Open Radar

 
I believe the WKInterfaceTimer is intended to work both as a countdown and count up timer, but currently the timer only supports counting down. The control description in interface builder actually states "Timer - Displays a string that counts up or down to a specified time." But from the detailed class description online, it is clear that the control is currently implemented as a purely countdown timer.

The issue here is that really the only way to build a count up timer that starts from 00:00.0 and counts up is through this class, so it needs to support this.

The only attribute this class has so far for controlling it's behavior is the date. You can set a date (which the header states will be counted up/down toward). Here's how that actually seems to work now though.

If you specify a date with a positive time interval from the current date, say, 3600 seconds (one hour) from now, the timer will start at 59:59 and counts down like you would expect.

If you specify a date with a negative time interval from the current date, say, -3600 seconds (one hour earlier), the timer will start at 1:00:00 and begin counting up, sort of like you would expect. But this behavior isn't really defined. I haven't actually waited an hour to see if it would stop, but I'm still confused why it would start at 1:00:00 instead of 0:00:00 and count up towards 1:00:00.

Let's say I wanted to implement a count up timer that counted up to a maximum of 12 hours. Given the behavior above, I'd probably expect to input -(3600 * 12) as the time interval offset for the WKInterfaceTimer's date parameter. But that results in a timer starting at 12:00:00 and counting up. :(

The other alternative I could see is specify a date of zero, or possibly -1, as the offset to the date, in the hopes that those would result in a timer that counts up starting from 0:00:00. Unfortunately, neither of those result in the desired behavior either. In both cases the timer simply displays "1" and stays there. The same is true until you specify a negative offset greater than or equal to 60. In other words, the timer really doesn't feel like starting anything below a minute of precision. If you specify -60 as the time interval, you'll get a timer that starts at 1:00 and counts up from one minute.

I'd like to see a cleaner interface to the WKInterfaceTimer class that allows you to specify a boolean for "count up or down", for example. At the very least, I'd like to see a documented and working count up behavior that allows a 0 or -1 time interval that supports a count up timer starting at 0:00 or 0:01.