I have searched answers in stackoverflow and none of them matches my needs. I am creating time tracking app on Swift Cocoa macOS, like Hubstaff time tracking app. At the moment runs a timer and I want to detect user's inactivity after x period of time and to send a Notification that he has been Idle x period of time. I'm new to iOS and macOS development. Can I have an example of how to do it?
Here is my code:
import Cocoa
class ViewController: NSViewController {
#IBOutlet weak var label: NSTextField!
#IBOutlet weak var playImage: NSButton!
var timer : Timer!
var isTimerWorking : Bool = false
var startTime : Date!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func playPause(_ sender: NSButton) {
if isTimerWorking {
endTimer()
playImage.image = NSImage(named: NSImage.Name("play"))
sender.state = .off
} else {
startTimer()
playImage.image = NSImage(named: NSImage.Name("stop"))
sender.state = .off
}
}
func startTimer() {
startTime = Date()
timer = Timer.scheduledTimer(
timeInterval: 1.0,
target: self,
selector: #selector(self.timerCounter),
userInfo: nil,
repeats: true
)
isTimerWorking = true
}
func endTimer() {
if timer != nil {
timer.invalidate()
label.stringValue = "00:00:00"
}
isTimerWorking = false
}
#objc func timerCounter() {
let currentTime = Date().timeIntervalSince(startTime)
let hour = Int(fmod(currentTime/3600, 60))
let minute = Int(fmod(currentTime/60, 60))
let second = Int(fmod(currentTime, 60))
let hourValue = String(format:"%02d", hour)
let minuteValue = String(format:"%02d", minute)
let secondValue = String(format:"%02d", second)
label.stringValue = "\(hourValue):\(minuteValue):\(secondValue)"
}
}
In my own time tracking app I am using
var lastEvent:CFTimeInterval = 0
lastEvent = CGEventSource.secondsSinceLastEventType(CGEventSourceStateID.hidSystemState, eventType: CGEventType(rawValue: ~0)!)
print(lastEvent)
to get the user idle time.
Related
So I'm trying to make a chess timer. I'm using string to make the 00:00 in a variable called storeTimed. Is there a way possible to make that used an timer to count down from that?
Here's my code:
The part I need help with is the updateTimer() function. Since the storedTime is a string trying to pass as a Int, xCode isn't liking it. I'm honestly not very sure what I could do. Mostly at the else statement, but the whole part in general
class ChessTimer: UIViewController {
#IBOutlet weak var playerTimer1: UILabel!
#IBOutlet weak var playerTimer2: UILabel!
var timer = Timer()
var time = 10
var isTimerRunning = false
var storedTime = "00:00"
override func viewDidLoad() {
super.viewDidLoad()
if isTimerRunning == false {
runTimer()
}
}
#IBAction func restartButton(_ sender: UIButton) {
}
#IBAction func pausePressed(_ sender: UIButton) {
timer.invalidate()
}
#IBAction func settingsPressed(_ sender: UIButton) {
performSegue(withIdentifier: "goToSettings", sender: self)
}
func runTimer() {
timer = Timer.scheduledTimer(timeInterval: 1, target: self,selector: (#selector(ChessTimer.updateTimer)),userInfo: nil, repeats: true)
isTimerRunning = true
}
#objc func updateTimer() {
if Int(storedTime) < 1 {
timer.invalidate()
playerTimer1.text = "00:00"
playerTimer2.text = "00:00"
}
else {
Int(storedTime)! -= 1
playerTimer1.text = prodTimeString(time: TimeInterval(storedTime)!)
