Problem is to stop NSTimer, for some reason [Timer invalidate] just not working...
Maybe my eyes are full of soap, but can't understand the reason why the timer didn't stop at 0, but go reverse counting -1, -2, -3 and so on...(((
I'm using epoch numbers as destination date. One more thing - my button "IBAction stop" with [Timer invalidate] works just fine - when i push it in simulator timer stops...
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
Timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(updateLabel) userInfo:nil repeats:YES];
}
- (IBAction) start {
Timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(updateLabel) userInfo:nil repeats:YES];
}
- (IBAction) stop {
[Timer invalidate];
Timer = nil;
}
-(void)updateLabel {
NSCalendar *calender = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
int units = NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
NSDateComponents *components = [calender components:units fromDate:[NSDate date] toDate:destinationDate options:0];
[dateLabel setText:[NSString stringWithFormat:#"%d%c %d%c %d%c %d%c", [components day], 'd', [components hour], 'h', [components minute], 'm', [components second], 's']];
destinationDate = [NSDate dateWithTimeIntervalSince1970:1355299710];
if (!destinationDate) {
[Timer invalidate];
Timer = nil;
}
}
As Totumus pointed out, your if statement condition !destinationDate always evaluates to false, so your updateLabel method never invalidates your timer.
You have another bug too:
You're creating a timer in viewDidLoad and storing a reference to it in your Timer instance variable.
Then you're creating another timer in start and storing a reference to it in your Timer instance variable, overwriting the reference to the timer you created in viewDidLoad without invalidating that older timer.
So now you have two timers running, but you don't have a reference to the older timer, so you can never invalidate it.
Note that the run loop has a strong reference to a scheduled (running) timer, so even if you remove all of your strong references to it, the timer keeps running. That's why the invalidate message exists: to tell the run loop to remove its strong reference to the timer.
Related
There are several recipes in my CoreData. Every recipe has attributes prepHour and prepMin. I would like by tapping to button Start Timer start countdown timer. But there can be several timers (for example for each recipe) which must work simultaneously
I selected this way (may be it's wrong):
For timers I used singleton Timers.
By tapping to my Start Timer I call method with parameters (name, prepHour, prepMin)
My startTimer method creates timer and puts it to NSMutableDictionary
Calling method:
[[Timers sharedTimers] startTimer:self.recipe.name startTimer:self.recipe.prepHour startTimer:self.recipe.prepMin];
In Timers singleton:
- (void)startTimer:(NSString *)timerName startTimer:(NSNumber *)hVal startTimer:(NSNumber *)mVal
{
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:60.0f target:self selector:#selector(tick:) userInfo:nil repeats:YES];
if ([timer isValid]) {
NSArray *array = [NSArray arrayWithObjects: timer, hVal, mVal, nil];
if (_timerDict == NULL) {
_timerDict = [[NSMutableDictionary alloc] init];
}
[_timerDict setObject:array forKey:timerName];
NSLog(#"%#", _timerDict);
}
}
- (void)stopTimer:(NSString *)timerName
{
NSArray *array = [_timerDict objectForKey:timerName];
NSTimer *timer = [array objectAtIndex:0];
if ([timer isValid]) {
[timer invalidate];
[_timerDict removeObjectForKey:timerName];
}
}
- (void)tick:(NSString *)timerName
{
NSArray *array = [_timerDict objectForKey:timerName];
//NSTimer *timer = [array objectAtIndex:0];
NSInteger hVal = [[array objectAtIndex:1] integerValue];
NSInteger mVal = [[array objectAtIndex:2] integerValue];
NSInteger sVal = 0;
How should I use tick method for each timer? I would like each timer call this method with own parameters (timer, prepHour, prepMin)
This may be a matter of taste, but I don't use timers to remember an expiration time, I use them to pulse at a frequency. For your app, I'd use one timer at the lowest common denominator frequency, like one second. Instead of a singleton, I have a single timer, that the app delegate can invalidate and restart.
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:#selector(tick:) userInfo:nil repeats:YES];
Then keep each expiration as one property on each recipe. For example:
- (IBAction)pressedStartButtonForRecipeA:(id)sender {
// this is a NSDate * property
self.recipeADone = [NSDate dateWithTimeIntervalSinceNow:90*60]; // ninety minutes
}
- (void)tick:(NSTimer *)timer {
NSDate *now = [NSDate date];
NSTimeInterval secondsUntilAIsDone = [self.recipeADone timeIntervalSinceDate:now];
if (secondsUntilAIsDone <= 0.0) {
// update UI to say that A is done
} else {
// update UI to reduce countdown
}
// and so on for all recipes
}
This sounds like a poor use of a singleton. I would have…well, one timer per timer if you want to go with this design. Alternatively, you could have one timer and just calculate the offset from each timer's start when it ticks. (Which approach makes sense depends on your particular app. I'd usually go with the second, but YMMV.)
