🎯 UI Skeleton Factory

A powerful Flutter package that automatically generates Skeleton Loading UI from any existing Flutter Widget without manually writing skeleton layouts.

✨ Features

🎯 Automatic Generation: Convert any widget to skeleton with zero configuration
🎨 Layout Preservation: Maintains original widget sizes and structure
✨ Shimmer Animation: Optional smooth shimmer effect for visual feedback
⚡ Performance: Optimized for smooth scrolling and minimal overhead
🔧 Flexible API: Multiple ways to use (widget, static, extension)
🎭 Smart Mapping: Intelligently maps widgets to appropriate skeleton representations
📦 Lightweight: No heavy dependencies, pure Flutter implementation

🚀 Quick Start

Installation

Add to your pubspec.yaml:

dependencies:
  ui_skeleton_factory: ^0.0.1

Then run:

flutter pub get

Basic Usage

There are three ways to use UI Skeleton Factory:

SkeletonFactory(
  isLoading: true,
  child: ProductCard(product: product),
)

Method 2: Skeleton.from() Static Method

Skeleton.from(
  ProductCard(product: fakeProduct),
)

Method 3: Extension API

ProductCard(product: product).skeleton(isLoading: true)

📖 Comprehensive Examples

Example 1: Product Card with Skeleton

import 'package:flutter/material.dart';
import 'package:ui_skeleton_factory/ui_skeleton_factory.dart';

class ProductScreen extends StatefulWidget {
  @override
  State<ProductScreen> createState() => _ProductScreenState();
}

class _ProductScreenState extends State<ProductScreen> {
  bool _isLoading = true;
  Product? _product;

  @override
  void initState() {
    super.initState();
    _loadProduct();
  }

  Future<void> _loadProduct() async {
    // Simulate API call
    await Future.delayed(Duration(seconds: 2));
    setState(() {
      _product = Product(/* ... */);
      _isLoading = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Product Details')),
      body: SkeletonFactory(
        isLoading: _isLoading,
        child: ProductCard(product: _product ?? Product.placeholder()),
      ),
    );
  }
}

Example 2: ListView with Skeleton Items

ListView.builder(
  itemCount: isLoading ? 10 : items.length,
  itemBuilder: (context, index) {
    if (isLoading) {
      return Skeleton.from(
        UserListTile(user: User.placeholder()),
      );
    }
    return UserListTile(user: items[index]);
  },
)

Example 3: Using Extension API

Column(
  crossAxisAlignment: CrossAxisAlignment.start,
  children: [
    Text('Title').skeleton(isLoading: isLoading),
    SizedBox(height: 8),
    Text('Subtitle').skeleton(isLoading: isLoading),
    SizedBox(height: 16),
    ElevatedButton(
      onPressed: () {},
      child: Text('Action'),
    ).skeleton(isLoading: isLoading),
  ],
)

Example 4: Conditional Skeleton

// Using skeletonIf for cleaner conditional logic
Text('Hello World').skeletonIf(isLoading)

// Equivalent to:
// isLoading ? Skeleton.from(Text('Hello World')) : Text('Hello World')

⚙️ Configuration

Custom Colors and Appearance

SkeletonFactory(
  isLoading: true,
  config: SkeletonConfig(
    shimmer: true,
    baseColor: Colors.grey[300],
    highlightColor: Colors.grey[100],
    shimmerDuration: Duration(milliseconds: 1500),
    borderRadius: 8.0,
  ),
  child: MyWidget(),
)

Performance Mode (No Shimmer)

For better performance in lists or complex layouts:

// Using predefined performance config
Skeleton.fast(MyWidget())

// Or custom config without shimmer
SkeletonFactory(
  isLoading: true,
  config: SkeletonConfig(shimmer: false),
  child: MyWidget(),
)

Global Configuration

You can use SkeletonConfig.defaultConfig or SkeletonConfig.performanceConfig:

// Default with shimmer
Skeleton.auto(MyWidget())

// Performance mode without shimmer
Skeleton.fast(MyWidget())

