I want to have a looping event with a timer triggered instantly when a button is held down. But the timer function pauses for two seconds before auctioning the 'pulse', my (maybe slightly naive) assumption was the timer would pause after the action before starting the loop again.
Any idea how can I get the below to give the 2 second pause after the pulse instead of before?
#IBAction func flashDown(_ sender: Any) {
// Touch Down Button
Timer.scheduledTimer(withTimeInterval: 2, repeats: true) { timer in
print("Pulse")
}
}
You can use another initializer of Timer and add it to the RunLoop by yourself.
#IBAction func flashDown(_ sender: Any) {
let now = Date()
let timer = Timer(fire: now, interval: 2, repeats: true) { timer in
print("Pulse")
}
RunLoop.main.add(timer, forMode: .default)
}
The OOPer's answer is nice, but actually you can just call the fire method of the timer instance. This method can be called at any time without interrupting its regular firing schedule.
#IBAction func flashDown(_ sender: Any) {
// Touch Down Button
let timer = Timer.scheduledTimer(withTimeInterval: 2, repeats: true) { timer in
print("Pulse")
}
timer.fire()
}
I am creating a trivia app in swift and I have a timer that counts down each question. However as the user progresses with each question the timer speeds up. Can someone help me fix this?
My runGameTimer function:
func runGameTimer()
{
gameTimer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(RockTriviaViewController.updateGameTimer), userInfo: nil, repeats: true)
}
My updateGameTimer function:
#objc func updateGameTimer()
{
gameInt -= 1
timerLabel.text = String(gameInt)
if (gameInt == 0)
{
gameTimer.invalidate()
/*
if (currentQuestion != rockQuestions[questionSet].count)
{
newQuestion()
}
else
{
performSegue(withIdentifier: "showRockScore", sender: self)
}
*/
}
}
Where I call my code:
func newQuestion()
{
gameInt = 11
runGameTimer()
rockQuestion.text = rockQuestions[questionSet][currentQuestion]
rightAnswerPlacement = arc4random_uniform(3)+1
var Button: UIButton = UIButton()
var x = 1
for i in 1...3
{
Button = view.viewWithTag(i) as! UIButton
if(i == Int(rightAnswerPlacement))
{
Button.setTitle(rockAnswers[questionSet][currentQuestion][0], for: .normal)
}
else
{
Button.setTitle(rockAnswers[questionSet][currentQuestion][x], for: .normal)
x = 2
}
}
currentQuestion += 1
}
You're calling runGameTimer() in every call to newQuestion(). If a timer was already running then you'll add a new timer each time, and they will all call your selector. So if you have 3 timers running, your selector will be called 3x as often. That's not what you want.
Change your timer variable to be weak:
weak var gameTimer: Timer?
And then in runGameTimer invalidate the timer before creating a new one, using optional chaining:
func runGameTimer() {
gameTimer?.invalidate() //This will do nothing if gameTimer is nil.
//it will also cause the gameTimer to be nil since it's weak.
gameTimer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(RockTriviaViewController.updateGameTimer), userInfo: nil, repeats: true)
}
By making the game timer weak it will get set to nil as soon as it's invalidated. (When you schedule a timer the system retains it while it is running so it stays valid as long as it continues to run.)
By using optional chaining to reference the timer:
gameTimer?.invalidate()
The code doesn't do anything if gameTimer is nil.
I just started to learn swift . and I found when using a button to start a count down if i pressed the button twice it speeds up the process. What to add to prevent that?
#IBAction func startButton(_ sender: Any) {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(processTime), userInfo: nil, repeats: true)
}
#objc func processTime(){
if counter > 0 {
counter -= 1
timeLabel.text = "\(counter)"
}else {
timer.invalidate()
}
}
I tried to use sender.isEnabled = false it gave this error (Value of type 'Any' has no member 'isEnabled')
so I did it like this :
#IBAction func startButton(_ sender: Any) {
if timer.isValid != true{
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(processTime), userInfo: nil, repeats: true)
}
}
Many ways, depends on what logic you prefer.
