💤 Sleep Tracker

A sophisticated, modern Android application built with Kotlin that enables users to monitor their sleep health, track real-time sleep sessions, and analyze their consistency against personal goals.

Developed as a comprehensive project for the Android Development Lab Experiment.

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🌟 Features

🕒 Smart Tracking

• One-Tap Session: Start and stop sleep tracking with a high-precision chronometer.
• Stage Detection: Logic-based sleep stage monitoring:
  • Light Sleep: The restorative initial 90-minute phase.
  • Deep Sleep: The intensive recovery phase entered after 90 minutes.
• Reset Logic: Easily discard accidental or incorrect sessions.

🎯 Goal Management

• Material TimePicker: A sleek, futuristic interface to set daily sleep targets.
• Persistence: Goals and settings are saved securely in SharedPreferences, ensuring data isn't lost when the app closes.

📊 Advanced Analytics

• Average Calculation: Automatically computes your average rest duration over multiple sessions.
• Goal Comparison: Instant feedback on your sleep performance:
  • Example: "+15m vs goal" (Met) or "-40m vs goal" (Deficit).
• Dynamic UI: The interface adapts its messaging and colors based on your sleep health.

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📱 Screen Breakdown

1. Main Dashboard

The control center of the app. It features a live chronometer, current sleep stage indicator, and quick-glance statistics for the last session and overall averages.

2. Settings Screen

Designed for customization. Users can toggle haptic feedback, enable smart alarms, and adjust their sleep goals via a Material 3 Time Picker.

3. Summary Screen

A dedicated "Done" screen that appears after a session. It provides a deep dive into the session data, compares it against the user's set goal, and offers insights into REM cycle consistency.

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📂 Project Architecture

The app is built using the MVVM (Model-View-ViewModel) architecture pattern, promoting clean separation of concerns and testability.

com.example.sleeptracker
├── model
│   └── SleepSession.kt       # Data structure for sleep entries
├── repository
│   └── SleepRepository.kt    # Single source of truth (SharedPreferences)
├── uiscale                   # UI/View Layer
│   ├── MainActivity.kt       # Main Tracking Logic
│   ├── SettingsActivity.kt   # Goal & App Configuration
│   └── SummaryActivity.kt    # Post-Sleep Data Analysis
├── viewmodel
│   └── SleepViewModel.kt     # Business logic & Data stream management
└── res
    └── layout                # XML UI definitions (ConstraintLayout)

🛠️ Technical Stack

Language: Kotlin

UI Framework: Material Design 3 (Material Components)

Architecture: MVVM

Storage : SharedPreferences (Persistent Key-Value Storage)

Layout Engine: ConstraintLayout for flat, performant UI hierarchies

Components: Chronometer, MaterialCardView, MaterialSwitch, MaterialTimePicker