Google has announced the launch of its Wear OS developer preview programme, targeting its wearable devices (primarily smartwatches) running Wear OS, the spiritual successor to Android Wear. The preview, which is meant to bring some of the headline features of Android P to the wearable platform, includes additions such as a dark system theme, a background activity, limiter, radio deactivation when the watch detects it's not being worn, and much more.
The release of this new developer preview was unveiled via a post on the Android Developer's Blog. Google has highlighted the usefulness of the new included features, such as the much-appreciated addition of a dark theme, which Google say will help improve glanceability. Additionally, apps will no longer be permitted to run in the background unless the watch is being charged., for the purpose of power conservation (this doesn't apply to in-use apps or to your complex wacky watch face of choice).
Additionally, Bluetooth, Wi-Fi, and cellular radios will now be disabled when the watch detects that it's not being worn for an extended period of time; another highly useful battery saving measure. Watches will also no longer automatically connect to Wi-Fi when disconnected from Bluetooth unless an app requires a high-bandwidth network or the watch is being charged.
As for changes unlikely to affect the average consumer, developers are being warned to scale back the use of non-SDK methods, as they will be restricted in the near future to preserve maximum compatibility across the platform.
These features (with the exception of the dark theme) will be rolling out gradually to target devices, with the first two devices eligible for the preview being the Huawei Watch 2 Sport and Watch 2 Classic. System images for these are available to download and are also live on the Android emulator. Separate images for China are also available. Do take care while flashing though; known bugs such as failures to generate error reports are already known and are listed in the release notes, so flash at your own risk.