Overview: I am trying to create quiz game where someone has to answer questions in a certain amount of time. They have 10 seconds to solve each question or it will move to the next controller. The problem is that whenever I click next question before the full time is up it keeps counting down to 10. What should happen is it should stop counting time for that question.
So far I have implemented the following code to try to make this work. var time = 0 and first created a global variable called time. Then I created timer code as following, var count = 10 #IBOutlet var countDownLabel: UILabel!
Then I create a label that will tick down every second until it reaches 0. Code as follows:
if(count > 0) {
countDownLabel.text = String(count)
count -= 1
time += 1
}
print (time)
if (count <= 0 ) {
count = 10
self.performSegue(withIdentifier:"NextQuestion1", sender: nil)
}
Summary: Everytime count goes down time should go up. Then at the end it will display the time they. I would gladly appreciate some help on this problem.
When you click on the next button, you need to invalidate the timer so that it will stop counting.
Say you created your timer in this way
let timer = Timer.scheduledTimer(timeInterval: 10, target: self, selector: #selector(YourSegueFunction), userInfo: nil, repeats: false)
Then when you click on the next button, use the following line of code to stop the timer
timer.invalidate()
Here is the demo
Related
I want to add a button with one purpose, when the user click, it'll add one more product to the chart.
The thing in my mind is, I'll create a counter, if the user click faster than 0.5 seconds, counter will increase, but the value will not go to the server. When users last click is more than 1 second ago, last value of the counter will go to the server as the order amount. My goal is, if user will add, for example 10 amount of same order very fast, I don't want to send all clicks one by one to the server, instead send all clicks sum (which is the counter value) at once when 1 second passed after last user click.
I saw people says it can be done with NSOperations. But I couldn't figure out how.
var counter = 0
#IBAction func addProductAmount (_ sender: Any) {
// 1. Increase counter
// 2. If only 0.5 seconds or less time passed, don't send the counter value, wait it to be 1 seconds
// 3. Send counter value 1 seconds after last user click
}
Code will be something like this. But how can use Operation Queue for this? Any help?
I'm learning swift and I don't know Objective-C at all.
The thing you want to do is called throttling. So you can use this code:
var counter = 0
timer: Timer?
#IBAction func addProductAmount (_ sender: Any) {
counter += 1
timer?.invalidate()
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(sendRequest), userInfo: nil, repeats: false)
}
func sendRequest() {
// your method to make a request to the server
}
This question already has an answer here:
Show Multiple Counter in label but at same screen (Swift, IOS)
(1 answer)
Closed 5 months ago.
In my app I have spots on which a user can tap to unlock them, a user can unlock multiple spots at the same time and there can be different number of spots every time, whenever a user unlocks a spot i want to show a timer of 60 seconds on the unlocked spot, So, there can be multiple timers on same screen all having different counts. For example if a user unlocks 2 spots with the difference of 30 seconds. the timer on spot 1 should be 30 seconds left and spot 2 should be 60 seconds left. I only have 1 function for doing this task I can easily show timer on 1 spot but showing them on multiple places, multiple times is very complex. I am sharing a picture too for reference. any help would be appreciated.
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
#objc func updateCounter() {
if counter > 0 {
let time = Int(counter/60)
let dec = Int(counter.truncatingRemainder(dividingBy: 60))
spotTiming = String(time) + ":" + String(dec)
}
counter -= 1
}
i want to show timers where counter is written
You can use a timer as a trigger to update the UI every x period (example: 0.5s). You save time remaining every spots at a variable as Array and reduce each element when timer was triggered.
let step = TimeInterval(0.5)
timer = Timer.scheduledTimer(timeInterval: step, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
var timer_remainings = [TimeInterval]()
#objc func updateCounter() {
for (index, item) in timer_remainings.enumerated() {
timer_remainings[index] = max(0.0, timer_remainings - step)
}
// Update UI
updateUI()
}
[New to Swift]
I am making an app on Swift 5 that displays time left before my next task is to start.
My app:
Task 1: Start at 9.30 am
Task 2: Start at 10.15 am
Let's say Current Time: 09.00 am
Countdown: Time before next task start = 00:30:02 --> 00:30:01 ...
I would like to display countdown of the nearest task.
