Except for the reschedule after each fire, and the CFAbsoluteTimeGetCurrent call This is pretty much what I tried. I had done it with [[NSDate date] timeIntervalSince1970] which might be a hair longer than a CF call.
I will give it a whirl with this approach and compare. At this point it's curiosity. But I've learnt dispatch timer in the process which will come in handy in the future for some non GUI things. Thanks to all Sent from my iPhone On 2013/07/28, at 11:28, Andy Lee <[email protected]> wrote: > On Jul 27, 2013, at 9:57 PM, Andy Lee <[email protected]> wrote: >> I'm trying again, this time creating a new NSTimer each time as suggested by >> Scott Ribe. Will let it run a while and see if I notice any drift. > > Looks pretty solid after several minutes -- as I would expect. To repeat > Scott's suggestion: > >> Personally, I'd probably just do a non-repeating timer, set to fire at the >> next second roll-over. Alloc'ing, scheduling and releasing 1 timer per >> second is not a lot of overhead. > > I didn't take my own suggestion to add .001 and it worked fine, though for > all I know it might have a problem once every 10,000 times the app is run. > > I stole Rick Mann's code and replaced trunc() with round(). > > --Andy > > ========== > > @implementation AppDelegate > > - (void)applicationDidFinishLaunching:(NSNotification *)aNotification > { > [self _resetTimer]; > } > > - (void)_resetTimer > { > CFAbsoluteTime fireDateAbs = round(CFAbsoluteTimeGetCurrent() + 0.5); // > Round to the next second > NSDate *fireDate = [NSDate > dateWithTimeIntervalSinceReferenceDate:fireDateAbs]; > > [[self timer] invalidate]; > [self setTimer:[[NSTimer alloc] initWithFireDate:fireDate > interval:1.0 > target:self > selector:@selector(_timerDidFire:) > userInfo:nil > repeats:NO]]; > [[NSRunLoop currentRunLoop] addTimer:[self timer] > forMode:NSRunLoopCommonModes]; > } > > - (void)_timerDidFire:(NSTimer *)theTimer > { > [self _updateTimeDisplay]; > [self _resetTimer]; > } > > - (void)_updateTimeDisplay > { > NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; > > [dateFormatter setTimeStyle:NSDateFormatterMediumStyle]; > [dateFormatter setDateStyle:NSDateFormatterNoStyle]; > > NSString *timeString = [dateFormatter stringFromDate:[NSDate date]]; > > [[self textField] setStringValue:timeString]; > } > > @end > > _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