Also, timers do not pass an NSString to their callback; they pass themselves. To allow the callback to get some information from the timer, you can set the info its the timer's userInfo dictionary.
I just went through trying to make an alarm clock app with local notifications but that didn't do the trick because I needed an alert to appear instead of it going into notification centre in iOS 5+
So far I've been struggling greatly with nstimer and its functions so I was wondering if anyone could help out.
I want when the user selects a time (through UIDatePicker, only time) for an alert to be displayed at exactly this time. I have figured out how to get the time from UIDatePicker but I do not know how to properly set the firing function of nstimer. This is what I have attempted so far, if anyone could help... be much appreciated. Thank you
Example (it keeps going into the function every second opposed to a certain time I told it too... not what I want):
NSDate *timestamp;
NSDateComponents *comps = [[[NSDateComponents alloc] init] autorelease];
[comps setHour:2];
[comps setMinute:8];
timestamp = [[NSCalendar currentCalendar] dateFromComponents:comps];
NSTimer *f = [[NSTimer alloc] initWithFireDate:timestamp
interval:0
target:self
selector:#selector(test)
userInfo:nil repeats:YES];
NSRunLoop *runner = [NSRunLoop currentRunLoop];
[runner addTimer:f forMode: NSDefaultRunLoopMode];
As #Nate said change
NSTimer *f = [[NSTimer alloc] initWithFireDate:timestamp
interval:0
target:self
selector:#selector(test)
userInfo:nil repeats:YES];
To
NSTimer *f = [[NSTimer alloc] initWithFireDate:timestamp
interval:0
target:self
selector:#selector(test)
userInfo:nil repeats:NO]; //<-- Change here
This is my code for an iPhone stopwatch. It works as expected and stops and resumes when the buttons are clicked.
When I hit "Stop", however, the timer won't stop running in the background, and when I hit "Start" to resume it, it will update the time and skip to where it is currently instead of resuming from the stopped time.
How can I stop the NSTimer? What is causing this to occur?
#implementation FirstViewController;
#synthesize stopWatchLabel;
NSDate *startDate;
NSTimer *stopWatchTimer;
int touchCount;
-(void)showActivity {
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"mm:ss.SS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
NSString *timeString=[dateFormatter stringFromDate:timerDate];
stopWatchLabel.text = timeString;
[dateFormatter release];
}
- (IBAction)onStartPressed:(id)sender {
stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1/10 target:self selector:#selector(showActivity) userInfo:nil repeats:YES];
touchCount += 1;
if (touchCount > 1)
{
[stopWatchTimer fire];
}
else
{
startDate = [[NSDate date]retain];
[stopWatchTimer fire];
}
}
- (IBAction)onStopPressed:(id)sender {
[stopWatchTimer invalidate];
stopWatchTimer = nil;
[self showActivity];
}
- (IBAction)reset:(id)sender; {
touchCount = 0;
stopWatchLabel.text = #"00:00.00";
}
Your calculation of the current display always uses the original start time of the timer, so the display after pausing includes the interval that the timer was paused.
The easiest thing to do would be to store another NSTimeInterval, say secondsAlreadyRun, when the timer is paused, and add that to the time interval you calculate when you resume. You'll want to update the timer's startDate every time the timer starts counting. In reset:, you would also clear out that secondsAlreadyRun interval.
-(void)showActivity:(NSTimer *)tim {
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
// Add the saved interval
timeInterval += secondsAlreadyRun;
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"mm:ss.SS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
NSString *timeString=[dateFormatter stringFromDate:timerDate];
stopWatchLabel.text = timeString;
[dateFormatter release];
}
- (IBAction)onStartPressed:(id)sender {
stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1/10
target:self
selector:#selector(showActivity:)
userInfo:nil
repeats:YES];
// Save the new start date every time
startDate = [[NSDate alloc] init]; // equivalent to [[NSDate date] retain];
[stopWatchTimer fire];
}
- (IBAction)onStopPressed:(id)sender {
// _Increment_ secondsAlreadyRun to allow for multiple pauses and restarts
secondsAlreadyRun += [[NSDate date] timeIntervalSinceDate:startDate];
[stopWatchTimer invalidate];
stopWatchTimer = nil;
[startDate release];
[self showActivity];
}
- (IBAction)reset:(id)sender; {
secondsAlreadyRun = 0;
stopWatchLabel.text = #"00:00.00";
}
Don't forget to release that startDate somewhere appropriate! Also keep in mind that the documented NSTimer interface is for the method you give it to accept one argument, which will be the timer itself. It seems to work without that, but why tempt fate?
