I have a viewController with a tableView, and another viewController that contains data that I'm trying to pass to the tableView. To add entries to the tableView I used segues, but the problem with segues is that they don't update the tableView permanently. They merely create an instance of the ViewController and add the entry there, but the original object remains unchanged. Both ViewControllers are part of a tab bar controller. What I want is to update the table permanently. Meaning, I want to be able to navigate to the viewController where the table is defined and see that's an entry has been added. Here's the code for the viewController with the tableView:
import UIKit
class FavoritesViewController: UIViewController {
public var shops = [
"hello world",
"hello world",
"hello world"
]
#IBOutlet weak var table: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
table.delegate = self
table.dataSource = self
table.reloadData()
}
}
extension FavoritesViewController: UITableViewDelegate, UITableViewDataSource{
func add(_ shopName: String) {
print(shopName)
shops.append(shopName)
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return shops.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell",for: indexPath)
cell.textLabel?.text = shops[indexPath.row]
return cell
}
// define the action. In this case "delete"
func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
return .delete
}
// do the actual deleting
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
tableView.beginUpdates()
shops.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
tableView.endUpdates()
}
}
}
And here's how I'm trying to update (in the case adding an entry) the tableView in the other viewController:
class MainViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate{
public var shopName:String?
// there are also many other vars, but they're irrelevant
public var favoritesDestinationVC = FavoritesViewController()
// prepares the data for the segue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToFavs" {
favoritesDestinationVC = segue.destination as! FavoritesViewController
if let newShopName = shopName {
favoritesDestinationVC.shops.append(newShopName)
}
}
}
}
However, when I add the entry the to the table, the segue creates an instance of FavoritesViewController, adds that entry there, and then displays it in a popup window like this:
But when I dismiss this window the changes disappear (the tableView remains the same; 3 times "Hello World").
I want the changes to be saved in the tableView after dismissing this window. Any idea on how to do that? On how to make those changes permanent?
By your explanation, it looks like. Segue is defined as presenting FavoritesViewController modally. and this behavior is expected. By your implementation. Since you are not updating the view controller object which is part of the tab bar controller.
To make the changes in the controller in tab bar controller, Either you access that object using tabcontroller.viewcontrollers. Communicate using another way like a delegate or notification.
Edit:
It totally depends on where you want to access FavoritesViewController.
If you want to access from TabBarViewController (based on your view hierarchy it may change. be careful about index and typecasting):
let favVC = self.viewControllers?[1] as! FavoritesViewController
favVC.shops.append(newShopName)
If you want to access from a view controller which is part of same tab bar controller:
var favVC = self.tabBarController?.viewControllers?[1] as! FavoritesViewController
favVC.shops.append(newShopName)
Note: Viewcontrollers's index depends on viewcontroller order in your tab bar controller. And type casting depends upon your view hierarchy.
I need the tableView to perform reloadData() after a row has been added via a textView. My tableViews all use the reusable code which works fine.
Below is my Reusable TableViewCode.
class ReusableSubtitleTable: NSObject, UITableViewDataSource, UITableViewDelegate{
let cell = "cell"
var dataArray = [String]()
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) {
print("DataArray count from table view = \(dataArray.count)")
return dataArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let selfSizingCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! SelfSizingCell
let num = indexPath.row
selfSizingCell.titleText.text = (stepText[num])
selfSizingCell.subtitleText.text = dataArray[num]
return selfSizingCell
}
}
The function below uses the reusable code to display the table which works fine.
class DetailViewController: UIViewController {
let step = 13
var tableView: UITableView!
let dataSource = ReusableSubtitleTable()
var selectedEntry: JournalEntry!
var dataModel = [String]()
var didSave = false
var coreDataManager = CoreDataManager()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = dataSource
tableView.dataSource = dataSource
dataSource.dataArray = dataModel
#IBAction func unwindToDetail( _ sender: UIStoryboardSegue) {
dataModel[10] = step11
didSave = coreDataManager.updateEntry(step11: step11, selectedEntry: selectedEntry)
}
}
The problem come in when a user wants to add to the last row. The user taps a button and is taken to the next controller which is a TextView. When user finishes their entry they tap the 'Save' button which returned to the DetailViewController via an unwind. The selectedEntry is saved and the dataModel updated. Now the table view needs to reload to display this added text.
I've tried adding tableView.ReloadData() after didSave. I've tried a Dispatch and tried saving the data before returning from the textView via the unwind but that doesn't work either.
