You can pass data via segues or protocols. Since you are using segues i will show you a complete example and how to do it the right way in Swift 3. Using only two ViewControllers.
- Create two
UITextFields in the main "ViewController".
- Create a new view controller of type
UIViewController call it "MainTabelViewController" and add a tableView in it. Select content Dynamic prototypes Style Grouped and create 1 prototype cell and add a UILabel to it for the city name. "Don't forget the put the cell identifier name". I called it "cell".
- Add the delegates and data sources to the class and add its functions like in code.
- Create a segue from the main view controller to the main table view controller. And create another segue the opposite direction. "Don't forget the put the segue identifier names" I called them "toCity" & "toMain"
- Create a "CityTableViewCell" controller of type
UITableViewCell and create an IBOutlet of UILabel type where you will save the city name in as a text.
Edit this part in the AppDelegate.swift To delete the city names saved using in the UserDefaults every time the app is launched. So i wont populate the UITextFields randomly every time.
import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
var userDefaults: UserDefaults!
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
userDefaults = UserDefaults.standard
userDefaults.removeObject(forKey: "City One")
userDefaults.removeObject(forKey: "City Two")
return true
}
This is the ordinary main ViewController.swift where you have your UITextFields in. I distinguish which UITextField did the user click on using the tags. You need to add also the UITextFieldDelegate protocol to be able to use the the textFieldDidBeginEditing function. And i also save the selected city names using UserDefaults class to call them when user chooses the other city.
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet var cityOneLabel: UITextField!
@IBOutlet var cityTwoLabel: UITextField!
@IBOutlet var continueButton: UIButton!
var selectedCityOne = ""
var selectedCityTwo = ""
var userDefaults: UserDefaults!
override func viewDidLoad() {
super.viewDidLoad()
cityOneLabel.delegate = self
cityTwoLabel.delegate = self
cityOneLabel.tag = 1
cityTwoLabel.tag = 2
continueButton.isEnabled = false
}
override func viewDidAppear(_ animated: Bool) {
userDefaults = UserDefaults.standard
cityOneLabel.text = selectedCityOne
cityTwoLabel.text = selectedCityTwo
if selectedCityOne != "" {
userDefaults.set(selectedCityOne, forKey: "City One")
} else {
cityOneLabel.text = userDefaults.string(forKey: "City One")
}
if selectedCityTwo != "" {
userDefaults.set(selectedCityTwo, forKey: "City Two")
} else {
cityTwoLabel.text = userDefaults.string(forKey: "City Two")
}
if cityOneLabel.text != "" && cityTwoLabel.text != "" {
continueButton.isEnabled = true
} else {
continueButton.isEnabled = false
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func continueButtonAction(_ sender: UIButton) {
//Later on continue after selecting the cities
}
func textFieldDidBeginEditing(_ textField: UITextField) {
performSegue(withIdentifier: "toCity", sender: textField.tag)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toCity" {
guard let cityVC = segue.destination as? MainTableViewController else {
return
}
cityVC.selectedTextField = sender as! Int
}
}
}
In the CityTabelViewCell.swift add the IBOutlet UILabel for the city name.
import UIKit
class CityTableViewCell: UITableViewCell {
@IBOutlet var cityNameLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
For the MainTabelViewController.swift write this:
Here is where i create an array of strings to populate my table view UILabels with.
import UIKit
class MainTableViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
@IBOutlet var cityTabelView: UITableView!
var cityNamesArray = ["Cairo", "Alexandria", "Suez"]
var selectedTextField = Int()
var selectedCityName = ""
override func viewDidLoad() {
super.viewDidLoad()
cityTabelView.delegate = self
cityTabelView.dataSource = self
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! CityTableViewCell
cell.cityNameLabel.text = cityNamesArray[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return cityNamesArray.count
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
selectedCityName = cityNamesArray[indexPath.row]
performSegue(withIdentifier: "toMain", sender: self)
}
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
var title = ""
if selectedTextField == 1 {
title = "City One"
} else if selectedTextField == 2 {
title = "City Two"
}
return title
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toMain" {
guard let mainVC = segue.destination as? ViewController else {
return
}
if selectedTextField == 1 {
mainVC.selectedCityOne = selectedCityName
} else if selectedTextField == 2 {
mainVC.selectedCityTwo = selectedCityName
}
}
}
}
This is how my layout looks like. Try it. I just added a continue button too if the user will have to go to another UIViewController after selecting the two cities.