Finally, since you're using that NSDateFormatter so much, you might want to consider making it an ivar or put it in static storage in showActivity:, like so:
static NSDateFormatter * dateFormatter = nil;
if( !dateFormatter ){
dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"mm:ss.SS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
}
So, when the user presses stop, and then start again, you aren't resetting the start time. But when you update the label, you are basing that on the total elapsed time from the original start time to the current time.
So if you run the timer for 10 seconds, stop, wait 10 seconds, and then start again, the timer will show 00:20.00 and start counting again from there.
What you want to do is reset the start time each time the user starts the clock, but then add the elapsed times of all previous runs as well. Or something similar.
BTW, you are leaking the start time every time you reset it now. Minor bug.
EDIT: looks like #Josh Caswell was thinking the same thing, but he types a LOT faster. :)
Are you using ARC or not?
If you are using ARC, it looks like you arent using a _strong reference. If you aren't using ARC, it doesn't looking you are retaining a reference to the timer.
I'm posting this from mobile so might be missing something.
EDIT: just noticed you were using release elsewhere, so I'll assume no ARC. You need to retain the timer after setting it to be able to access it later and invalidate.
You can use NSTimeInterval instead of timer. I have a functional code to pause and stop the timer.
#interface PerformBenchmarksViewController () {
int currMinute;
int currSecond;
int currHour;
int mins;
NSDate *startDate;
NSTimeInterval secondsAlreadyRun;
}
#end
- (void)viewDidLoad
{
[super viewDidLoad];
running = false;
}
- (IBAction)StartTimer:(id)sender {
if(running == false) {
//start timer
running = true;
startDate = [[NSDate alloc] init];
startTime = [NSDate timeIntervalSinceReferenceDate];
[sender setTitle:#"Pause" forState:UIControlStateNormal];
[self updateTime];
}
else {
//pause timer
secondsAlreadyRun += [[NSDate date] timeIntervalSinceDate:startDate];
startDate = [[NSDate alloc] init];
[sender setTitle:#"Start" forState:UIControlStateNormal];
running = false;
}
}
- (void)updateTime {
if(running == false) return;
//calculate elapsed time
NSTimeInterval currentTime = [NSDate timeIntervalSinceReferenceDate];
NSTimeInterval elapsed = secondsAlreadyRun + currentTime - startTime;
// extract out the minutes, seconds, and hours of seconds from elapsed time:
int hours = (int)(mins / 60.0);
elapsed -= hours * 60;
mins = (int)(elapsed / 60.0);
elapsed -= mins * 60;
int secs = (int) (elapsed);
//update our lable using the format of 00:00:00
timerLabel.text = [NSString stringWithFormat:#"%02u:%02u:%02u", hours, mins, secs];
//call uptadeTime again after 1 second
[self performSelector:#selector(updateTime) withObject:self afterDelay:1];
}
Hope this will help. Thanks
A timer class I created in Swift for a timer program in which a counter is updated every second from a set time. Answered to illustrate the Swift solution and the NSTimer function.
The timer can be stopped and restarted; it will resume from where it stopped. Events can be intercepted by the delegate for start, stop, reset, end and second events. Just check the code.
import Foundation
protocol TimerDelegate {
func didStart()
func didStop()
func didReset()
func didEnd()
func updateSecond(timeToGo: NSTimeInterval)
}
// Inherit from NSObject to workaround Selector bug
class Timer : NSObject {
var delegate: TimerDelegate?
var defaultDuration: NSTimeInterval?
var isRunning: Bool {
get {
return self.timer != nil && timer!.valid
}
}
private var secondsToGo: NSTimeInterval = 0
private var timer: NSTimer?
init(defaultDuration: NSTimeInterval, delegate: TimerDelegate? = nil) {
self.defaultDuration = defaultDuration
self.delegate = delegate
super.init()
}
func start() {
self.timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "updateTimer", userInfo: nil, repeats: true)
self.timer!.tolerance = 0.05
if delegate != nil { delegate!.didStart() }
}
func stop () {
self.timer?.invalidate()
self.timer = nil
if delegate != nil { delegate!.didStop() }
}
func reset() {
self.secondsToGo = self.defaultDuration!