Currently, I can only have one countdown timer on my viewonLoad() that picks up the current countdown. It continues and once it finishes it does not start next timer after it has finished. I understand I have to deal with Background state at a later date, but since I am slowly starting. My idea is to make sure I can initiate next countdown timer once my current one has expired.
So at any point when I open my app, it will always display countdown till my next task.
var count = 30 // calculation simplified ... this data is calc from two different date obj
override func viewDidLoad() {
super.viewDidLoad()
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(update), userInfo: nil, repeats: true)
}
#objc func update() {
if(count > 0) {
count = count - 1
countdownLabel.text = String(count)
}else{
timer!.invalidate()
getNextTaskTimes()
}
}
func getNextTaskTimes(){
count = 5 // not working
}
How can I achieve this please? Also, is there a better way of doing this? Given that, my user may choose to close the app and come back at a later time, I still would want my countdown to continue in the background.
Any help is appreciated. :D Thanks
I realized the above code works. I just need to make sure I do not invalidate the timer in the else block. Invalidating the timer just kills it.
I am making an app where the user can have multiple timers going at once and see them in a list view.
I am aware that there are 2 main options for working out time:
Subtract the date started from current date (current date-start date)
OR
Use an NSTimer and take away 1 second every second from each active timer.
I have previously been using the latter, but having looked around the internet I am starting to think that the data one may be better.
Please could you let me know which you think is best to use, and if you chose the first one (dates), please could you provide some sample code on how to use it.
You can Use an NSTimer and take away 1 second every second from each active timer. You can use this class.
class CustomTimer {
typealias Update = (Int)->Void
var timer:Timer?
var count: Int = 0
var update: Update?
init(update:#escaping Update){
self.update = update
}
func start(){
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(timerUpdate), userInfo: nil, repeats: true)
}
func stop(){
if let timer = timer {
timer.invalidate()
}
}
/**
* This method must be in the public or scope
*/
#objc func timerUpdate() {
count += 1;
if let update = update {
update(count)
}
}
}
To use multiple timer you can create multiple instance of CustomTimer, Example Code:
let timer1 = CustomTimer { (seconds) in
// do whatever you want
}
timer1.start()
let timer2 = CustomTimer { (seconds) in
// do whatever you want
}
timer2.start()
NOTE:
timerUpdate method will be called exactly at 1 second interval. to keep some space for function execution we can set interval to 0.9 or 0.95 according to time taken by execution.
You use both. You have one Timer that repeats every second. The handler for the Timer then iterates through your list of start dates for each of the user's timers and you update the display for each based on the current date.
Newbie to IOS programming - learning through Swift. I'm writing a simple "slot machine / dice game".
I'm trying to show the user a flashing sequence of rolls before the "actual" roll appears.
func doFancyDiceRoll() {
for x in 1...100 {
Die1.image = PipsImg[RollOne()]
Die2.image = PipsImg[RollOne()]
Die3.image = PipsImg[RollOne()]
}
}
Die1, etc., are defined as generic UIImage views.
In any case, I'm not seeing the 100x iterations, just the images at the end of the loop. I'm assuming that either it redraws "too fast" or that IOS is trying to be smart, and only draws the last images so as to conserve resources.
I'll wildly guess that I need to either implement some kind of delay here, or, IOS needs to be told to explicitly draw out my images, and not try to outthink my intent.
For the delay, I've seen something about NSTimer, but nothing I saw seems to simply say something like "pause for .05" second, and the whole construct was unclear as they were ObjC examples/conversions.
(Note: I've simplified things here --- normally, I would store the value of RollOne() so I can use it later. I also would like to make an array (or collection?) like Die[1].image, but that is another question.)
========== Edit =======
OK, so I'm following up with more of my original code, merged in with that of #doctordoder so we can discuss a bit better. Hopefully that is kosher. (If this appended question is too long, please advise me on the best way to post a lengthy follow-up directly.)
import UIKit
class ViewController: UIViewController {
//( stripping out stuff unneeded for discussion )
// refers to same label below - works but kosher??