I tried adding the below function to ReusableTableView and called it after the coredata update - there are no errors but it does not reload the table.
func doReload(){
tableView.reloadData()
}
I have verified that the data is saved and it does displays if I return to the summary controller and then go forward the DetailViewController.
Any help is appreciated.
Placing the UITableView reloadData() within either viewWillAppear or viewDidAppear should resolve this issue.
For example:
func viewDidAppear(_ animated: bool) {
super.viewDidAppear(animated)
tableView.reloadData()
}
This is because the view hierarchy isn't yet regarded as "visible" during the segue unwind and why you see it work by going back to reloading the view controller. The reloadData() function, for efficiency, only redisplays visible cells and at the time of the unwind the cells aren't "visible".
Apple Documentation - UITableView.reloadData():
For efficiency, the table view redisplays only those rows that are
visible.
I have viewcontroller and it has split by two views. one is view which cotrolled by tableviewcontroller which is childcontroller of viewcontroller, and one is statusview which is show data directly when tableviewcontrollersdidselectrowatindexpathis called. but when i cant reload my data in statusview when i called didselectrowatindexpath. i can relaod my data in tableview but status view does not reflect data.
the darkgray area is statusview and middle view is tableview.
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
self.tableView.reloadData()
}
by this code i can reload my data in tableview . but when i use setneedsDisplay or setneedslayout of parentController(viewcontroller) it crash. how can i solve this problem?
In this case you will need one of these two options:
Create a protocol that your main UIViewController will implement, so that UITableViewController can pass data via the delegate to its parent view controller
Post a UINotification in the UITableViewController and receive this notification in your status bar view and display the data.
Lets explore both options:
Define a protocol, in this example I am only sending a String of the cell that was tapped on:
#objc protocol YourDataProtocol {
func didSelectCell(withString string: String)
}
Next add a delegate property to your UITableViewController
class YourTableViewController: UIViewController {
weak var delegate: YourDataProtocol?
...
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = tableView.cellForRow(at: indexPath)
//call the delegate method with your text - in this case just text from textLabel
if let text = cell?.textLabel?.text {
delegate?.didSelectCell(withString: text)
}
}
}
Make your UIViewContoller be the delegate of the UITableViewController subclass:
class YourViewController: UIViewController, YourDataProtocol {
...
let yourTableVC = YourTableViewController(...
yourTableVC.delegate = self
func didSelectCell(withString string: String) {
statusBar.text = string//update the status bar
}
}
Second option is with using NotificationCenter
In your UITableViewController you post a notification
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = tableView.cellForRow(at: indexPath)
if let text = cell?.textLabel?.text {
let notificatioName = Notification.Name("DataFromTableViewCell")
NotificationCenter.default.post(name: notificatioName, object: nil, userInfo: ["YourData": text])
}
}
In status bar you start listening to this notification
NotificationCenter.default.addObserver(self, selector: #selector(didReceiveData(_:)), name: notificatioName, object: nil)
#objc func didReceiveData(_ notification: Notification) {
if let userData = notification.userInfo, let stringFromCell = userData["YourData"] {
print(stringFromCell)
}
}
I've already looked at the post UITableView.reloadData() is not working. I'm not sure that it applies to my situation, but let me know if I'm wrong.
My app has a tableView. From the main viewController I am opening another viewController, creating a new object, and then passing that object back to the original viewController, where it is added to an array called timers. All of that is working fine. However, when I call tableView.reloadData() in didUnwindFromNewTimerVC() to display the updated contents of the timers array, nothing happens.
NOTE: I have verified that the timers array is updated with the new object. Its count increments, and I can access its members. Everything else in didUnwindFromNewTimerVC() executes normally. The tableView just isn't updating to reflect it.
Here is my code:
import UIKit
class TimerListScreen: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tabelView: UITableView!
var timers = [Timer]()
let tableView = UITableView()
override func viewDidLoad() {
super.viewDidLoad()
tabelView.delegate = self
tabelView.dataSource = self
let tempTimer = Timer(timerLabel: "temp timer")
timers.append(tempTimer)
}
#IBAction func didUnwindFromNewTimerVC(_sender:UIStoryboardSegue){
guard let newTimerVC = _sender.source as? newTimerVC else{return}
newTimerVC.timer.setTimerLabel(timerLabel: newTimerVC.timerLabel.text!)
timers.append(newTimerVC.timer)
tableView.reloadData()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tabelView.dequeueReusableCell(withIdentifier: "TimerCell", for: indexPath) as? TimerCell{
let timer = timers[indexPath.row]
cell.updateUI(Timer: timer)
return cell
}else{
return UITableViewCell()
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return timers.count
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 78
}
}
Thank you
Please note the spelling. There are two table view instances: the outlet tabelView and a (pointless) instance tableView.