}
}
func prodTimeString(time: TimeInterval) -> String {
let prodMinutes = Int(time) / 60 % 60
let prodSeconds = Int(time) % 60
return String(format: "%02d:%02d", prodMinutes, prodSeconds)
}
#IBAction func playerButton1(_ sender: UIButton) {
}
#IBAction func playerButton2(_ sender: UIButton) {
}
#IBAction func unwindToVC1(sender: UIStoryboardSegue) {
if let settingsController = sender.source as? SettingsController {
playerTimer1.text = settingsController.storedTime
playerTimer2.text = settingsController.storedTime
storedTime = settingsController.storedTime
}
}
}
To keep things simple, here's the code. I have removed the functions that aren't relevant to the discussion - non-implemented buttons, etc.,
The simple idea is that you use numbers (Int / Double / whatever) to store variables that you are counting with, and then have helper functions to present the variable in different formats
import UIKit
class ChessTimer: UIViewController {
var timer = Timer()
var isTimerRunning = false
var storedTime : Int = 0 // use an integer to store the time
override func viewDidLoad() {
super.viewDidLoad()
if isTimerRunning == false {
runTimer()
}
}
func runTimer() {
timer = Timer.scheduledTimer(timeInterval: 1, target: self,selector: (#selector(ChessTimer.updateTimer)),userInfo: nil, repeats: true)
isTimerRunning = true
}
#objc func updateTimer() {
// because we're storing the value in an Int, we don't need to convert it here
storedTime -= 1
if storedTime < 1 {
timer.invalidate()
// use the helper function to format the result for zero time as well as everything else
// that way, if you ever change it, you only have to change in one place
playerTimer1.text = prodTimeString(0)
playerTimer2.text = prodTimeString(0)
}
else {
playerTimer1.text = prodTimeString(storedTime)
}
}
func prodTimeString(_ time: Int) -> String {
// because there's only one parameter, and it's obvious, add '_' then you don't need the label when you call it
let prodMinutes = time / 60 % 60
let prodSeconds = time % 60
return String(format: "%02d:%02d", prodMinutes, prodSeconds)
}
}
I've been struggling to figure this out for a few days: I need to create a timer that the user can't kill, so once they start it, even if they kill the app or it enters background, it will pick up where it left off, and to achieve this I am saving the date when the app terminated and then calculating the difference, so that part works fine.
The problem I keep running into however is that a second timer seems to start if I minimise the app and bring it back. I'm not sure how timers are managed in the background, but nothing of what I tried (calling timer.invalidate() when applicationWillResignActive gets called, calling it in deinit() ) seems to work. The behaviour I see after this is that the timer will count like this: 80 - 78 - 79 - 76 - 77..
There's also a problem where the timer will sometime run past the time it's supposed to run for after killing the app, but I can't find the exact cause for that because it doesn't always happen.
Any idea what I'm doing wrong?
Thanks a lot.
class Focus: UIViewController {
// MARK: Variables
var timer = Timer()
let timeToFocus = UserDefaults.standard.double(forKey: "UDTimeToFocus")
let currentFocusedStats = UserDefaults.standard.integer(forKey: "UDFocusStats")
// MARK: Outlets
#IBOutlet weak var progress: KDCircularProgress!
#IBOutlet weak var timeLabel: UILabel!
#IBOutlet weak var focusTimeLabel: UILabel!
#IBOutlet weak var stepNameLabel: UILabel!
#IBOutlet weak var focusAgain: UIButton!
#IBOutlet weak var allDone: UIButton!
#IBOutlet weak var help: UIButton!
#IBOutlet weak var dottedCircle: UIImageView!
