XStopwatch & XTimer are a pair of apps (installed together) for Android Wear that implement a stopwatch (counting upward from zero) and a timer (counting down and buzzing at zero). What makes them special is that they publish their information for compatible watchfaces to display. For an example watchface that works together with XStopwatch & XTimer, you may enjoy

CalWatch

.

Note: this app runs on Android Wear watches (e.g., LG G Watch, Samsung Gear Live, Motorola 360) and does NOT run on Samsung's Tizen watches (Gear Fit, Gear 2, Gear S), Pebble watches, or any other smartwatch devices.

A few cool features

• You can say "Ok Google, set a timer for five minutes" and XTimer will do the right thing. You can also say "Ok Google, start stopwatch".

• XStopwatch and XTimer will pop up notifications with a working pause/play button. You can swipe down to hide them, as with any notification, but you'll still know the timer or stopwatch is going when you're using a watchface that works with them.

• When you're running XStopwatch, you can click on the timer icon to switch to XTimer, and vice versa.

• Unlike many other timers, XStopwatch and XTimer never accidentally reset themselves because you perhaps dismissed the notification. You can reboot your watch, and the timer or stopwatch will be just like you left them. Of course, you can always go to the app and hit "X" to reset things.

Privacy

XStopwatch & XTimer collect no personal information. They don't even require Internet permissions.

Wear Developers

The specification and example code for how a watchface listens to XStopwatch & XTimer is open and available for all Wear developers and the source code to XStopwatch & XTimer is also open source, which will help you particularly if you're working on your own stopwatch or timer app. See the link below for details.

http://www.cs.rice.edu/~dwallach/xstopwatch/