey: Any] {
return Dictionary(uniqueKeysWithValues: input.map { key, value in (UIApplication.OpenExternalURLOptionsKey(rawValue: key), value)})
}
PS: I found a workaround in the meantime where I added a flag in DetailViewController that allows me to call refreshWebView in viewDidLoad if webView was nil the first time it was called.
First you have to update following code for null check, which will prevent crashing your app.
func refreshWebView() {
if webView != nil {
let myURL = URL(string:eventUrl!)
let myRequest = URLRequest(url: myURL!)
webView.loadRequest(myRequest)
}
}
After at transition add following code will fix your issue.
func transitionToDetail() {
if let detailViewController = self.delegate as? DetailViewController {
DispatchQueue.main.async {
self.activityView.stopAnimating()
detailViewController.loadViewIfNeeded() // Add this line of code
self.splitViewController?.showDetailViewController(detailViewController, sender: nil)
}
}
}
loadViewIfNeeded() method will load your controls before open screen if required.
I have a "Share on Facebook" button in my app at 3 different view controllers. So I wrote a class which name is "ShareCentral" and i want to do all sharing operations in this class. But for showing share dialog i need to pass uiviewcontroller to my ShareCentral class. I did like that:
class ShareCentral {
var UIVC: UIViewController
init(vc:UIViewController) {
self.UIVC = vc
}
func shareOnFacebook() {
var content = LinkShareContent(url: URL(string:userProfileLink)!)
do {
try ShareDialog.show(from: UIVC, content: content)
}catch (let error) {
print(error)
}
}
}
And this is my view controller:
class SettingsViewController: UIViewController {
let shareCentral = ShareCentral(vc: self)
#IBAction func shareButtonClicked(_ sender: AnyObject) {
self.shareCentral.shareOnFacebook()
}
}
I am getting following compiler error:
SettingsViewController.swift:40:41: Cannot convert value of type '(SettingsViewController) -> () -> (SettingsViewController)' to expected argument type 'UIViewController'
I know if i change the type of UIVC to "SettingsViewController" the problem will disappear. But as i said before i am gonna use this method in three different view controllers.
How can i resolve this problem?
Try this instead :
class ShareCentral {
unowned var UIVC: UIViewController
init(vc:UIViewController) {
self.UIVC = vc
}
func shareOnFacebook() {
var content = LinkShareContent(url: URL(string:userProfileLink)!)
do {
try ShareDialog.show(from: UIVC, content: content)
} catch (let error) {
print(error)
}
}
}
class SettingsViewController: UIViewController {
var shareVC: ShareVC!
override func viewDidLoad() {
super.viewDidLoad()
self.shareVC = ShareVC(vc: self)
}
#IBAction func shareButtonClicked(_ sender: AnyObject) {
self.shareCentral.shareOnFacebook()
}
}