if delegate != nil { delegate!.didReset() }
}
func updateTimer() {
--self.secondsToGo
if delegate != nil { delegate!.updateSecond(self.secondsToGo) }
if self.secondsToGo == 0 {
self.stop()
if delegate != nil { delegate!.didEnd() }
}
}
}
HI I have already created a countdown in second, lets say 10 second, but I want to make it more precise
to 10.0 and display it on a label, how do it do that? Thanks in advance
This is what I have now for the "second" countdown
my NSTimer
counterSecond = 10
NSTimer timer1 = [NSTimer scheduledTimerWithTimeInterval : 1
Target:self selector:#selector (countLabel) userInfo:nil repeats:YES];
-(void)countLabel:
counterSecond --;
self.timerLabel.text = [NSString stringWithFormat #"%d", counterSecond];
I would use a start date/time to keep track of the countdown. Because iOS can delay firing the timer for other tasks.
- (void)countdownUpdateMethod:(NSTimer*)theTimer {
// code is written so one can see everything that is happening
// I am sure, some people would combine a few of the lines together
NSDate *currentDate = [NSDate date];
NSTimeInterval elaspedTime = [currentDate timeIntervalSinceDate:startTime];
NSTimeInterval difference = countdownSeconds - elaspedTime;
if (difference <= 0) {
[theTimer invalidate]; // kill the timer
[startTime release]; // release the start time we don't need it anymore
difference = 0; // set to zero just in case iOS fired the timer late
// play a sound asynchronously if you like
}
// update the label with the remainding seconds
countdownLabel.text = [NSString stringWithFormat:#"Seconds: %.1f", difference];
}
- (IBAction)startCountdown {
countdownSeconds = 10; // Set this to whatever you want
startTime = [[NSDate date] retain];
// update the label
countdownLabel.text = [NSString stringWithFormat:#"Seconds: %.1f", countdownSeconds];
// create the timer, hold a reference to the timer if we want to cancel ahead of countdown
// in this example, I don't need it
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector (countdownUpdateMethod:) userInfo:nil repeats:YES];
// couple of points:
// 1. we have to invalidate the timer if we the view unloads before the end
// 2. also release the NSDate if don't reach the end
}
counterSecond = 10
NSTimer timer1 = [NSTimer scheduledTimerWithTimeInterval : 0.1
Target:self selector:#selector (countLabel) userInfo:nil repeats:YES];
-(void)countLabel:
counterSecond - 0.1;
self.timerLabel.text = [NSString stringWithFormat #"%f", counterSecond];
That should work.
I am writing a countdowtimer application like the timer tab in the clock app of the iPhone. Right now I am having trouble comparing to dates, the 'now' and 'futureDate'.
all the variables are synthesized and are nonatomic and retain.
I have this code right now.
- (IBAction)startTimer:(id)sender {
NSLog(#"startTimer");
pickerView.hidden = YES;
labelView.hidden = NO;
now = [[NSDate alloc] init];
futureDate = [[NSDate alloc] initWithTimeInterval:picker.countDownDuration sinceDate:now];
NSLog(#"Dates.\nNow = (%#) \nfutureDate (%#)", now, futureDate);
timerLabelUpdater = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(labelUpdater) userInfo:nil repeats:YES];
}
- (void)labelUpdater {
if ([now timeIntervalSinceDate:futureDate] < 0.0) {
NSLog(#"YES\nDates.\nNow = (%#) \nfutureDate (%#)", now, futureDate);
} else {
NSLog(#"NO\nNow = (%#) \nfutureDate (%#)", now, futureDate);
}
}
Debugger info:
2011-02-08 16:46:02.449 App[22504:207] startTimer
2011-02-08 16:46:02.451 App[22504:207] Dates.
Now = (2011-02-08 18:46:02 +0000)
futureDate (2011-02-08 18:47:02 +0000)
2011-02-08 16:46:03.451 App[22504:207] YES
And it stay giving me yes "forever".
But if you see the variable hours, they are +2h in the future compared from my clock time. Is this the bug?
Sorry my if was testing the wrong date, comparing the variable now and futureDate the time interval will be the same forever. I replaced the now variable for a [[NSDate alloc] init] in the test. Right now the code works.
if ([[[NSDate alloc]init] timeIntervalSinceDate:futureDate] < 0.0) {
NSLog(#"YES\nDates.\nNow = (%#) \nfutureDate (%#)", now, futureDate);
} else {
NSLog(#"NO\nNow = (%#) \nfutureDate (%#)", now, futureDate);
}
sorry for the stupid question.