#IBOutlet var btnRoll_x: UIView
#IBAction func btnRoll(sender: AnyObject) {
triggerRoll()
}
var timer : NSTimer? = nil
var rolls : Int = 0
func triggerRoll() {
//hiding is bad UI, but until i know how to "disable & dim"
btnRoll_x.hidden = true
timer = NSTimer.scheduledTimerWithTimeInterval(0.10, target: self, selector: "doFancyDiceRoll", userInfo: nil, repeats: true);
}
func doFancyDiceRoll() {
Die1.image = PipsImg[randomInt(6)]
Die2.image = PipsImg[randomInt(6)]
Die3.image = PipsImg[randomInt(6)]
if (++rolls > 10)
{
timer?.invalidate()
timer = nil
rolls = 0 // DCB added this presumed missing line
btnRoll_x.hidden = false //again, need to do this better
}
}
}
Hopefully, my implementation of the code is what would have been intended. I made some minor adjustments for (hopeful) clarity.
Good news is I have working code. I have just enough understanding to get in place, but I'm fuzzy on some details.
Here is what I (think I) know...
We declare an NSTImer object, and a roll counter at the main level of the class. I note that in my original version, I had the roll counter scoped within the rolling function itself. Took me a while to understand why it could not live in the DiceRoll loop itself, but now I do. I'm going to express it poorly, but since the timer is going to call DiceRoll multiple instances, it needs to live outside the function.
The button btnRoll gets touched, and invokes triggerRoll().
To prevent the user from touching the button while we are in progress, which put us into a state where the roll counter never got to zero, I hide the button. (I'll figure how to properly put in in disabled state later.)
The timer is set. It fires every .1 second (within limits), and is set to repeat. (until .invalidate ). And it "calls" the function doFancyDiceRoll via the selector: attribute.
So, the big change as previously noted is that doFancy..Roll() no longer loops. It excites a single instance up updating the images. It checks the counter, and if we reach the limit, we kill the timer, which stops the timer (invalidate). (And I unhide the button, making it available again.)
So, a few things I am concerned/wondering about: I get the value of timers for other things that need to happen periodically (take health away every second, check a GPS position every 10 seconds, etc.). It's seems a odd construct to force a screen refresh.
Frankly, I would have expected to see see something like this:
func doFancyDiceRoll() {
for x in 1...100 {
Die1.image = PipsImg[RollOne()] // and 2 and 3 of course.....
VIewController.forceRedraw <<=== something like this, or maybe
ViewController.wait(.05) <<== this?? I dunno ;-)
}
}
instead we end up with about 20 extra lines or so. I'd be interested in knowing if there other approaches that could work keeping the loop intact.
Anyway, assuming this is the one true way to go, I guess my followup to this is how do I pass parameters, since this is not a "real" function call. Trying
selector: "doFancyDiceRoll(40)"
was not objected to by the IDE, but failed in execution.
I had exactly same problem back in days, entire loop is finished before the view is refreshed as #doctordoder mentioned. Solved with using NSTimer
var rollCount = 0
let arrayOfImages = ["image01", "image02", "image03"]
var timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: Selector("doFancyDiceRoll"), userInfo: nil, repeats: true)
func doFancyDiceRoll() {
if rollCount == 100 {
timer.invalidate
rollCount = 0
{
else {
//get images from array arrayOfImages[rollCount]
rollCount++
}
}
there could be typos, since I have no Xcode right now.
I have basically the same answer as above :(, but I thought I'd post it anyway.
var timer : NSTimer? = nil
var rolls : Int = 0
func doFancyDiceRoll() {
timer = NSTimer.scheduledTimerWithTimeInterval(0.10, target: self, selector: "roll", userInfo: nil, repeats: true);
}
func roll() {
println("rolling")
Die1.image = PipsImg[RollOne()]
Die2.image = PipsImg[RollOne()]
Die3.image = PipsImg[RollOne()]
if (++rolls > 100)
{
timer?.invalidate()
timer = nil
}
}
Rather than NSTimer and invalidating, you can use dispatch_after to do the work for you.
func rollDice(howManyTimes: Int) {
die1.image = PipsImg[RollOne()]
die2.image = PipsImg[RollOne()]
die3.image = PipsImg[RollOne()]
if howManyTimes > 0 {
let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(Double(NSEC_PER_SEC) / 10.0))
dispatch_after(delayTime, dispatch_get_main_queue()) {
self.rollDice(howManyTimes - 1)
}
}
}
This will run the code for the number of times specified, delaying each time by 0.1 seconds. It works like this: First it sets the images on each die, then, if there are more iterations, it does a dispatch_after to call itself with rollDice(howManyTimes - 1)
With this, you don't need to maintain a NSTimer and it is pretty self contained.