[Xtraz]

Hi I'd like my timer to be reset (to its maximum value) whenever a button is pressed. For example on first press the timer is at 5 seconds,

-(void) buttonPressed
{
timer = [NSTimer scheduledTimerWithTimeInterval:5.0
target:self
selector:@selector(endTimer
userInfo:nil
repeats:NO];
}

But, say 3 seconds later, (2 seconds til time is up) I press the button again it doesn't reset the timer. How do I solve this problem?

Just curious, how would you add to the remaining time of the timer (ie. 3 + 5 = 8 seconds after second press) instead? I'm sure I'm missing the point of NSTimer or something, but it just seems like watchdog timers on microcontrollers are more versatile than it.

Thanks!

[smeger]

Just invalidate it and create it again.

[Xtraz]

Thanks. It worked except for the case that the timer expired by itself before the button is pressed, in which case [timer invalidate] would cause an error because it had already released itself, so I just made a BOOL is_timer_active to keep track of that.

Again just curiously, to actually add say 5 seconds to the timer's remaining time, would I have to add 5 seconds to [timer fireDate] and then use set a new fireDate with that?

[Angus_D]

Originally posted by Xtraz:
Thanks. It worked except for the case that the timer expired by itself before the button is pressed, in which case [timer invalidate] would cause an error because it had already released itself, so I just made a BOOL is_timer_active to keep track of that.

You could just set the pointer to nil from the method the timer fires, then when you call [timer invalidate] it'll just work because messaging nil is allowed.

Again just curiously, to actually add say 5 seconds to the timer's remaining time, would I have to add 5 seconds to [timer fireDate] and then use set a new fireDate with that?

I think so, yes.

[smeger]

Yeah, as Angus said, make your NSTimer instance variable a class variable (defined in your @interface section). When you invalidate it, set it to nil immediately afterwards. Then, you can safely invalidate it again since Cocoa internally converts messaging a nil-object to a "no operation".

Must be early in the morning for me - I can't seem to explain this very clearly.

[Xtraz]

Works perfectly. Thanks guys.