// MARK: Outlet Functions
#IBAction func helpTU(_ sender: Any) { performSegue(withIdentifier: "ToFocusingHelp", sender: nil) }
#IBAction func helpTD(_ sender: Any) { help.tap(shape: .rectangle) }
#IBAction func allDoneTU(_ sender: Any) {
UserDefaults.standard.set(false, forKey: "UDFocusIsRunning")
UserDefaults.standard.set(false, forKey: "UDShouldStartFocus")
completeSession()
hero(destination: "List", type: .zoomOut)
}
#IBAction func allDoneTD(_ sender: Any) { allDone.tap(shape: .rectangle) }
#IBAction func focusAgainTU(_ sender: Any) {
UserDefaults.standard.set(currentFocusedStats + Int(timeToFocus), forKey: "UDFocusStats")
UserDefaults.standard.set(true, forKey: "UDShouldStartFocus")
initFocus()
}
#IBAction func focusAgainTD(_ sender: Any) { focusAgain.tap(shape: .rectangle) }
// MARK: Class Functions
#objc func initFocus() {
var ticker = 0.0
var angle = 0.0
var duration = 0.0
if UserDefaults.standard.bool(forKey: "UDShouldStartFocus") == true {
UserDefaults.standard.set(Date(), forKey: "UDFocusStartDate")
UserDefaults.standard.set(false, forKey: "UDShouldStartFocus")
ticker = timeToFocus
duration = timeToFocus
angle = 0.0
print("starting")
} else {
let elapsedTime = difference(between: UserDefaults.standard.object(forKey: "UDFocusStartDate") as! Date, and: Date())
let timeLeft = timeToFocus - elapsedTime
ticker = timeLeft
duration = timeLeft
angle = elapsedTime / (timeToFocus / 360)
}
// Timer
let timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { timer in
if ticker > 0 {
self.timeLabel.text = "\(Int(ticker))s"
ticker -= 1
}
}
timer.fire()
// Progress Circle
progress.animate(fromAngle: angle, toAngle: 360, duration: duration) { completed in
if completed { self.completeSession() }
}
// UI Changes
allDone.isHidden = true
focusAgain.isHidden = true
help.isHidden = false
}
func completeSession() {
// The timer gets fired every time, but this will invalidate it if it's complete
timer.invalidate()
timeLabel.text = "Done"
help.isHidden = true
allDone.isHidden = false
focusAgain.isHidden = false
}
// MARK: viewDidLoad
override func viewDidLoad() {
initFocus()
allDone.isHidden = true
focusAgain.isHidden = true
if timeToFocus < 3600 { focusTimeLabel.text = "Focusing for \(Int(timeToFocus/60)) minutes" }
else if timeToFocus == 3600 { focusTimeLabel.text = "Focusing for \(Int(timeToFocus/60/60)) hour" }
else { focusTimeLabel.text = "Focusing for \(Int(timeToFocus/60/60)) hours" }
stepNameLabel.text = UserDefaults.standard.string(forKey: "UDSelectedStep")
// This resumes the timer when the user sent the app in the background.
NotificationCenter.default.addObserver(self, selector: #selector(self.initFocus), name: NSNotification.Name(rawValue: "WillEnterForeground"), object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.fadeProgress), name: NSNotification.Name(rawValue: "WillEnterForeground"), object: nil)
}
#objc func fadeProgress(){
// This function is called both when the view will enter foreground (for waking the phone or switching from another app) and on viewWillAppear (for starting the app fresh). It will fade the progress circle and buttons to hide a flicker that occurs.
timeLabel.alpha = 0
dottedCircle.alpha = 0
progress.alpha = 0
allDone.alpha = 0
focusAgain.alpha = 0
DispatchQueue.main.asyncAfter(deadline: .now() + 0.2, execute: {
UIButton.animate(withDuration: 0.5, animations: {
self.timeLabel.alpha = 1
self.dottedCircle.alpha = 1
self.progress.alpha = 1
self.allDone.alpha = 1
self.focusAgain.alpha = 1
})
})
}
// MARK: viewWillAppear
override func viewWillAppear(_ animated: Bool) { fadeProgress() }
}
It seems the problem is that you create a local timer variable inside initFocus() but you call invalidate inside completeSession for another timer defined there:
class Focus: UIViewController {
// MARK: Variables
var timer = Timer()
I developing a timer app for an apple watch.
I have two different Views at the moment. One with the actual timer (TimerController) and another with a pause-button (SwipeController).
I'm trying to stop/start the timer in the TimerController with the action from the button in the SwipeController.
Problem is that the timer stops, but the timer will not start again after hitting the button the second time.
If I press the button one time, the timer stops. If i press it again two times the timer will start again but will not stop when hitting the button again.
Any ideas of what the problem could be?
TimeController
import WatchKit
import Foundation
import UserNotifications
class TimerController: WKInterfaceController {
#IBOutlet weak var timerOutlet: WKInterfaceTimer! //
#IBOutlet weak var simple_timer_label: WKInterfaceLabel!
var myTimer : Timer?
var duration : TimeInterval = 1 //arbitrary number. 1 seconds
var isPaused = false //flag to determine if it is paused or not
var elapsedTime : TimeInterval = 0.0 //time that has passed between
var number_as_a_timer:Int = 0
var startTime = NSDate()
var dim_date = Date()
var current_minute: Int = 0
var current_hour: Int = 0
var curent_second: Int = 0
var seperate_is_paused_bool: Bool = false
override func awake(withContext context: Any?) {
super.awake(withContext: context)
start_timer()
}
func timeString(time:TimeInterval) -> String {
let hours: Int = Int(time) / 3600
let minutes: Int = Int(time) / 60 % 60
let seconds: Int = Int(time) % 60
let com = NSDateComponents()
com.minute = minutes
com.second = seconds
com.hour = hours
dim_date = NSCalendar.current.date(from: com as
DateComponents)!
self.timerOutlet.setDate(dim_date)
self.timerOutlet.start()
return String(format:"%02i:%02i:%02i", hours, minutes, seconds)
}
func start_timer() {
myTimer = Timer.scheduledTimer(timeInterval: duration, target:
self,selector: #selector(timerDone), userInfo: nil, repeats:
true)
}
#objc private func timerDone(){
//timer done counting down
if !isPaused {
number_as_a_timer += 1
let output:String = self.timeString(time:
TimeInterval(number_as_a_timer))
self.simple_timer_label.setText(output)
print(output)
}
}
override func willActivate() {
super.willActivate()
NotificationCenter.default.addObserver(self, selector:
#selector(stop_timer(notification:)), name: .stopTimer, object:
nil)
}
#objc func stop_timer(notification:NSNotification) {
// Timer is paused. so unpause it and resume countdown
if isPaused {
myTimer = Timer.scheduledTimer(timeInterval: 1,
target:self, selector: #selector(timerDone), userInfo: nil,
repeats: true)
self.isPaused = false
print("timer paused: resumming1")
} else {
isPaused = true
print("stoping timer")
//get how much time has passed before they paused it
let paused = NSDate()
elapsedTime += paused.timeIntervalSince(startTime as Date)
//stop watchkit timer on the screen
timerOutlet.stop()
//stop the ticking of the internal timer
myTimer!.invalidate()
}
}
}
extension Notification.Name {
static let stopTimer = Notification.Name("stopTimer")
}
SwipeController
import WatchKit
import Foundation
import UserNotifications
class SwipeController: WKInterfaceController {
//#IBOutlet weak var myTimer: WKInterfaceTimer!
var timer = TimerController()
var status: Bool = false
override func awake(withContext context: Any?) {
super.awake(withContext: context)
}
#IBAction func PauseButton() {
if timer.myTimer == nil {
print("timer is nil or invalidated")
print("Y: \(timer.isPaused)")
let userInfo = ["stop": true] as [String: Bool] // you
could also transfer data
NotificationCenter.default.post(name: .stopTimer, object:
nil, userInfo: userInfo)
} else {
print("empty block")
}
}
}
it looks like you aren't ever actually checking for you isPaused boolean to be true or false in your if statement when checking if your timer is paused.
if isPaused { <-----------
myTimer = Timer.scheduledTimer(timeInterval: 1,
target:self, selector: #selector(timerDone), userInfo: nil,
repeats: true)
self.isPaused = false
print("timer paused: resumming1")
The idea is simple and I do not think that the question has been asked in the past.