Basically you need to ensure that the timer starts only once until it completes.
In the following example, we start the timer only if it's not been initialized previously.
Furthermore, when we stop the timer, we explicitly set it to nil so the following logic works again after the timer completes.
//globally declared as optional
var timer: Timer?
#IBAction func startButton(_ sender: Any) {
//check if timer is nil
if timer != nil {
//start timer only if timer is nil
timer = Timer.scheduledTimer(timeInterval: 1,
target: self,
selector: #selector(processTime),
userInfo: nil,
repeats: true)
}
}
#objc func processTime() {
if counter > 0 {
counter -= 1
timeLabel.text = "\(counter)"
}
else {
timer.invalidate()
//clear the timer
timer = nil
}
}
add a sender.isEnabled = false and after you press the button once it won't be clickable again
You need to invalidate the timer by calling timer.invalidate() before you reassign a new timer. If you assign a new timer instance to the old one without invalidating, you will lose reference to it and it will never be invalidated.
I have a timer variable in a function like this:
timer = NSTimer()
func whatever() {
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "timerbuiltingo", userInfo: nil, repeats: true)
}
when I try to stop the timer in the resulting timerbuiltingo function like this:
func timerbuiltingo() {
timer.invalidate()
self.timer.invalidate()
}
It doesn't stop it. How should I be doing this?
If you need to be able to stop the timer at any point in time, make it an instance variable.
If you will only ever need to stop it in the method it is called, you can have that method accept an NSTimer argument. The timer calling the method will pass itself in.
class ClassWithTimer {
var timer = NSTimer()
func startTimer() {
self.timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "timerTick:", userInfo: nil, repeats: true)
}
#objc func timerTick(timer: NSTimer) {
println("timer has ticked")
}
}
With this set up, we can now either call self.timer.invalidate() or, within timerTick, we can call timer.invalidate() (which refers to the timer which called the method).
I'm developing a game and I want to create a pause menu. Here is my code:
self.view?.paused = true
but NSTimer.scheduledTimerWithTimeInterval still running...
for var i=0; i < rocketCount; i++ {
var a: NSTimeInterval = 1
ii += a
delaysShow = 2.0 + ((stimulus + interStimulus) * ii)
var time3 = NSTimer.scheduledTimerWithTimeInterval(delaysShow!, target: self, selector: Selector("showRocket:"), userInfo: rocketid[i], repeats: false)
}
I want time3 to pause the timer when player click pause menu and continue run the timer when player come back to the game, but how can I pause NSTimer.scheduledTimerWithTimeInterval? help me please.
You need to invalidate it and recreate it. You can then use an isPaused bool to keep track of the state if you have the same button to pause and resume the timer:
var isPaused = true
var timer = NSTimer()
#IBAction func pauseResume(sender: AnyObject) {
if isPaused{
timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: Selector("somAction"), userInfo: nil, repeats: true)
isPaused = false
} else {
timer.invalidate()
isPaused = true
}
}
To Start:
timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: Selector("updateView"), userInfo: nil, repeats: true)
To Resume:
timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: Selector("updateView"), userInfo: nil, repeats: true)
To Pause:
timer.invalidate
This worked for me. The trick is that do not look for something like "timer.resume" or "timer.validate". Just use "the same code for starting a timer" to resume it after the pause.
To start
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(ViewController.action), userInfo: nil, repeats: true)
To pause
timer.invalidate()
To reset
time += 1
label.text = String(time)
'label' is the timer on output.
I was just working through a similar problem with my game, and found an easy solution.
First I should point out like others have, that Timer and NSTimer doesn't have a pause function. You have to stop the Timer with Timer.invalidate(). After invalidating a Timer, you must initialize it again to start the Timer. To quote from https://developer.apple.com/documentation/foundation/timer, the function .invalidate() -
Stops the timer from ever firing again and requests its removal from
its run loop.
