A tech talk on how to create a watch face application for Android Wear where the focus isn't on the timekeeping, but on content.

1. Trending Time
See what’s hot on Twitter - on your wrist!
A primer on data-driven watch face development for Android Wear

2. Project goals
● Build a content-centric watch face
● Use best practices, but steer slightly off-
course from conventions in Google’s sample
app
● No user OAuth - just install, activate & enjoy!

3. A funny thing happened...
● Watch Face API launched December 2014
● Seemingly everyone built one
● Not many data-driven projects
● I wanted to do a community tutorial
● I suck at art

4. Tons of amazing visualizations...

5. ...but content is what I’m about

6. A utility delivering utility
● Surfaces top trends
● High entertainment
value
● Usually hilarious, often
informative, sometimes
helpful

7. This is where wearables rock
● Microinteractions: <= 3-second sessions
● Stay in the know without leaving the moment
● Not bothered by constant notification pelting

8. Variation on a theme
● The core element of designing watch faces
is the creative expression of time

9. But again...
Source:
http://explodingdog.com/title/icantdraw.html

10. Variation on a theme
● With Trending Time, the timekeeping
function takes a backseat to the watch being
a portable stage for quick, relevant
information

11. One line & you’re done
WatchFaceStyle.Builder(this)
.setShowSystemUiTime(true)
...
.build();

12. Account for the peek card
.setCardPeekMode(WatchFaceStyle.PEEK_MODE_SHORT)

13. Available canvas real estate

14. Immediate dividends :)

15. Immediate dividends :(

16. How is a watch face made?
● If you said…
○ “It’s like building a live wallpaper!”
○ “It’s like building a game!”
○ “It’s like building an animation loop!”

17. Ding ding ding!
Source:
http://canuckpost.
com/2013/10/tale-of-two-
listings/

18. Under the hood: two apps
● All cloudtalk happens on the phone
○ Background service calls Twitter’s API
○ AlarmManager schedules hourly invocations
○ Updated trending topics stored in a DataMap
● Data auto-syncs to watch over Bluetooth
○ If devices lose pairing, data is buffered & sent when
connectivity is restored

19. ● Wearable service listens for changes
○ Content persisted in SharedPreferences
○ (Will eventually migrate to a BroadcastReceiver)
● Redraws only when screen is active
○ Invalidate display in onPropertiesChanged event
Under the hood: two apps

20. Usage
1. Launch mobile app
2. Tap “Start updater”
3. Close mobile app
4. Select “Trending
Time” watch face

21. The engineering trifecta
● Performant
○ No need for FPS stress
○ Avoids interval- or tick-based loops
● Scalable
○ Proxy handler minimizes API calls; preserves quota
● Battery-friendly
○ Diverts from AsyncTask-based timer pattern
○ Same impact in interactive mode & ambient mode

22. Drawbacks
● Watch faces aren’t interactive
○ A service, not an activity
○ Read-only relay
● Let the user drill-down into actual tweets
○ Trends selected on the watch handled on the phone
by Twitter’s app or Chrome

23. Roadmap: UI goodies
● Topics presented
as a tag cloud
while maintaining
glanceable ethos
● User-defined
trending regions
● Contextual inputs

24. 100% free!
play.google.com/store/apps/details?id=wearables.jasonsalas.com.trendingtime

25. github.com/jasonsalas/TrendingTimeForAndroidWear
100% open source!

26. Shameless product plug
@jasonsalas
google.com/+JasonSalas
Designing & Developing
for Google Glass