Focus Flow
An Android app that tracks screen time and enforces the limits you set — app limits, schedules, a Shorts/Reels blocker and a smart alarm.
- Layer
- Interface
- Context
- Personal project, preparing for Google Play
- Team
- Solo
- Status
- In progress
- Built with
- Kotlin, Jetpack Compose, Room, WorkManager, UsageStatsManager, AccessibilityService, JUnit
Focus Flow reads Android’s usage events, rebuilds them into app sessions and enforces the rules the user sets: daily limits per app, schedules, session limits, a blocker for short-video feeds and a morning alarm that keeps distracting apps locked until the user is up.
How it is built
- One source of truth for usage. A single sync job turns raw
UsageStatsManagerevents into sessions, splits them by hour and stores hourly rollups in Room. Every screen and the enforcement service read from those tables; nothing else writes usage. - One source of truth for blocking.
RulesEngineis a plain Kotlin class with no Android dependencies. The rules the user edits in the UI are exactly the rules the foreground service evaluates. - Logic separated from the platform. Session reconstruction, hourly splitting, the rules and interval mode live in pure Kotlin domain packages, tested with JUnit without an emulator. Android classes are thin adapters around them.
- Blocking. A foreground service evaluates the rules and shows a full-screen overlay when a limit is hit. An
AccessibilityServicedetects Shorts and Reels feeds. - Time is hard. Day boundaries, rolling 7-day windows and daylight-saving transitions each have explicit handling and tests.
Things I fixed along the way
- ANR errors caused by an accessibility service traversing the whole view hierarchy recursively on the main thread.
- Slow cold starts caused by blocking (
runBlocking,Thread.sleep) initialization in theApplicationclass. - Corrupted statistics for past days, traced to day-boundary and rolling-week calculations.