NSTimer in label

[kieran12]

Hey guys. I can't seem to work this one out at all. I've set up an NSTimer like this:

	NSTimer *time = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];

I have a label called timeLeft. I want it to count to down from 30 seconds to zero using the NSTimer. I can't figure out how to get the value of the NSTimer however. I have a variable int countdown set up to store the value but I can;t figure out how to retrieve it.

Any help appreciated.

[kieran12]

I have tried this still with no success:

NSTimer *time = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];	
	countdown = [time fireDate];
	
	
}

-(void) onTimer{
	
	timeLeft.text = [NSString stringWithFormat:@"%i", countdown];
	
}

Any ideas?

[exorcyze]

The timer itself doesn't keep any values ( like time elapsed ) - you'll have to create a variable yourself and update it inside the event when the timer fires.

[kieran12]

How do i do that? Is it similar to the code i just posted above?

[kieran12]

Ok here is the code I have got so far. Everything builds fine and works except the label with the countdown won;t update. Please help.

-(void)timer{
	
	time = 30.0;
	timer = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(countDown) userInfo:nil repeats:YES];	
	
}
-(IBAction)startGame:(id)sender{
	
	
	
	[mainView timer];
	
	
}



-(void) updateLabel{
	
	timeLeft.text = [NSString stringWithFormat:@"%i",time];
	
}

-(void)countDown {
	time = time - 1;
	if (time == 0.0) {
		[timer invalidate];
	}
	[mainView updateLabel];
}

[kieran12]

Ok finally figured it out. There was a mistake in the last bit of code I posted. timerWithInterval should have been scheduledTimerWithInterval. It is now working

[Steaps]

I have used this tutorial before, it worked well, and it is exactly what you are looking for.
Welcome to the iPhone Development Central Website!
Just skip the animation part, but the countdown timer is there.

EDIT: Oh, you got it working.

[eski]

i did this by following the tutorial but even though iv put in

time = time - 1;

it counts down in 4s! i have no idea why and have tried changing the numer but it just times 4 by what numer i put in

e.g time = time - 4; makes it count down in 16s

any one know what could be the problem??

[macack]

Originally Posted by eski

i did this by following the tutorial but even though iv put in

time = time - 1;

it counts down in 4s! i have no idea why and have tried changing the numer but it just times 4 by what numer i put in

e.g time = time - 4; makes it count down in 16s

any one know what could be the problem??

Bump... I am doing a countup routine (vs. the above countdown) and my label seems to be incrementing by 4 every seconds. Any solutiosn for this?

Thx.

[rdominelli]

Originally Posted by macack

Bump... I am doing a countup routine (vs. the above countdown) and my label seems to be incrementing by 4 every seconds. Any solutiosn for this?

Thx.

Don't use a counter. Instead use now + 30 seconds and figure out the difference.

float period = 30;

self.myAlarmDate = [[NSDate alloc] initWithTimeIntervalSinceNow:(NSTimeInterval)period];

Then on your timer tick

NSTimeInterval tmptimeleft = [self.myAlarmDate timeIntervalSinceNow];

label.text = [NSString StringWithFormat:@"%f",tmptimeleft];

NSTimeInterval is actually a double so format it as you want.

Rich