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MobileHealthAndroid
KotlinJetpack ComposeForeground ServicesBroadcast ReceiversJetpack DataStoreMVVM

Rest Your Eyes

Native Android application designed to prevent eye strain caused by prolonged mobile device usage.

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The Problem

Eye strain from prolonged, continuous mobile screen use, with no built-in way to track real screen-on time or receive proactive rest reminders — and Android 14+'s stricter background service restrictions make naive polling solutions unreliable.

The Solution

A native Android app that enforces the 20-20-20 rule by tracking real screen-on time via a Foreground Service and BroadcastReceivers (ACTION_SCREEN_ON/OFF), pausing automatically when the device is locked to avoid battery drain. It overlays a gentle SYSTEM_ALERT_WINDOW reminder with customizable sound alerts and auto-dismiss, and declares the Android 14+ `health` foreground service type so the OS never kills the monitor mid-session.

Key Learnings

  • Building an app capable of tracking real device usage (screen on/off time).
  • Using Foreground Services and Broadcast Receivers in Android for background monitoring.
  • Implementing system-level overlay notifications (SYSTEM_ALERT_WINDOW) to proactively interact with the user.

Background Architecture & Screen Time Tracking

Rest Your Eyes enforces the 20-20-20 optical rule (rest eyes for 20 seconds every 20 minutes of continuous screen use) via a high-efficiency native Android background service:

  • Foreground Service & BroadcastReceivers: Real-time state tracking listening to ACTION_SCREEN_ON and ACTION_SCREEN_OFF events to aggregate only genuine active screen-on time.
  • Proactive Overlays (SYSTEM_ALERT_WINDOW): Renders a gentle, translucent Jetpack Compose overlay prompting eye relaxation without forcibly crashing active tasks.

Battery & Resource Optimization

  • Zero Battery Drain when Locked: The timer automatically pauses when the device is locked or asleep, avoiding CPU WakeLocks and preserving battery longevity.
  • Android 14+ Compliance (FOREGROUND_SERVICE_HEALTH): The Foreground Service explicitly declares the health service type, satisfying Android 14+’s stricter background process restrictions and preventing the OS from killing the monitor during active sessions.