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

How To Use Timer Functionality

This application demonstrates habit tracking with timer functionality for HarmonyOS wearable devices. It uses the Preferences API for key-value persistence and RelationalStore for session history, and provides a wearable-optimized interface for tracking time spent on daily habits like reading, exercise, meditation, study, and practice.

Preview

Use Cases

• Daily Habit Tracking: Track time spent on important habits with automatic daily reset at midnight.
• Habit Selection: Swipe left or right on the main screen to switch between habits. The Digital Crown also cycles through habits with a degree-based threshold to prevent accidental skips.
• Focus Timer: Use as a stopwatch to measure time spent on activities with start/stop/reset controls. The timer continues running in the background when the wrist is lowered.
• Progress Monitoring: View today's duration and lifetime total for each habit on the main screen.
• Session History: Browse the last 7 days of logged sessions per habit with an inline bar chart.
• Session Notifications: Receive a wrist notification when a session is stopped, confirming the habit name and duration logged today.

Technology

Stack

• Languages: ArkTS
• Frameworks: HarmonyOS SDK 5.1.0 (API 18)
• Tools: DevEco Studio 5.1.0 or later
• Libraries:
  • @kit.AbilityKit,
  • @kit.ArkUI,
  • @kit.ArkData (Preferences API, RelationalStore),
  • @kit.BackgroundTasksKit,
  • @kit.NotificationKit

Required Permissions

• "ohos.permission.KEEP_BACKGROUND_RUNNING"

Directory Structure

entry/src/main/ets/
|---entryability
|   |---EntryAbility.ets              // Application lifecycle, notification permission request
|---constants
|   |---DbConstants.ets               // RelationalStore table and column name constants
|   |---StorageKeys.ets               // Preferences storage key constants
|---models
|   |---DefaultHabits.ets             // Default habit definitions
|   |---Habit.ets                     // Habit, TimerState, DailyRecord interfaces
|---pages
|   |---HistoryPage.ets               // 7-day session history with bar chart
|   |---Index.ets                     // Main UI — swiper navigation, timer, today/total display
|---services
|   |---HabitService.ets              // Timer logic, background task, session notification
|   |---HistoryService.ets            // RelationalStore wrapper for session history
|   |---PreferencesService.ets        // Key-value persistence wrapper
|---viewmodels
|   |---HistoryViewModel.ets          // History page state and data logic
|   |---IndexViewModel.ets            // Main page state, timer control, crown navigation

Constraints and Restrictions

Supported Device

• Huawei Watch 5

Limitations

• Habits are pre-configured in code; no UI to add/remove/edit habits.
• Session history is stored on-device only; no phone sync.
• Background task uses dataTransfer mode — the closest wearable-supported mode for timer persistence.
• Notification permission must be granted by the user at first launch; session-end notifications will not appear if denied.

License

HabitTimer is distributed under the terms of the MIT License.

See the LICENSE for more information.