Wear OS by Google developer preview

Posted by Hoi Lam, Lead Developer Advocate, Wear OS by Google

Today we launched the Wear OS by Google developer preview and brought Android P platform features to wearables. The developer preview includes updated system images on the official Android Emulator and a downloadable system image for the Huawei Watch 2 Bluetooth or Huawei Watch 2 Classic Bluetooth. This initial release is intended for developers only and is not for daily or consumer use. Therefore, it is only available via manual download and flash. Please refer to the release notes for known issues before downloading and flashing your device.

In this release, we would like to highlight the following features that developers should pay attention to:

• 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.

Please give us your feedback

We expect to provide several updates to this preview before the final production release. Please submit any bugs you find via the Wear OS by Google issue tracker. The earlier you submit them, the higher the likelihood that we can include the fixes in the final release.