I want to build a simple mp3 player.
some songs displayed in a collection view the user selects a song
segue to another view with options to play, pause or stop only issue
is when you go back to the home screen to select a new song with the
current still playing. It is impossible to deactivate the current
player. When you need to play the 2 songs, the 2 are playing together
I have tried a lot of things
- create a new instance of player (player = AVAudioPlayer())
- player.pause() and player.play()
I do not see what I am doing wrong really.
this is my code :
import UIKit
import AVFoundation
class LecteurViewController: UIViewController {
var chansonSelected: Chanson? = nil
var lecteur:AVAudioPlayer = AVAudioPlayer()
var timer1 = Timer()
var timer2 = Timer()
#IBOutlet weak var dureeChansonSlider: UISlider!
#IBOutlet weak var chansonImageView: UIImageView!
#IBOutlet weak var chansonVolumeSlider: UISlider!
#IBOutlet weak var debutLabel: UILabel!
#IBOutlet weak var finLabel: UILabel!
#IBAction func stopMusicAction(_ sender: UIBarButtonItem) {
var player = AVAudioPlayer()
lecteur.stop()
LecteurManager.isActive = false
}
#IBAction func pauseMusicAction(_ sender: UIBarButtonItem) {
var player = AVAudioPlayer()
lecteur.pause()
LecteurManager.isActive = false
}
#IBAction func jouerMusicAction(_ sender: UIButton) {
if LecteurManager.isActive {
changeSong()
print("lecteur déjà en cours")
} else {
var player = AVAudioPlayer()
lecteur.play()
}
print(LecteurManager.isActive )
LecteurManager.isActive = true
}
func changeSong() {
lecteur.stop()
//lecteur = AVAudioPlayer()
jouerLecteurMp3()
print(chansonSelected!)
lecteur.play()
}
override func viewDidLoad() {
super.viewDidLoad()
configureView()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
jouerLecteurMp3()
}
func configureView() {
self.title = (chansonSelected!.titre!).capitalized
chansonImageView.image = UIImage(named: "\(chansonSelected!.image).jpgs")
//formatter 'back' button
let backBtn = UIBarButtonItem(title: "< Playlist", style: .plain, target: self, action: #selector(LecteurViewController.reset(_sender:)))
self.navigationItem.leftBarButtonItem = backBtn
self.navigationController?.navigationBar.tintColor = UIColor.white
//contrôler volume chanson
chansonVolumeSlider.addTarget(self, action: #selector(LecteurViewController.ajusterVolume(_ :)), for: UIControlEvents.valueChanged)
//contrôler durée chanson
dureeChansonSlider.addTarget(self, action: #selector(LecteurViewController.ajusterDurée(_ :)), for: UIControlEvents.valueChanged)
updateUI()
}
func updateUI() {
//indiquer position chanson
timer1 = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(LecteurViewController.mettreAJourDurée), userInfo: nil, repeats: true)
//afficher durée chanson
timer2 = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(LecteurViewController.afficherDurée), userInfo: nil, repeats: true)
}
func reset(_sender:UIBarButtonItem) {
self.navigationController?.popViewController(animated: true)
}
func ajusterVolume(_ sender:UISlider) {
//print("volume ajusté \(chansonVolumeSlider.value)")
lecteur.volume = chansonVolumeSlider.value
}
func ajusterDurée(_ sender:UISlider) {
lecteur.currentTime = TimeInterval(dureeChansonSlider.value)
}
func mettreAJourDurée() {
dureeChansonSlider.value = Float(lecteur.currentTime)
}
func afficherDurée() {
print("durée actuelle: \(lecteur.duration - lecteur.currentTime)")
debutLabel.text = retournerPositionActuelle()
finLabel.text = retournerDureeTotal()
}
func retournerPositionActuelle() -> String {
let seconds = Int(lecteur.currentTime) % 60
let minutes = (Int(lecteur.currentTime) / 60) % 60
return String(format: "%0.2i:%0.2i", minutes, seconds)
}
func retournerDureeTotal() -> String {
let seconds = Int(lecteur.currentTime) % 60
let minutes = (Int(lecteur.currentTime) / 60) % 60
return String(format: "%0.2i:%0.2i", minutes, seconds)
}
func jouerLecteurMp3() {
let chanson = "bensound-\(chansonSelected!.titre!)"
