How to make a timer reset after button gesture in a different view controller? - swift

Question

I am developing a quiz app where the user is asked a question at random and must answer it on the initial view controller. If the user picks correctly, a second view controller appears which contains a button that pops the view controller off the navigation stack and goes back to the initial view controller to finish the other questions. However, I have a timer that I want to reset (start at 15s) every time that second view controller is popped and the initial view controller appears with the next question. How would I accomplish this task? I already have the countdown timer code in my swift file. I just need to know how to get it to start from scratch every time the second view controller is popped/removed.
Here's my code for the initial view controller:
import UIKit
extension ViewController: QuizCompletedDelegate {
func continueQuiz() {
randomQuestion()
}
}
class ViewController: UIViewController {
var questionList = [String]()
func updateCounter() {
counter -= 1
questionTimer.text = String(counter)
if counter == 0 {
timer.invalidate()
wrongSeg()
counter = 15
}
}
func randomQuestion() {
//random question
if questionList.isEmpty {
questionList = Array(QADictionary.keys)
}
let rand = Int(arc4random_uniform(UInt32(questionList.count)))
questionLabel.text = questionList[rand]
//matching answer values to go with question keys
var choices = QADictionary[questionList[rand]]!
questionList.remove(at: rand)
//create button
var button:UIButton = UIButton()
//variables
var x = 1
rightAnswerBox = arc4random_uniform(4)+1
for index in 1...4 {
button = view.viewWithTag(index) as! UIButton
if (index == Int(rightAnswerBox)) {
button.setTitle(choices[0], for: .normal)
} else {
button.setTitle(choices[x], for: .normal)
x += 1
}
randomImage()
}
}
let QADictionary = ["Who is Thor's brother?" : ["Atum", "Loki", "Red Norvell", "Kevin Masterson"], "What is the name of Thor's hammer?" : ["Mjolinr", "Uru", "Stormbreaker", "Thundara"], "Who is the father of Thor?" : ["Odin", "Sif", "Heimdall", "Balder"]]
//wrong view segue
func wrongSeg() {
performSegue(withIdentifier: "incorrectSeg", sender: self)
}
//proceed screen
func rightSeg() {
performSegue(withIdentifier: "correctSeg", sender: self)
}
//variables
var rightAnswerBox:UInt32 = 0
var index = 0
//Question Label
#IBOutlet weak var questionLabel: UILabel!
//Answer Button
#IBAction func buttonAction(_ sender: AnyObject) {
if (sender.tag == Int(rightAnswerBox)) {
rightSeg()
print ("Correct!")
}
if counter != 0 {
counter = 15
questionTimer.text = String(counter)
} else if (sender.tag != Int(rightAnswerBox)) {
wrongSeg()
print ("Wrong!")
timer.invalidate()
questionList = []
}
}
override func viewDidAppear(_ animated: Bool) {
randomQuestion()
}
//variables
var counter = 15
var timer = Timer()
#IBOutlet weak var questionTimer: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
timer = Timer.scheduledTimer(timeInterval: 1, target:self, selector: #selector(ViewController.updateCounter), userInfo: nil, repeats: true)
}
}
Here's the code to the second view controller:
class ContinueScreen: UIViewController {
var delegate: QuizCompletedDelegate?
//correct answer label
#IBOutlet weak var correctLbl: UILabel!
//background photo
#IBOutlet weak var backgroundImage: UIImageView!
func backToQuiz() {
delegate?.continueQuiz()
if let nav = self.navigationController {
nav.popViewController(animated: true)
} else {
self.dismiss(animated: true, completion: nil)
}
}
#IBAction func `continue`(_ sender: Any) {
backToQuiz()
}
override func viewDidLoad() {
super.viewDidLoad()
}
}

Answer 1

How to make countdown timer reset after button push on different view
controller?
So if you can get the reference of yourView controller where you have
setup the timer then you can access counter variable from previous
view controller inside your second viewController and when pushed the
button just reset to 0.
If above approach is not possible for you then another way is create
the static variable and access it anywhere and reset like this:-
static var counter = 0

Answer 2

if you are popping/removing the 2nd view controller and thus returning to the first, you could reset the timer in your viewDidAppearfunc in your 1st view controller. this way the timer restarts every time the view appears - the first time, and whenever the 2nd pops.