How to keep label results on secondViewController? - ios

Question

I am currently working on an app and I am stuck on the following: I have my mainVC (ReceiveInputVC), which after I enter an input, it goes to the secondVC (TimeLeftVC) and it updates all of its labels with results from the inputs received from the mainVC. My question is: How can I, after clicking on the arrow to go back to the mainVC or even if I close the app, when I click on the arrow from the mainVC to go to the secondVC have my labels showing the same values as before the user closed the application or returned to the main screen?
import UIKit
extension UIViewController {
func hideKeyboard() {
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(dismissKeyboard))
view.addGestureRecognizer(tap)
}
#objc func dismissKeyboard() {
view.endEditing(true)
}
}
class ReceiveInputVC: UIViewController {
#IBOutlet weak var hourglassButton: UIButton!
#IBOutlet weak var whatIsYourAgeField: UITextField!
#IBOutlet weak var ageToDieField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.hideKeyboard()
}
#IBAction func arrowBtnPressed(_ sender: Any) {
// When pressed should show go to TimeLeftVC and show last result from the first time user entered the inputs, if nothing has been typed yet and no data has been saved an alert should pop up asking the user to enter an input on both fields
}
#IBAction func hourglassBtnPressed(_ sender: Any) {
let checkAgeField: Int? = Int(whatIsYourAgeField.text!)
let checkDyingAgeField: Int? = Int(ageToDieField.text!)
if (whatIsYourAgeField.text == "" || ageToDieField.text == "") || (whatIsYourAgeField.text == "" && ageToDieField.text == "") {
alert(message: "You must enter an input on both fields")
} else if checkAgeField! < 1 || checkDyingAgeField! > 100 {
alert(message: "You must enter an age higher than 1 and a dying age lower than 100")
} else if (checkAgeField! > checkDyingAgeField!) || (checkAgeField! == checkDyingAgeField!) {
alert(message: "You must enter an age lower than a dying age")
} else {
performSegue(withIdentifier: "goToSecondScreen", sender: self)
}
}
func alert(message: String, title: String = "Alert") {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Try Again", style: UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
// Passing the data entered from ReceiveInputVC to TimeLeftVC
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToSecondScreen" {
let destinationTimeLeftVC = segue.destination as! TimeLeftVC
destinationTimeLeftVC.ageReceived = whatIsYourAgeField.text
destinationTimeLeftVC.ageToDieReceived = ageToDieField.text
}
}
}
import CircleProgressBar
class TimeLeftVC: UIViewController {
var ageReceived: String! // receive whatIsYourAgeField data from ReceiveInputVC
var ageToDieReceived: String! // receive ageToDieField data from ReceiveInputVC
#IBOutlet weak var yearsLeftLabel: UILabel!
#IBOutlet weak var daysLeftLabel: UILabel!
#IBOutlet weak var hoursLeftLabel: UILabel!
#IBOutlet weak var progressBar: CircleProgressBar!
override func viewDidLoad() {
super.viewDidLoad()
createResults()
}
func createResults() {
if let userAge = Int(ageReceived), let dyingAge = Int(ageToDieReceived) {
let yearsLeft = dyingAge - userAge
let daysLeft = yearsLeft * 365
let hoursLeft = daysLeft * 24
// Update UI
yearsLeftLabel.text = "\(yearsLeft)"
daysLeftLabel.text = "\(daysLeft)"
hoursLeftLabel.text = "\(hoursLeft)"
let percentage = (CGFloat(yearsLeft) / CGFloat(dyingAge)) * 100
let formatted = String(format: "%.1f", percentage)
// Update Circle Progress Bar
progressBar.setHintTextGenerationBlock { (progress) -> String? in
return String.init(format: "\(formatted)%%", arguments: [progress])
}
progressBar.setProgress(percentage/100, animated: true, duration: 4.0)
}
}
Project on GitHub: https://github.com/mvvieira95/Time-Life.git

Answer 1

You can use Coredata or another data base or user default
User default implementation:
#IBAction func arrowBtnPressed(_ sender: Any) {
UserDefaults.standard.set("your input values from text field or ...", forKey: "key")
}
In second view controller get it with
UserDefaults.standard.string(forKey: "key")

Answer 2

You can save and restore states with these methods
application:shouldSaveApplicationState and application:shouldRestoreApplicationStat.
Example:
func application(_ application: UIApplication,
shouldSaveApplicationState coder: NSCoder) -> Bool {
// Save the current app version to the archive.
coder.encode(11.0, forKey: "MyAppVersion")
// Always save state information.
return true
}
func application(_ application: UIApplication,
shouldRestoreApplicationState coder: NSCoder) -> Bool {
// Restore the state only if the app version matches.
let version = coder.decodeFloat(forKey: "MyAppVersion")
if version == 11.0 {
return true
}
// Do not restore from old data.
return false
}
You can explore the document in https://developer.apple.com/documentation/uikit/view_controllers/preserving_your_app_s_ui_across_launches?language=objc

Answer 3

Thanks guys, I came up with a solution:
class ReceiveInputVC: UIViewController {
#IBAction func arrowBtnPressed(_ sender: Any) {
let defaults = UserDefaults.standard
if let _ = defaults.object(forKey: "yearsSaved"), let _ = defaults.object(forKey: "daysSaved"), let _ = defaults.object(forKey: "hoursSaved") {
performSegue(withIdentifier: "goToSecondScreen", sender: self)
} else {
alert(message: "You must first enter an input")
}
}
class TimeLeftVC: UIViewController {
var ageReceived: String! // receive whatIsYourAgeField data from ReceiveInputVC
var ageToDieReceived: String! // receive ageToDieField data from ReceiveInputVC
#IBOutlet weak var yearsLeftLabel: UILabel!
#IBOutlet weak var daysLeftLabel: UILabel!
#IBOutlet weak var hoursLeftLabel: UILabel!
#IBOutlet weak var progressBar: CircleProgressBar!
override func viewDidLoad() {
super.viewDidLoad()
let defaults = UserDefaults.standard
yearsLeftLabel.text = defaults.object(forKey: "yearsSaved") as? String
daysLeftLabel.text = defaults.object(forKey: "daysSaved") as? String
hoursLeftLabel.text = defaults.object(forKey: "hoursSaved") as? String
}
override func viewWillAppear(_ animated: Bool) {
createResults()
}
func createResults() {
if let userAge = Int(ageReceived), let dyingAge = Int(ageToDieReceived) {
let yearsLeft = dyingAge - userAge
let daysLeft = yearsLeft * 365
let hoursLeft = daysLeft * 24
// Update UI
yearsLeftLabel.text = "\(yearsLeft)"
daysLeftLabel.text = "\(daysLeft)"
hoursLeftLabel.text = "\(hoursLeft)"
// Store Data
let defaults = UserDefaults.standard
defaults.set(yearsLeftLabel.text, forKey: "yearsSaved")
defaults.set(daysLeftLabel.text, forKey: "daysSaved")
defaults.set(hoursLeftLabel.text, forKey: "hoursSaved")
// Update Circle Progress Bar
let percentage = (CGFloat(yearsLeft) / CGFloat(dyingAge)) * 100
let formatted = String(format: "%.1f", percentage)
progressBar.setHintTextGenerationBlock { (progress) -> String? in
return String.init(format: "\(formatted)%%", arguments: [progress])
}
progressBar.setProgress(percentage/100, animated: true, duration: 4.0)
}
}
Having troubles now updating that progressBar when I go back to the view...