Google is releasing the first Wear OS developer preview today, since it was rebranded from Android Wear. The new update brings Android P features to smartwatches, and today"s developer preview is only available for the Huawei Watch 2.
Here are the new features that Google called out in its blog post:
Restriction related to non-SDK methods and fields: To improve app compatibility, Android P has started the process of restricting access to non-SDK methods and fields. Developers should make plans to migrate away from these. If there is no public equivalent for your use case, please let us know.
Dark UI system theme: To enhance glanceability, Wear OS has switched to a UI theme with a darker / black background for the notifications stream and system launcher since the start of the year. This is now also the default for the system theme and should improve the glanceability for wear apps. Developers should check the accessibility of their app"s UI after this change.
Limited background activity: To improve power, apps will no longer be allowed to run in the background unless the watch is on the charger. Developers should note that Wear OS is going further with Android"s app standby feature than some other form factors. Exceptions to this include watch faces and complications that the user currently has selected. This feature will be rolled out gradually in the developer preview, so you may not see it immediately on your device, but should build your apps accordingly by removing background services.
Turning off radios when off body: To improve power, bluetooth, WiFi, and cellular radios will be turned off when the watch is detected to be off body for an extended period of time. Again, this feature will be rolled out gradually so you may not initially see it on your device. If this feature causes challenges in your development process, you can disable the feature via adb; please follow the instructions in the release notes.
WiFi off when BT is disconnected: To improve power, the device will no longer automatically connect to wifi when disconnected from bluetooth. Exceptions include if an app is requesting a high bandwidth network or if the watch is on the charger. This feature will be rolled out gradually so you may not initially see it on your device.
There are also some known issues to be aware of:
In the Wear OS companion app, tapping "Report wearable bug" will appear to work, but no bug report is actually generated. We recommend using adb bugreport as a workaround.
Accepting a phone call using the watch does not always succeed. If it does not succeed, the user needs to accept the call from the phone directly.
A "Detected problems with API compatibility" error sometimes appears after pairing or launching a pre-loaded app. That error message disappears after a short time and does not impact usability.
In the Settings menu on the watch and in the emulator, the "Take bug report" option is displayed twice. To take a bug report, try using each of the two options, because only one is functional. When you tap the functional option, a toast is displayed, showing that a bug report is being generated.
In the China version, voice input causes an app to crash. This occurs, for example, with voice search or using voice to add a reminder, because this functionality uses voice input APIs. For testing, use keyboard or handwriting input instead of voice input.
The Wear app store in the China version does not work. Developers will be unable to update or install new apps via that channel. We recommend that developers use adb to side-load their application for testing, as a workaround.
Unfortunately, Google didn"t provide any official timeline for when this update will be released to everyone, or when future developer previews will be offered. For example, when Google launched the Android P preview, it presented the roadmap for when it will be released.
If it"s anything like last year"s Oreo update, we"ll see it in December, or a couple of months after the Android P release for phones. We"ll find out more about what"s coming in May, when Google holds its I/O 2018 developer conference.