let fichierMp3 = Bundle.main.path(forResource: chanson, ofType: "mp3")
do {
try lecteur = AVAudioPlayer(contentsOf: URL(string: fichierMp3!)!)
dureeChansonSlider.maximumValue = Float(lecteur.duration)
} catch {
print("erreur lecture mp3")
}
}
}
Try this:
func reset(_sender:UIBarButtonItem)
{
self.navigationController?.popViewController(animated: true)
lecteur.stop()
}
I want my countdown timer to suspend and then resume when the app leaves / returns to focus, using the time away to calculate how much time should be deducted.
I am using the app delegate file (not sure thats the right location? or if they are meant to be in the view controllers file as functions of their own?)
Issue is im getting a lot of errors such as:
Value of type 'AppDelegate' has no member 'restTimer'
Use of unresolved identifier 'nextFireDate'
Use of unresolved identifier 'selector'
restTimer was declared as a timer in my view controllers file but when i tried these blocks in that file i got an equal number of errors for unresolved identifiers
and using the following 2 code blocks
func applicationWillResignActive(_ application: UIApplication) {
guard let t = self.restTimer else { return }
nextFireDate = t.fireDate
t.invalidate()
and
func applicationDidBecomeActive(_ application: UIApplication) {
guard let n = nextFireDate else { return }
let howMuchLonger = n.timeIntervalSinceDate(NSDate())
if howMuchLonger < 0 {
print("Should have already fired \(howMuchLonger) seconds ago")
target!.performSelector(selector!)
} else {
print("should fire in \(howMuchLonger) seconds")
Timer.scheduledTimerWithTimeInterval(howMuchLonger, target: target!, selector: selector!, userInfo: nil, repeats: false)
}
}
UPDATE: Added full views code due to issue incorporating the answer
import Foundation
import UIKit
class RestController: UIViewController {
#IBOutlet weak var restRemainingCountdownLabel: UILabel!
#IBOutlet weak var setsRemainingCountdownLabel: UILabel!
#IBOutlet weak var numberOfSetsLabel: UILabel!
#IBOutlet weak var numberOfRestLabel: UILabel!
#IBOutlet weak var adjustSetsStepper: UIStepper!
#IBOutlet weak var adjustRestStepper: UIStepper!
var startDate: Date!
let startDateKey = "start.date"
let interval = TimeInterval(20)
var restTimer: Timer!
var restCount = 0
var setCount = 0
var selectedTime = 1
var selectedSets = 1
private let resignDateKey = "resign.date"
#IBAction func endSetPressed(_ sender: Any) {
if (setCount > 0){
setCount -= 1
setsRemainingCountdownLabel.text = String(setCount)
}
handleTimer()
}
#IBAction func setStepperValueChanged(_ sender: UIStepper) {
numberOfSetsLabel.text = Int(sender.value).description
self.setCount = Int(sender.value)
self.selectedSets = setCount
setsRemainingCountdownLabel.text = String(setCount)
}
#IBAction func restStepperValueChanged(_ sender: UIStepper) {
numberOfRestLabel.text = Int(sender.value).description
let timeMinSec = timeFormatted(totalSeconds: Int(sender.value)*60)
restRemainingCountdownLabel.text = timeMinSec
self.selectedTime = Int(sender.value)
restCount = self.selectedTime * 60
}
#IBAction func resetSetsButton(_ sender: Any) {
setCount = Int(adjustSetsStepper.value)
setsRemainingCountdownLabel.text = String(setCount)
}
override func viewDidLoad() {
super.viewDidLoad()
numberOfSetsLabel.text = String(selectedSets)
numberOfRestLabel.text = String(selectedTime)
createTimer(interval: interval)
NotificationCenter.default.addObserver(self, selector: #selector(willResignActive), name: NSNotification.Name.UIApplicationWillResignActive, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(didBecomeActive), name: NSNotification.Name.UIApplicationDidBecomeActive, object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
#objc private func willResignActive(notification: Notification) {
