iOS Timer functionality

[Sergio10]

Hi,

How to create timer? I need every second call some function(e.g. updateTimer)
I developed:

	NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateTimer) userInfo:nil repeats:YES];
...
- (void)updateTimer:(id)sender
{
	NSLog(@"my text\n");
}

But it crashes. What I'm doing wrong?

Thanks.

 

[kainjow]

Use @selector(updateTimer

 

[macfanboy]

scheduledTimerWithTimeInterval:1.0f

why is there an f?

 

[firewood]

why is there an f?

It's C for "make this constant a single precision float", which is a complete and utter waste, since scheduledTimerWithTimeInterval takes a NSTimeInterval === a float double, so the parameter will get converted back to a float double before getting pushed on the stack for the function/method/message invocation anyway.

 

[BlackWolf]

well, in the end it doesn't really matter. you are giving the timer the selector "updateTimer" but you have the method "updateTimer:" - so your method never gets called. but, your method is pretty wrong anyway, because the reference of NSTimer says:

aSelector
The message to send to target when the timer fires.
The selector must have the following signature:

    - (void)timerFireMethod:(NSTimer*)theTimer

if you need to pass additional parameters you must use

scheduledTimerWithTimeInterval:invocation:repeats: