On the Wear OS, How We developed LINE Application

Thuy Phan
LINE Vietnam / App Engineering / Android Engineer

https://linedevday.linecorp.com/2021/ja/sessions/136
https://linedevday.linecorp.com/2021/en/sessions/136
https://linedevday.linecorp.com/2021/ko/sessions/136

Transcript

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

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3. What is Wear OS?
   

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4. 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
   

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5. - 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
   

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6. 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
   

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

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

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9. New UI/UX
   

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10. 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”.
    

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11. BoxInsetLayout
    - A screen shape-aware ViewGroup
    

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

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13. WearableRecyclerView
    - WearableRecyclerView
    RecyclerView WearableRecyclerView
    

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14. Notifications
    

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

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16. 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
    

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17. Disable bridged notifications
    

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18. Disable bridged notifications
    

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19. Sync data with Android app
    

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20. 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.
    

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21. 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
    

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22. Get data from Android App
    WearableListenerService
    Android Wear OS
    Bluetooth
    

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23. Battery usage
    

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24. 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
    …
    

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25. 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
    

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

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27. Network usage
    

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

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29. 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.
    

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30. 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
    

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31. Network usage comparison
    When receive same image message
    Android
    Wear OS
    

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32. Memory allocation
    Memory allocation on the chat screen
    Android Wear OS
    

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33. 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.
    

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34. Thank you
    

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