Note: To access all shared projects, get information about environment setup, and view other guides, please visit Explore-In-HMOS-Wearable Index.

How To Build Cloud File Sync

This codelab demonstrates how to build Cloud File Sync, a HarmonyOS wearable app for an offline-first cloud file synchronization workflow. It shows cloud sync/cache flows, file sharing permissions, environment path handling, queued transfers, conflict handling, and compact watch navigation.

Preview

Use Cases

• Sync watch files with cloud storage while handling offline and online states.
• Queue uploads and downloads, then batch sync when connectivity returns.
• Share synced files from the watch to a phone with URI permission grants.
• Review transfer progress, retry failed syncs, and resolve simple file conflicts.

Technology

Stack

• Languages: ArkTS, ArkUI
• Frameworks: HarmonyOS SDK 6.0.1(21)
• Tools: DevEco Studio (HarmonyOS NEXT toolchain), Hvigor
• Libraries:
  • @kit.AbilityKit
  • @kit.CoreFileKit
  • @ohos.file.cloudSync
  • @ohos.fileshare
  • @ohos.file.environment

Required Permissions

• ohos.permission.FILE_ACCESS_PERSIST

  Required when persisted file share permissions are available on the target device.

Directory Structure

entry/src/main/ets/
|---entryability
|   |---EntryAbility.ets
|---entrybackupability
|   |---EntryBackupAbility.ets
|---model
|   |---SyncModels.ets
|---pages
|   |---ErrorPage.ets
|   |---Index.ets
|   |---QueuePage.ets
|   |---StartPage.ets
|   |---TransferPage.ets
|---service
|   |---CloudSyncService.ets
|   |---ConflictResolver.ets
|   |---EnvironmentPathService.ets
|   |---FileShareService.ets
|   |---OfflineQueueService.ets
|   |---SyncCoordinator.ets
|   |---SyncCoordinatorStore.ets
|---util
|   |---Constants.ets

Constraints and Restrictions

Supported Device

• Huawei Watch 5

Additional Notes

• The app name and project name are how-to-build-cloud-file-sync-on-watch.
• Navigation uses Navigation and NavPathStack instead of the deprecated Router API.
• Placeholder media resources are intentionally minimal.

License

how-to-build-cloud-file-sync-on-watch is distributed under the terms of the MIT License. See the LICENSE for more information.