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.
Related
This is not all the code. I have made sure that I have declared everything correctly however the label is not changing as 'seconds' is decreasing.
I'm not sure why as in 'subtractTime' I have made timerLabel.text equal to the string with format using seconds which "should" and is counting down as I use an alert to reset the game and so even though the label isn't changing, I know it is counting down otherwise the alert wouldn't be triggered from 'seconds' equalling 0.
- (void)setupGame;
{
seconds = 30;
count = 0;
timerLabel.text = [NSString stringWithFormat: #"Time: %i", seconds];
scoreLabel.text = [NSString stringWithFormat: #"Score: %i", count];
timer = [NSTimer scheduledTimerWithTimeInterval:1.0
target:self
selector:#selector(subtractTime)
userInfo:nil
repeats:YES];
}
- (void)subtractTime;
{
seconds--;
timerLabel.text = [NSString stringWithFormat:#"Time: %i", seconds];
if (seconds == 0)
{
[timer invalidate];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle: #"Time is up !"
message: [NSString stringWithFormat: #"You Scored %i points", count]
delegate:self
cancelButtonTitle: #"Play Again"
otherButtonTitles:nil];
[alert show];
}
}
#end
Make sure in Storyboard/Interface builder that your label is wired properly to the viewXontroller's .h file. A good way to test this is to "prime" your label on the XIB with something other than "Time:" but instead with something nonsensical like "foo". That way you'll be able to accurately tell if the label is changing at all versus troubleshooting whether or not your Int value isn't showing properly.
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() }
}
}
}
I have this code to change the number in the NSString every five seconds.
How will I keep the numbers running in a loop? It now runs from 1 to 19 ,and stops at the last one (19) with a SIGABRT on the line: label.text = ...
How can I start with the first number displayed (0), before the first timer fires?
Here is the code:
-(IBAction) rotate3
{
NSString *number = [self.dayArray description];
NSArray *array = [[NSArray alloc] initWithObjects: #"0", #"1", #"2",..., #"19",nil];
number = #"0" ;
numberCount++ ;
self.dayArray = array;
[array release];
label.text = [NSString stringWithFormat:#"Day: %# ", [dayArray objectAtIndex :numberCount ]];
}
//and the timer
- (void)viewDidLoad
{
timer=[NSTimer scheduledTimerWithTimeInterval:5.0 target:self selector:#selector(rotate3 )userInfo:nil repeats:YES];
}
Here is my answers:
1)I think, at the last one (19), the numberCount is 20 (numberCount++ ;).
2)Just set the value before scheduling the timer.
add this to your .h file, in your interface (that is, if it isn't already there)
{
NSInteger numberCount
}
Then in your viewDidLoad method, initialize numberCount and the label:
numberCount = 0;
label.text = #"0";
And in your time method, replace:
numberCount++
with
if(numberCount++ > 19)
numberCount = 0;
What is the "number" NSString used for, b.t.w.?
Why have dayArray?
why not something like
label.text = [NSString stringWithFormat:#"Day: %d", numberCount++];
if (numberCount>19) numberCount = 0;
I don't know what you have number count initialized to it should probably be -1 and also reinitialized to -1 . if you wish to iterate thru "Day: 0" ... "Day: 19"
It's not clear.
You could change the -(void)viewDidLoad timer to not repeat
timer=[NSTimer scheduledTimerWithTimeInterval:5.0 target:self selector:#selector(rotate3 )userInfo:nil repeats:NO];
then, conditionally set it up again in the rotate3 method if you still want to change the text 5 seconds later.
try this:
#pragma mark - timer callback
-(IBAction)rotate3
{
[label1 setText:[dayArray objectAtIndex:numberCount]];
numberCount++;
if (numberCount >= [dayArray count])
numberCount = 0;
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
dayArray = [[NSArray alloc] initWithObjects:#"0",#"1",#"2",#"3", nil];
[label1 setText:[dayArray objectAtIndex:0]];
numberCount = 1;
timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(rotate3) userInfo:nil repeats:YES];
// Do any additional setup after loading the view, typically from a nib.
}
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 constantly get malloc error : double freed....
The echoTime function is being called by a button. When I press the button again before the timer ends it gives me the malloc error. When I press the button after the timer finished to start it again, the simulator hangs.
Does anyone know what is wrong with the following piece of code:
-(IBAction)echoTime: (id) sender {
if (gameTimer != nil) {
[gameTimer invalidate];
[gameTimer release];
}
NSInteger secs = 1 * 60;
if (secs != 0) {
NSNumber *elapsedSeconds = [[NSNumber alloc] initWithInt:secs];
NSDictionary *myDict = [NSDictionary dictionaryWithObject:elapsedSeconds forKey:#"TotalSeconds"];
gameTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:#selector(echoIt:) userInfo:myDict repeats: YES];
}
}
-(void)echoIt: (NSTimer *) timer {
NSNumber *num = (NSNumber *) [[timer userInfo] valueForKey:#"TotalSeconds"];
seconds++;
NSInteger sec = [num integerValue] - seconds;
NSInteger minutes = sec / 60;
[gameTimeLabel setText:[NSString stringWithFormat:#"%02i:%02i", minutes, sec-(60*minutes)]];
if (sec == 0) {
[self playSound:#"Horn"];
[gameTimer invalidate];
}
}
NSNumber *elapsedSeconds = [[NSNumber alloc] initWithInt:secs];
In general dont alloc NSNumbers and a NSDictionary (and NSArray,NSSet) always retains the objects it is given (and releases them too when it should).
try...
NSNumber *elapsedSeconds = [NSNumber numberWithInt:secs];
It'll stop the retain cycle you've got and might stop the crash.
Also irrelevant but stylewise.
NSInteger secs = [[[timer userInfo] valueForKey:#"TotalSeconds"] intValue];
Is a little more efficient.