To pause a timer we can use Timer.fireDate, this is where Timer (and NSTimer) saves the date for when the Timer will fire in the future.
Here's how we can pause a Timer by saving the seconds left that the Timer has until it fires again.
//The variable we will store the remaining timers time in
var timeUntilFire = TimeInterval()
//The timer to pause
var gameTimer = Timer.scheduledTimer(timeInterval: delaysShow!, target: self, selector: #selector(GameClass.showRocket), userInfo: rocketid[i], repeats: false)
func pauseTimer()
{
//Get the difference in seconds between now and the future fire date
timeUntilFire = gameTimer.fireDate.timeIntervalSinceNow
//Stop the timer
gameTimer.invalidate()
}
func resumeTimer()
{
//Start the timer again with the previously invalidated timers time left with timeUntilFire
gameTimer = Timer.scheduledTimer(timeInterval: timeUntilFire, target: self, selector: #selector(GameClass.showRocket), userInfo: rocketid[i], repeats: false)
}
Note: Don't invalidate() the Timer before getting the fireDate. After invalidate() is called the Timer seems to reset the fireDate to 2001-01-01 00:00:00 +0000.
2nd Note: A timer can potentially fire after its set fireDate. This will lead to a negative number, which will default the Timer to run after 0.1 milliseconds instead. https://developer.apple.com/documentation/foundation/timer/1412416-scheduledtimer
To stop it
time3.invalidate()
To start it again
time3.fire()
You can not resume the timer back.
Instead of resuming - just create a new timer.
class SomeClass : NSObject { // class must be NSObject, if there is no "NSObject" you'll get the error at runtime
var timer = NSTimer()
init() {
super.init()
startOrResumeTimer()
}
func timerAction() {
NSLog("timer action")
}
func pauseTimer() {
timer.invalidate
}
func startOrResumeTimer() {
timer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: Selector("timerAction"), userInfo: nil, repeats: true)
}
}
Even though the solutions exposed here are good, I thought an important insight was missing. Like a lot of people here explained, timer invalidate() and recreate is the best option. But one could argue that you could do something like this:
var paused:Bool
func timerAction() {
if !paused {
// Do stuff here
}
}
is easier to implement, but it will be less efficient.
For energy impact reasons, Apple promotes avoiding timers whenever possible and to prefer event notifications. If you really need to use a timer, you should implement pauses efficiently by invalidating the current timer. Read recommendations about Timer in the Apple Energy Efficiency Guide here:
https://developer.apple.com/library/content/documentation/Performance/Conceptual/EnergyGuide-iOS/MinimizeTimerUse.html
SWIFT3
Global Declaration :
var swiftTimer = Timer()
var count = 30
var timer = Timer()
#IBOutlet weak var CountDownTimer: UILabel!
viewDidLoad
override func viewDidLoad() {
super.viewDidLoad()
BtnStart.tag = 0
}
Triggered IBACTION :
#IBAction func BtnStartTapped(_ sender: Any) {
if BtnStart.tag == 0 {
BtnStart.setTitle("STOP", for: .normal)
timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(ScoreBoardVC.update), userInfo: nil, repeats: true)
BtnStart.tag = 1
} else {
BtnStart.setTitle("START", for: .normal)
timer.invalidate()
BtnStart.tag = 0
}
}
Function that Handles The things :
func update(){
if(count > 0){
let minutes = String(count / 60)
let ConvMin = Float(minutes)
let minuttes1 = String(format: "%.0f", ConvMin!)
print(minutes)
let seconds = String(count % 60)
let ConvSec = Float(seconds)
let seconds1 = String(format: "%.0f", ConvSec!)
CountDownTimer.text = (minuttes1 + ":" + seconds1)
count += 1
}
}
Pause timer : timer.invalidate()
and
Resume timer : recreate timer. it's work fine.
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(mainController.updateTimer), userInfo: nil, repeats: true)