⏱️ Flutter Stopwatch: Precision Timer & Lap Analyzer

This is a full-featured Stopwatch application built using pure Dart and Flutter. I wanted to create a reliable utility that handles accurate timing, lap analysis, and background operation without needing any external packages.

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🎥 Demo Video

Watch this short video to see the app in action, showing the core timing, lap recording, how the lap analysis modes work, and the dark/light theme toggle.

rishab-ms-stopwatch-assignment-recording.1.mp4

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⭐ Key Features & Technical Details

1. Accurate Timing, Even in the Background

The app is built to be totally reliable—you won't lose time if you minimize it.

• The Engine: It uses the standard dart:async's Stopwatch for the core time tracking, which is highly accurate.
• Handling Minimizing: The app listens for when it's moved to the background (paused) and when it comes back (resumed) using WidgetsBindingObserver. When minimized, the timer that updates the UI is stopped to save battery, but the underlying Dart Stopwatch keeps ticking perfectly. When you return, the time display immediately jumps to the correct, elapsed time.
• Smooth Display: We use Timer.periodic to update the UI very frequently (e.g., every 30 milliseconds), making the time display look smooth.

2. Better Lap Analysis

The list of recorded laps offers clear, useful feedback.

• Configurable Views: You can switch between display modes:
  • Highlight: Automatically colors the fastest lap (Green) and the slowest lap (Red) so you can quickly see your extremes.
  • Percentage Change: Shows you how much faster (down arrow) or slower (up arrow) the current lap was compared to the one right before it.

3. Simple State and Code

I kept the state management simple and clean, as no external packages were allowed.

• Built-in State: All data—the current time, all lap records, and settings—is handled inside the main Widget using only the native setState() method.
• Theming: The app supports both light and dark modes, which you can switch via a settings option.

4. Attention to Detail (UI/UX)

• Stable Digits: The main clock uses a special font feature (FontFeature.tabularFigures()) to ensure all numbers have the same width. This prevents the time from "jumping" side-to-side as the numbers change.
• Tactile Feel: Buttons use HapticFeedback for a light vibration when pressed, giving it a more native app feel.
• Clean Transitions: The Start/Stop button uses an AnimatedSwitcher to change its text and color smoothly.

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📁 Project Structure

The entire logic and interface live in one main file for ease of use.

. ├── lib/ │ ├── app_theme.dart # Where the light and dark themes are defined. │ ├── main.dart # The app entry point, handles the theme state. │ └── stopwatch_screen.dart # The main file. Contains all logic, state, and UI. └── README.md

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🚀 How to Run

1. Clone this repository:

   git clone [Your Repository URL]

2. Go into the project folder:

   cd [Project Name]

3. Run the application on an emulator or connected device:

   flutter run