Reload the data of the outlet
tabelView.reloadData()
and delete the declaration line of the second instance let tableView ....
However I'd recommend to rename the outlet to correctly spelled tableView (you might need to reconnect the outlet in Interface Builder).
And force unwrap the cell
let cell = tabelView.dequeueReusableCell(withIdentifier: "TimerCell", for: indexPath) as! TimerCell
and remove the if - else part. The code must not crash if everything is hooked up correctly in IB.
I'm a newbie to Swift and XCode, taking a class in iOS development this summer. A lot of projects we're doing and examples I'm seeing for UI elements like PickerViews, TableViews, etc. are defining everything in the ViewController.swift file that acts as the controller for the main view. This works fine, but I'm starting to get to the point of project complexity where I'd really like all of my code to not be crammed into the same Swift file. I've talked to a friend who does iOS development on the side, he said this is sane and reasonable and well in-line with proper object-oriented programming... but I just can't seem to get it to work. Through trial and error I've gotten to this situation: the app runs in the simulator, the UITableView appears, but I'm not getting it populated with entries. I can get it working just fine when all the code is in the ViewController, but once I start trying to create a new controller class and make an instance of that class the dataSource/delegate of the UITableView I start getting nothing. I feel like I'm either missing some core understanding of Swift here, or doing something wrong with the Interface Builder in XCode.
My end result should be a UITableView with three entries in it; currently I'm getting a UITableView with no entries. I'm following along with a few different examples I've Googled, but primarily this other SO question: UITableView example for Swift
ViewController.swift:
import UIKit
class ViewController: UIViewController{
#IBOutlet var stateTableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
var viewController = StateViewController()
self.stateTableView.delegate = viewController
self.stateTableView.dataSource = viewController
}
}
StateViewController.swift:
import UIKit
class StateViewController: UITableViewController{
var states = ["Indiana", "Illinois", "Nebraska"]
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return states.count;
}
func tableView(cellForRowAttableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = UITableViewCell(style:UITableViewCellStyle.default, reuseIdentifier:"cell")
cell.textLabel?.text = states[indexPath.row]
return cell
}
}
In XCode I have the UITableView hooked up to the View Controller; the outlets are set to dataSource and delegate and the referencing outlet is stateTableView.
I'm not getting any errors; I do get a warning on my `var viewController = StateViewController()' statement in ViewController.swift where it wants me to use a constant, but switching it to a constant doesn't change the behavior (this is as it should be, I assume).
Originally I assumed that the error was in my StateViewController.swift file, where I'm not creating an object that adheres to the UITableViewDataSource or UITableViewDelegate protocol, but if I even add them into the class statement I immediately get errors like "Redundant conformance of 'StateViewController' to protocol 'UITableViewDataSource'" - I'm reading that this is because inheriting from UITableViewController automatically inherits the other protocols as well.
The last thing I tried was instead referring to self.states in the StateViewController's tableView functions, but I'm pretty sure self in Swift works the same as it does in Python and it feels like I'm just trying to add magic words at this point.
I've investigated as far as my currently-limited Swift knowledge can take me, so any answer that explains what I'm doing wrong rather than just telling me what to fix would be very appreciated.
Your issue is being caused by a memory management problem. You have the following code:
override func viewDidLoad() {
super.viewDidLoad()
var viewController = StateViewController()
self.stateTableView.delegate = viewController
self.stateTableView.dataSource = viewController
}
Think about the lifetime of the viewController variable. It ends when the end of viewDidLoad is reached. And since a table view's dataSource and delegate properties are weak, there is no strong reference to keep your StateViewController alive once viewDidLoad ends. The result, due to the weak references, is that the dataSource and delegate properties of the table view revert back to nil after the end of viewDidLoad is reached.
The solution is to create a strong reference to your StateViewController. Do this by adding a property to your view controller class:
class ViewController: UIViewController{
#IBOutlet var stateTableView: UITableView!
let viewController = StateViewController()
override func viewDidLoad() {
super.viewDidLoad()
self.stateTableView.delegate = viewController
self.stateTableView.dataSource = viewController
}
}
Now your code will work.
