Google's wearable OS also will shift over to the L release once ready
It was sort of a surprise — and a bit of a disappointment, to be perfectly honest — when Android Wear launched without a properly supported way to add custom watch faces to the likes of the LG G Watch, Samsung Gear Live and, eventually, the Moto 360. We've talked a little bit about how custom watch faces were coming, however, and indeed they have — as standalone apps. But that obviously was a workaround, as there's no real API available for custom watch faces.
Overnight, Wayne Piekarski, a senior developer advocate at Google, explained what's up with custom watch faces on Android Wear. The short version is that, no, there's not an official API yet, and watch faces are a little complicated because of the way they interact with the card stream and are contained inside another process. An API is coming, however, and we should see it along with the L release later this year.
And, yes, that (unsurprisingly) means Android Wear will be running L.
Custom watch faces are activities running inside another process. However, they have some special considerations due to interactions with the stream and always-on ambient mode--including using a shorter peek card, moving the status indicators for battery and mute, and rendering the faces differently in ambient mode. Right now, without an official API, making a really great watch face currently takes a fair bit of tweaking.
We are working to make this as simple as possible for you so that it's easy to make good-looking faces that work well across multiple form factors, conserve battery, and display the user's card stream nicely. Some of these changes won't be ready until we migrate Android Wear to the Android L release later this year, but don't fret: they're coming!
Piekarski recommends that developers not just publish standalone watch faces to Google Play wholesale, but instead to use the beta and alpha channels, and that watch faces cobbled together today might well not work once Android Wear shifts to L.
You can read Piekarski's full post here.