The timer starts and countdowns while updating the title of the button when the view is loaded. I've called startTimer in viewDidLoad. This works fine as expected.
However, the problem I faced is when I call startTimer from the IBAction. I've verified the timer is working and the selector is being called. The button title doesn't change tho. What could be wrong in this case?
class ViewController: UIViewController {
#IBOutlet weak var button: UIButton?
var timer: Timer?
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
startTimer()
}
func startTimer() {
countdownSeconds = 60
timer?.invalidate()
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: true)
}
#objc func updateTimer() {
countdownSeconds -= 1
let countdown = countdownFormatter.string(from: TimeInterval(countdownSeconds))!
if countdownSeconds > 0 {
UIView.performWithoutAnimation {
button?.setTitle(countdown, for: .normal)
}
} else {
timer?.invalidate()
}
}
#IBAction func buttonTapped(_ sender: UIButton) {
startTimer()
}
}
While coming to a view I call a function to load a timer like so...
var count = 10
func startTimer() {
timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(self.update), userInfo: nil, repeats: true)
}
and update function is given as..
#objc func update() {
while (count != 0) {
count -= 1
countdownLabel.text = "\(count)"
}
timer.invalidate()
}
But what happens is when I come to this view, straightaway the number 0 is shown as opposed to ideally displaying all numbers in the sequence 9,8,7,6,5,4,3,2,1,0
What am I doing wrong here..?
Swift 4:
var totalTime = 10
var countdownTimer: Timer!
#IBOutlet weak var timeLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
startTimer()
}
This method call initializes the timer. It specifies the timeInterval (how often the a method will be called) and the selector (the method being called).
The interval is measured seconds so for it to perform like a standard clock we should set this argument to 1.
func startTimer() {
countdownTimer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(updateTime), userInfo: nil, repeats: true)
}
// Stops the timer from ever firing again and requests its removal from its run loop.
func endTimer() {
countdownTimer.invalidate()
}
//updateTimer is the name of the method that will be called at each second. This method will update the label
#objc func updateTime() {
timeLabel.text = "\(totalTime)"
if totalTime != 0 {
totalTime -= 1
} else {
endTimer()
}
}
I want to know how it is possible to grab the time from a UIDatePicker in Count Down Timer mode, and then display that while counting down in a Hour:Minute:Second format. My biggest issue is actually grabbing the time from the Date Picker. As I'm not really to sure how to start that.
override func viewDidLoad() {
super.viewDidLoad()
stopWatchPicker.countDownDuration = 60.0;
if timerCount == 0 {
timerRunning = false
}
}
var timerCount = 60 //set to 60 for testing purposes
var timer = Timer()
var timerRunning = false
#IBOutlet weak var stopWatchPicker: UIDatePicker!
#IBOutlet weak var countDownLabel: UILabel!
#IBAction func startButton(_ sender: AnyObject) {
if timerRunning == false {
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
timerRunning = true
}
}
#IBAction func stopButton(_ sender: AnyObject) {
timer.invalidate()
timerRunning = false
}
func updateCounter() {
timerCount -= 1
countDownLabel.text = "\(timerCount)"
if timerCount == 0 {
timer.invalidate()
timerRunning = false
}
}
You need to grab the countDownDuration from the stopWatchPicker and assign it to the timerCount variable.
#IBAction func startButton(_ sender: AnyObject) {
if timerRunning == false {
timerCount = stopWatchPicker.countDownDuration
timerRunning = true
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
}
}
Cheers!
I'm trying to push the next view controller after a delay, using a timer.