Once you get that working, review the answer by Ahmed F. There is absolutely no reason why your StateViewController class should be a view controller. It's not a view controller in any sense. It's simply a class that implements the table view data source and delegate methods.
Although I find it more readable and understandable to implement dataSource/delegate methods in the same viewcontroller, what are you trying to achive is also valid. However, StateViewController class does not have to be a subclass of UITableViewController (I think that is the part that you are misunderstanding it), for instance (adapted from another answer for me):
import UIKit
// ViewController File
class ViewController: UIViewController {
var handler: Handler!
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
handler = Handler()
tableView.dataSource = handler
}
}
Handler Class:
import UIKit
class Handler:NSObject, UITableViewDataSource {
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("myCell")
cell?.textLabel?.text = "row #\(indexPath.row + 1)"
return cell!
}
}
You can also use adapter to resolve this with super clean code and easy to understand, Like
protocol MyTableViewAdapterDelegate: class {
func myTableAdapter(_ adapter:MyTableViewAdapter, didSelect item: Any)
}
class MyTableViewAdapter: NSObject {
private let tableView:UITableView
private weak var delegate:MyTableViewAdapterDelegate!
var items:[Any] = []
init(_ tableView:UITableView, _ delegate:MyTableViewAdapterDelegate) {
self.tableView = tableView
self.delegate = delegate
super.init()
tableView.dataSource = self
tableView.delegate = self
tableView.rowHeight = UITableViewAutomaticDimension
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
}
func setData(data:[Any]) {
self.items = data
reloadData()
}
func reloadData() {
tableView.reloadData()
}
}
extension MyTableViewAdapter: UITableViewDataSource, UITableViewDelegate {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = "Hi im \(indexPath.row)"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
delegate?.myTableAdapter(self, didSelect: items[indexPath.row])
}
}
Use Plug and Play
class ViewController: UIViewController, MyTableViewAdapterDelegate {
#IBOutlet var stateTableView: UITableView!
var myTableViewAdapter:MyTableViewAdapter!
override func viewDidLoad() {
super.viewDidLoad()
myTableViewAdapter = MyTableViewAdapter(stateTableView, self)
}
func myTableAdapter(_ adapter: MyTableViewAdapter, didSelect item: Any) {
print(item)
}
}
You are trying to set datasource and delegate of UITableView as UITableViewController. As #Ahmad mentioned its more understandable in same class i.e. ViewController, you can take clear approach separating datasource and delegate of UITableView from UIViewController. You can make subclass of NSObject preferably and use it as datasource and delgate class of your UITableView.
You can also also use a container view and embed a UITableViewController. All your table view code will move to your UITableViewController subclass.Hence seprating your table view logic from your View Controller
Hope it helps. Happy Coding!!
The way I separate those concerns in my projects, is by creating a class to keep track of the state of the app and do the required operations on data. This class is responsible for getting the actual data (either creating it hard-coded or getting it from the persistent store). This is a real example:
import Foundation
class CountriesStateController {
private var countries: [Country] = [
Country(name: "United States", visited: true),
Country(name: "United Kingdom", visited: false),
Country(name: "France", visited: false),
Country(name: "Italy", visited: false),
Country(name: "Spain", visited: false),
Country(name: "Russia", visited: false),
Country(name: "Moldova", visited: false),
Country(name: "Romania", visited: false)
]
func toggleVisitedCountry(at index: Int) {
guard index > -1, index < countries.count else {
fatalError("countryNameAt(index:) - Error: index out of bounds")
}
let country = countries[index]
country.visited = !country.visited
}
func numberOfCountries() -> Int {
return countries.count
}
func countryAt(index: Int) -> Country {
guard index > -1, index < countries.count else {
fatalError("countryNameAt(index:) - Error: index out of bounds")
}
return countries[index]
}
}
Then, I create separate classes that implement the UITableViewDataSource and UITableViewDelegate protocols:
import UIKit
class CountriesTableViewDataSource: NSObject {
let countriesStateController: CountriesStateController
let tableView: UITableView
init(stateController: CountriesStateController, tableView: UITableView) {
countriesStateController = stateController
self.tableView = tableView
self.tableView.register(UITableViewCell.self, forCellReuseIdentifier: "UITableViewCell")
super.init()
self.tableView.dataSource = self
}
}
extension CountriesTableViewDataSource: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// return the number of items in the section(s)
return countriesStateController.numberOfCountries()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// return a cell of type UITableViewCell or another subclass
let cell = tableView.dequeueReusableCell(withIdentifier: "UITableViewCell", for: indexPath)
let country = countriesStateController.countryAt(index: indexPath.row)
let countryName = country.name
let visited = country.visited
cell.textLabel?.text = countryName
cell.accessoryType = visited ? .checkmark : .none
return cell
}
}
import UIKit
protocol CountryCellInteractionDelegate: NSObjectProtocol {
func didSelectCountry(at index: Int)
}
class CountriesTableViewDelegate: NSObject {
weak var interactionDelegate: CountryCellInteractionDelegate?
