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Agenda - What is Wear OS? - LINE app on Wear OS - Challenges - Key takeaways

What is Wear OS?

LINE App History 2021 ? 2014 iPad FirefoxOS Chrome Browser 2012 BlackBerry 2015 Watch OS Windows Mac 2013 Windows Phone Nokia Asha Firefox OS 2011 Android iOS

- Wear OS 3.0 - Standalone app - Has basic features of LINE app - Ensure the security of LINE app - Login by QR Code LINE app on Wear OS

Development process Focus on one or two needs of the target users Share business logic with Android project Make sure to meet Google's standard Use the Multi-APK delivery method because we already have LINE Android app on Play Store Implement Test Publish Design

New Device Specs Optimized for the wrist ~1.5 inch Screen Small ~400mAh Battery Low ~16GB ~1.5GB RAM Memory Low

- New UI/UX - Notifications - Sync data with Android app - Battery usage - Network usage Challenges

New UI/UX

UI/UX - Use Wear OS UI Library from Android Jetpack. - Must test Wear OS app against emulators: Wear OS Square 1.65” and Wear OS Round 1.84”.

BoxInsetLayout - A screen shape-aware ViewGroup

Swipe-to-dismiss gesture - Activities automatically support swipe-to-dismiss. - SwipeDismissFrameLayout.

WearableRecyclerView - WearableRecyclerView RecyclerView WearableRecyclerView

Notifications

Notifications Notifications are bridged Notifications from Android app Notifications of Wear OS app

Notifications on LINE app Installed LINE Android app No LINE notifications on Wear OS Logged in same account No Show LINE notifications on Wear OS Yes Disable bridged notifications from LINE Android app No Connected to Phone via BLE Yes Yes No

Disable bridged notifications

Disable bridged notifications

Sync data with Android app

Need data from LINE Android? - Get quick replies from LINE Android settings. - To check if LINE Android and Wear OS apps are logged in using same account.

Sync data between Android and Wear OS Data Client Message Client Channel Client Data size >= 10KB < 10KB < 10KB Connection type Network Bluetooth Bluetooth Send data from one device to another device No, from the cloud to all the nodes Yes Yes, for both one way requests and bi- directional requests

Get data from Android App WearableListenerService Android Wear OS Bluetooth

Battery usage

Data update on LINE Android time Foreground Background FirebaseMessagingService Fetch new data Fetch new data interval Decrypt data Save data to DB Update UI … onMessageReceived() Show notifications … Fetch new data Decrypt data Save data to DB Update UI …

Data update on LINE Wear OS time Foreground Background Fetch new data Fetch new data interval Decrypt data Save data to DB Update UI … No background services

Battery usage comparison Using Battery Historian Wear OS ~361mAh Android ~4000mAh Used 1.444mAh Used 60.0mAh

Network usage

Network on Smartwatch Mobile data/Wifi Bluetooth Mobile data/Wifi

Reduce network usage - Only show the thumbnail of image, don’t download the original image. - Disable fancy features like animated sticker, gif images. - Limit supported message types.

Network usages Only support some basic types and disable some features Android Wear OS Text Yes Yes Sticker Yes Yes Disabled animated or popup/sound effects Image Yes Yes Only show thumbnail Audio Yes Yes 30 seconds recording duration limit Video Yes No

Network usage comparison When receive same image message Android Wear OS

Memory allocation Memory allocation on the chat screen Android Wear OS

Key takeaways - Content fits within the physical display area: Circle and Square. - Give users the content they need every time they raise their wrist. Optimize for the wrist Pay attention to optimizations - Take full advantage of Android app version: data, Bridged Notifications. - Our users cares much about battery, network, and memory usage. Enough is good as a feast - Focus on one or two needs of the target users.

Thank you