I already made an app with an one second timer, but I'd like it to stop after a period of time.
import UIKit
class Level1: UIViewController {
var timerCount = 0
var timmerRunning = false
var timer = NSTimer()
#IBOutlet weak var timerLabel: UILabel!
func Counting() {
timerCount += 1
timerLabel.text = "\(timerCount)"
}
#IBAction func startButton(sender: UIButton) {
if !timmerRunning {
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("Counting"), userInfo: nil, repeats: true)
timmerRunning = true
}
}
#IBAction func stopButton(sender: UIButton) {
if timmerRunning {
timer.invalidate()
timmerRunning = false
}
}
#IBAction func restartButton(sender: UIButton) {
timerCount = 0
timerLabel.text = "0"
}
}
You can check your timerCount variable in the counting function like that and after it has reached your desired period of time, stop the timer and present the new ViewController:
func Counting() {
timerCount += 1
timerLabel.text = "\(timerCount)"
if timerCount == desiredPeriodOfTime {
self.timer.invalidate()
self.timmerRunning = false
dispatch_async(dispatch_get_main_queue()){
let viewController = NewViewController()
self.presentViewController(viewControllerToPresent: viewController, animated: true, completion: nil)
}
}
}
I want to add a score to the top of my scene in the game I am working on. The score is going to based on how long you last, and will increase every second. Thanks for the help in advance!
import SpriteKit
class easyScene: SKScene {
let scrollBarEasyBottom = SKSpriteNode(imageNamed: "scrollBarEasyBottom")
let scrollBarEasyTop = SKSpriteNode(imageNamed: "scrollBarEasyTop")
let ball = SKSpriteNode(imageNamed: "ball")
var origSBEBpositionX = CGFloat(0)
var origSBETpositionX = CGFloat(0)
var maxSBEBX = CGFloat(0)
var SBEBSpeed = 5
var maxSBETX = CGFloat(0)
var SBETSpeed = 5
var score = 0
var timer: NSTimer?
var scoreText = SKLabelNode(fontNamed: "Kailasa")
override func didMoveToView(view: SKView) {
println("Easy Scene is the location")
self.backgroundColor = UIColor.blackColor()
self.scrollBarEasyBottom.position = CGPoint(x:0, y:270)
self.addChild(self.scrollBarEasyBottom)
self.scrollBarEasyBottom.yScale = 0.2
self.origSBEBpositionX = self.scrollBarEasyBottom.position.x
// end scrollBarEasyBottom
self.scrollBarEasyTop.position = CGPoint(x:20, y:400)
self.addChild(self.scrollBarEasyTop)
self.scrollBarEasyTop.yScale = 0.2
self.origSBETpositionX = self.scrollBarEasyTop.position.x
// end scrollBarEasyTop
self.ball.position = CGPoint(x:40, y:293)
self.addChild(self.ball)
self.ball.yScale = 0.17
self.ball.xScale = 0.17
// end ball
self.maxSBEBX = self.scrollBarEasyBottom.size.width - self.frame.size.width
self.maxSBEBX *= -1
self.maxSBETX = self.scrollBarEasyTop.size.width - self.frame.size.width
self.maxSBETX *= -1
//
self.scoreText.text = "0"
self.scoreText.fontSize = 60
self.scoreText.position = CGPoint(x: CGRectGetMidX(self.frame), y: 500)
self.scoreText.text = String(self.score)
self.addChild(self.scoreText)
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("scoreIncrease") , userInfo: nil, repeats: true)
func scoreIncrease (){
score++
println(score)
}
}
override func update(currentTime: NSTimeInterval) {
if self.scrollBarEasyBottom.position.x <= maxSBEBX + 1200 {
self.scrollBarEasyBottom.position.x = self.origSBEBpositionX
}
if self.scrollBarEasyTop.position.x <= maxSBETX + 1200 {
self.scrollBarEasyTop.position.x = self.origSBETpositionX
}
scrollBarEasyBottom.position.x -= CGFloat(self.SBEBSpeed)
scrollBarEasyTop.position.x -= CGFloat(self.SBETSpeed)
// moving bars
var degreeRotation = CDouble(self.SBEBSpeed) * M_PI / 180
self.ball.zRotation -= CGFloat(degreeRotation)
//rotate ball
}
}
After running this code, I always get an
unrecognized selector sent to instance error
You can use one like this:
var timer = NSTimer()
override func viewDidLoad() {
scheduledTimerWithTimeInterval()
}
func scheduledTimerWithTimeInterval(){
// Scheduling timer to Call the function "updateCounting" with the interval of 1 seconds
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateCounting"), userInfo: nil, repeats: true)
}
func updateCounting(){
NSLog("counting..")
