quick_change 🧩

A lightweight, intuitive state management solution for Flutter.
Effortlessly manage state transitions with simple, type-safe states and powerful listening and building capabilities.

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quick_change is designed to simplify state management in Flutter apps, making it suitable for both small and medium-scale applications, with the flexibility to extend for large apps. This package provides easy-to-use state controllers, built-in state types, and intuitive UI listening and building capabilities.

Features ✨

• Simple and Lightweight: Manage state without heavy dependencies.
• Flexible States: Use predefined states like QuickLoading, QuickData, and QuickError.
• Easy Listeners: React to state changes with a clean, intuitive listener API.
• Modular Design: Suitable for modular and scalable Flutter applications.
• Optimized for Performance: Only rebuilds widgets when necessary.

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Table of Contents 📚

• Installation
• Quick Start
• API Overview
• Examples
  • Basic Counter Example
  • Listening for Errors
• Advanced Usage
  • Custom State Types
  • Middleware and Logging
• Contributing
• License

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Installation

Add quick_change to your pubspec.yaml:

dependencies:
  quick_change: ^1.0.0

Then run:

flutter pub get

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Quick Start 🚀

1. Define a QuickChangeController to manage your state.
2. Use QuickChangeBuilder to listen to state changes and update the UI.
3. Use .quickListen to respond to state changes outside of rebuilds.

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API Overview

• QuickStateController: Manages state changes and notifies listeners.
• States:
  • QuickInitial: Represents the initial state.
  • QuickLoading: Represents a loading state.
  • QuickData<T>: Holds data of type T.
  • QuickError: Represents an error state with a message.
• QuickStateBuilder: A widget that builds UI based on the controller’s state.
• .quickListen: An extension on widgets to listen to state changes without rebuilding.

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Examples

Basic Counter Example

Here’s how to create a simple counter using quick_state.

import 'package:quick_change/quick_change.dart';

class  CounterController extends QuickChangeController<int> {

incrementCounter(int cVal) {
     print(cVal);
int val = cVal+1;
  setData(val);
   }

   decrementCounter(int cVal) {
     int val = cVal-1;
     setData(val);
 }
}

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

void main() {
  GetIt.I.registerLazySingleton<CounterController>(() => CounterController());
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: CounterScreen(),
    );
  }
}

class CounterScreen extends StatefulWidget {
  const CounterScreen({super.key});

  @override
  CounterScreenState createState() => CounterScreenState();
}

class CounterScreenState extends State<CounterScreen> {
  @override
  void initState() {
    super.initState();
  }

  CounterController counterController = GetIt.I<CounterController>();
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Quick_State Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            QuickChangeBuilder<int>(
              controller: counterController,
              onLoading: (context) => const CircularProgressIndicator(),
              onData: (context, data) =>
                      Text('Counter: $data', style: const TextStyle(fontSize: 24)),
              onError: (context, message) => Text('Error: $message'),
            ),
            ElevatedButton(
              onPressed: () {
                final currentValue = counterController.currentData ?? 0;
                counterController.incrementCounter(currentValue);
              },
              child: const Text('Increment Counter'),
            ),
            ElevatedButton(
              onPressed: () {
                final currentValue = counterController.currentData ?? 0;
                counterController.decrementCounter(currentValue);
              },
              child: const Text('Decrement Counter'),
            ),
            ElevatedButton(
              onPressed: () {
                Navigator.push(context,
                        MaterialPageRoute(builder: (context) => PostsScreen()));
              },
              child: const Text('Api Page'),
            ),
            // Text(counterController.currentData.toString()),
          ],
        ).quickListen<int>(
          controller: counterController,
          listener: (context, state) {
            if (state is QuickData) {
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(
                  content: Text('Counter: ${state.data}'),
                  duration: const Duration(milliseconds: 400),
                ),
              );
            }
            if (state is QuickError) {
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(content: Text(state.message)),
              );
            }
          },
        ),
      ),
    );
  }
}

Listening for Errors

You can use .quickListen to display a Custom message such as SnackBar when an error occurs.

  // Listen for errors
 Widget.quickListen(
      controller: counterController,
      listener: (state) {
        if (state is QuickError) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text(state.message)),
          );
        }
      },
    );
}

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Advanced Usage

Custom State Types

Define custom states by extending QuickState.

class QuickCustomSuccess extends QuickState {
  final String message;
  QuickCustomSuccess(this.message);
}
Just use this in your controller for fluxing or emmiting a custom state 
quickFlux(QuickCustomSuccess("This is custom state "));

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Contributing 🤝

We welcome contributions! Please read our Contributing Guide for more details on how to get involved.

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License 📄

This project is licensed under the MIT License. See the LICENSE file for more details.

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Happy coding! 😊🎉 With quick_change & Farooq , managing Flutter state transitions has never been simpler.