let countriesStateController: CountriesStateController
let tableView: UITableView
init(stateController: CountriesStateController, tableView: UITableView) {
countriesStateController = stateController
self.tableView = tableView
super.init()
self.tableView.delegate = self
}
}
extension CountriesTableViewDelegate: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("Selected row at index: \(indexPath.row)")
tableView.deselectRow(at: indexPath, animated: false)
countriesStateController.toggleVisitedCountry(at: indexPath.row)
tableView.reloadRows(at: [indexPath], with: .none)
interactionDelegate?.didSelectCountry(at: indexPath.row)
}
}
And this is how easy is to use them from the ViewController class now:
import UIKit
class ViewController: UIViewController, CountryCellInteractionDelegate {
public var countriesStateController: CountriesStateController!
private var countriesTableViewDataSource: CountriesTableViewDataSource!
private var countriesTableViewDelegate: CountriesTableViewDelegate!
private lazy var countriesTableView: UITableView = createCountriesTableView()
func createCountriesTableView() -> UITableView {
let tableViewOrigin = CGPoint(x: 0, y: 0)
let tableViewSize = view.bounds.size
let tableViewFrame = CGRect(origin: tableViewOrigin, size: tableViewSize)
let tableView = UITableView(frame: tableViewFrame, style: .plain)
return tableView
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
guard countriesStateController != nil else {
fatalError("viewDidLoad() - Error: countriesStateController was not injected")
}
view.addSubview(countriesTableView)
configureCountriesTableViewDelegates()
}
func configureCountriesTableViewDelegates() {
countriesTableViewDataSource = CountriesTableViewDataSource(stateController: countriesStateController, tableView: countriesTableView)
countriesTableViewDelegate = CountriesTableViewDelegate(stateController: countriesStateController, tableView: countriesTableView)
countriesTableViewDelegate.interactionDelegate = self
}
func didSelectCountry(at index: Int) {
let country = countriesStateController.countryAt(index: index)
print("Selected country: \(country.name)")
}
}
Note that ViewController didn't create the countriesStateController object, so it must be injected. We can do that from the Flow Controller, from the Coordinator or Presenter, etc. I did it from AppDelegate like so:
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
let countriesStateController = CountriesStateController()
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
if let viewController = window?.rootViewController as? ViewController {
viewController.countriesStateController = countriesStateController
}
return true
}
/* ... */
}
If it's never injected - we get a runt-time crash, so we know we must fix it straight away.
This is the Country class:
import Foundation
class Country {
var name: String
var visited: Bool
init(name: String, visited: Bool) {
self.name = name
self.visited = visited
}
}
Note how clean and slim the ViewController class is. It's less than 50 lines, and if create the table view from Interface Builder - it becomes 8-9 lines smaller.
ViewController above does what it's supposed to do, and that's to be a mediator between View and Model objects. It doesn't really care if the table displays one type or many types of cells, so the code to register the cell(s) belongs to CountriesTableViewDataSource class, which is responsible to create each cell as needed.
Some people combine CountriesTableViewDataSource and CountriesTableViewDelegate in one class, but I think it breaks the Single Responsibility Principle. Those two classes both need access to the same DataProvider / State Controller object, and ViewController needs access to that as well.
Note that View Controller had now way to know when didSelectRowAt was called, so we needed to create an additional protocol inside UITableViewDelegate:
protocol CountryCellInteractionDelegate: NSObjectProtocol {
func didSelectCountry(at index: Int)
}
And we also need a delegate property to make the communication possible:
weak var interactionDelegate: CountryCellInteractionDelegate?
Note that neither CountriesTableViewDataSource not CountriesTableViewDelegate class knows about the existence of the ViewController class. Using Protocol-Oriented-Programming - we could even remove the tight-coupling between those two classes and the CountriesStateController class.