}
Swift 3:
var timer = Timer()
override func viewDidLoad() { // Use for the app's interface
scheduledTimerWithTimeInterval()
}
override func didMove(to view: SKView) { // As part of a game
scheduledTimerWithTimeInterval()
}
func scheduledTimerWithTimeInterval(){
// Scheduling timer to Call the function "updateCounting" with the interval of 1 seconds
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(self.updateCounting), userInfo: nil, repeats: true)
}
#objc func updateCounting(){
NSLog("counting..")
}
Swift 5:
Note: this solution is compatible with iOS 10.0+.
// If needing to check for iOS compatibility use
// if #available(iOS 10.0, *) {code}
var timer = Timer()
override func viewDidLoad() {
self.timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true, block: { _ in
updateCounting()
})
}
func updateCounting(){
print("counting...")
}
You can then invalidate (stop) the timer using:
timer.invalidate()
There is something called NSTimer in swift which could solve your problem. I have given an example like how you can use it. Just customise it for your purpose.
var timer = NSTimer.scheduledTimerWithTimeInterval(1.0,
target: self,
selector: Selector("yourMethodToCall"),
userInfo: nil,
repeats: true)
Add this line to the place where you need to call your function repeatedly.
The 1.0 refers to 1 second.
Change the selector to call yourMethodName
repeats is set to true to call that function every second.
Try this out and let me know if your are stuck somewhere. Thanks.
Swift 3
find this solution it worked for me
weak var timer: Timer?
var timerDispatchSourceTimer : DispatchSourceTimer?
func startTimer() {
if #available(iOS 10.0, *) {
timer = Timer.scheduledTimer(withTimeInterval: 3, repeats: true) { [weak self] _ in
// do something here
}
} else {
// Fallback on earlier versions
timerDispatchSourceTimer = DispatchSource.makeTimerSource(flags: [], queue: DispatchQueue.main)
timerDispatchSourceTimer?.scheduleRepeating(deadline: .now(), interval: .seconds(60))
timerDispatchSourceTimer?.setEventHandler{
// do something here
}
timerDispatchSourceTimer?.resume()
}
}
func stopTimer() {
timer?.invalidate()
//timerDispatchSourceTimer?.suspend() // if you want to suspend timer
timerDispatchSourceTimer?.cancel()
}
// if appropriate, make sure to stop your timer in `deinit`
deinit {
stopTimer()
}
I prefer
var timer: Timer?
override func viewDidLoad() {
super.viewDidLoad()
timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { (timer) in
// Do what you need to do repeatedly
}
}
To stop it:
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if timer != nil {
timer?.invalidate()
timer = nil
}
}
Xcode 10.2 Swift 5:
override func viewDidLoad() {
super.viewDidLoad()
// ...
Timer.scheduledTimer(timeInterval: 8.0, target: self, selector: Selector(("your #obcj func name")), userInfo: nil, repeats: true)
}
//Anywhere in the same view controller to stop the loop:
Timer.cancelPreviousPerformRequests(withTarget: your #obcj func name())
I don't think you need NSTimer for this.
Since you are using SpriteKit, I am going to suggest simplest solution in my opinion:
Declare a variable var prevScoreCalcTime:TimeInterval = 0
Inside of update func in your GameScene set it up like below:
override func update(_ currentTime: TimeInterval) {
if currentTime - prevScoreCalcTime > 1 {
prevScoreCalcTime = currentTime
// Any function you put here will execute every second
}
}
Good luck!
// For running a piece of code every second
///Runs every second, to cancel use: timer.invalidate()
#discardableResult public static func runThisEvery(
seconds: TimeInterval,
startAfterSeconds: TimeInterval,
handler: #escaping (CFRunLoopTimer?) -> Void) -> Timer {
let fireDate = startAfterSeconds + CFAbsoluteTimeGetCurrent()
let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, fireDate, seconds, 0, 0, handler)
CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, CFRunLoopMode.commonModes)
return timer!
}