print("resigning")
guard restTimer.isValid else {
UserDefaults.standard.removeObject(forKey: startDateKey)
return
}
restTimer.invalidate()
UserDefaults.standard.set(Date(), forKey: startDateKey)
}
#objc private func didBecomeActive(notification: Notification) {
print("resume")
if let startDate = UserDefaults.standard.object(forKey: startDateKey) as? Date {
let elapsed = -startDate.timeIntervalSinceNow
print("elpased time: \(elapsed) remaining time: \(interval - elapsed)")
if elapsed > interval {
timerUp()
} else {
createTimer(interval: interval - elapsed)
}
}
}
private func createTimer (interval: TimeInterval) {
restTimer = Timer.scheduledTimer(withTimeInterval: interval , repeats: false) {[weak self] _ in
self?.timerUp()
}
startDate = Date()
}
private func timerUp() {
print("At least \(interval) seconds has elapsed")
}
func handleSets() {
if (setCount > 0) {
self.restCount = self.selectedTime * 60
}
handleTimer()
}
func handleTimer() {
if (restTimer?.isValid ?? false) {
restTimer?.invalidate()
restTimer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(RestController.updateTimer), userInfo: nil, repeats: true)
} else {
restTimer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(RestController.updateTimer), userInfo: nil, repeats: true)
}
}
func updateTimer() {
if (restCount > 0){
restCount -= 1
} else if (restCount == 0){
restTimer?.invalidate()
}
restRemainingCountdownLabel.text = timeFormatted(totalSeconds: restCount)
}
func timeFormatted(totalSeconds: Int) -> String {
let seconds: Int = totalSeconds % 60
let minutes: Int = (totalSeconds / 60) % 60
return String(format: "%02d:%02d", minutes, seconds)
}
I think you cannot rely on the fact that the app will remain in memory while it is in the background. Thus, you should archive all the data you need to recreate the timer at the exact point.
For example, in applicationWillResignActive
UserDefaults.standard.set(value: t.nextFireDate forKey:"NextFireDate")
and in applicationWillEnterForeground
if let fireDate = UserDefaults.standard.object(forKey: "NextFireDate") {
// setup a timer with the correct fire date
}
You don't have to use the AppDelegate for this because it also posts notifications. You can use the AppDelegate if you want. Here is code using notifications:
class ViewController: UIViewController{
private let startDateKey = "start.date"
private let interval = TimeInterval(20)
private var startDate: Date!
private var timer: Timer!
override func viewDidLoad() {
super.viewDidLoad()
createTimer(interval: interval)
NotificationCenter.default.addObserver(self, selector: #selector(willResignActive), name: NSNotification.Name.UIApplicationWillResignActive, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(didBecomeActive), name: NSNotification.Name.UIApplicationDidBecomeActive, object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
#objc private func willResignActive(notification: Notification) {
print("resigning")
guard timer.isValid else {
UserDefaults.standard.removeObject(forKey: startDateKey)
return
}
timer.invalidate()
UserDefaults.standard.set(Date(), forKey: startDateKey)
}
#objc private func didBecomeActive(notification: Notification) {
print("resume")
if let startDate = UserDefaults.standard.object(forKey: startDateKey) as? Date {
let elapsed = -startDate.timeIntervalSinceNow
print("elpased time: \(elapsed) remaining time: \(interval - elapsed)")
if elapsed > interval {
timerUp()
} else {
createTimer(interval: interval - elapsed)
}
}
}
private func createTimer (interval: TimeInterval) {
timer = Timer.scheduledTimer(withTimeInterval: interval , repeats: false) {[weak self] _ in
self?.timerUp()
}
startDate = Date()
}
private func timerUp() {
print("At least \(interval) seconds has elapsed")
}
}