🎨 Supported Widgets

UI Skeleton Factory intelligently maps Flutter widgets to skeleton representations:

Original Widget	Skeleton Representation
`Text`	Rectangular bar with font-based height
`Image` / `Image.network`	Solid container box
`Icon`	Circle
`CircleAvatar`	Circle matching avatar size
`ElevatedButton` / `TextButton`	Rounded rectangle
`FloatingActionButton`	Circle
`Card`	Container with rounded corners
`ListTile`	Complete tile layout with leading/title/subtitle
`Checkbox` / `Radio` / `Switch`	Small box/circle
`Row` / `Column`	Preserves layout and spacing
`Stack`	Maintains positioning
`Padding` / `Center` / `Align`	Preserves layout constraints
`Expanded` / `Flexible`	Maintains flex properties

Layout Preservation

The package automatically preserves:

✅ Widget dimensions (width & height)
✅ Padding and margins
✅ Alignment and positioning
✅ Flex properties (Expanded, Flexible)
✅ Row/Column structure and spacing
✅ Stack positioning

🛠️ Advanced Usage

If you want complete control, provide a custom skeleton:

SkeletonFactory(
  isLoading: true,
  skeleton: MyCustomSkeletonWidget(),
  child: MyActualWidget(),
)

Using Individual Skeleton Components

import 'package:ui_skeleton_factory/ui_skeleton_factory.dart';

// Skeleton line (for text)
SkeletonLine(
  config: SkeletonConfig(),
  width: 150,
  height: 16,
)

// Skeleton avatar (circular)
SkeletonAvatar(
  config: SkeletonConfig(),
  size: 40,
)

// Skeleton box (for images)
SkeletonBox(
  config: SkeletonConfig(),
  aspectRatio: 16 / 9,
)

// Generic skeleton container
SkeletonContainer(
  width: 100,
  height: 50,
  config: SkeletonConfig(),
  borderRadius: 8,
  isCircular: false,
)

Extension Methods for Specific Widgets

// Text to skeleton line
Text('Title').toSkeletonLine(widthFactor: 0.8)

// Icon to skeleton circle
Icon(Icons.star).toSkeletonCircle()

// Image to skeleton box
Image.network('url').toSkeletonBox(aspectRatio: 16/9)

// CircleAvatar to skeleton avatar
CircleAvatar(radius: 20).toSkeletonAvatar()

📐 Architecture

The package follows a clean, modular architecture:

lib/
 ├─ core/
 │   ├─ skeleton_parser.dart      // Traverses widget tree
 │   ├─ widget_mapper.dart        // Maps widgets → skeletons
 │   ├─ size_resolver.dart        // Preserves layout sizes
 │   └─ skeleton_context.dart     // Configuration
 ├─ widgets/
 │   ├─ skeleton_container.dart   // Base skeleton components
 │   ├─ shimmer_effect.dart       // Shimmer animation
 │   ├─ skeleton_wrapper.dart     // Loading wrapper logic
 │   ├─ skeleton_factory.dart     // Main widget API
 │   └─ skeleton.dart             // Static API
 └─ extensions/
     └─ skeleton_extension.dart   // Extension methods

🎯 Design Principles

Zero Configuration: Works out of the box with sensible defaults
Layout Preservation: Skeletons match original widget dimensions
Performance First: Optimized for lists and complex layouts
Flexible API: Multiple usage patterns for different preferences
Type Safety: Full Dart type safety and null safety support

🧪 Testing

The package includes comprehensive tests covering:

Widget mapping logic
Layout preservation
Configuration handling
Extension methods
Edge cases and error handling

Run tests with:

flutter test

📱 Example App

The package includes a full example app demonstrating:

Basic Demo: Simple widgets with skeleton
Product Card: Real-world e-commerce card
ListView Demo: Scrollable list with skeleton items
Extension API: Using extension methods
Custom Config: Custom colors and settings

Run the example:

cd example
flutter run

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🌟 Show Your Support

If you find this package useful, please give it a ⭐️ on GitHub!

📮 Feedback

For bugs, questions, and feature requests, please create an issue on GitHub.

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