Flutter AppRun

A lightweight, easy-to-use, event-driven state management system, highly inspired by AppRun JS.

Features

• Use events to drive state changes.
• Use pure functions to update the state, easy to test state changes.
• The events also drive UI updates, no need to use setState to update the state.
• Global event bus, you can use events to communicate between widgets.
• Fully support asynchronous state changes.

Getting started

Install it using pub:

dart pub add flutter_apprun

And import the package:

import 'package:flutter_apprun/flutter_apprun.dart';

Usage

Extend the AppRunWidget class to create your widget:

// Define the initial state
int initialState = 0;

// Define the update map
int add(int state, int delta) => state + delta;
Map update = {
  'add': add,
  '+1': (state) => add(state, 1),
  '-1': (state) => add(state, -1),
};

// Extend the AppRunWidget class to create your widget
class HomePage extends AppRunWidget {
  final String title;

  // Pass the initial state and update map to the super class
  HomePage({super.key, required this.title})
      : super(state: initialState, update: update);

  // Display the state
  @override
  Widget build(BuildContext context, state) {
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              '$state',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: Column(
        mainAxisAlignment: MainAxisAlignment.end,
        children: [
          FloatingActionButton(
            heroTag: 'minus',
            // onPressed: () => run('add', -1),
            onPressed: () => run('-1'),
            tooltip: 'Decrement',
            child: const Icon(Icons.remove),
          ),
          FloatingActionButton(
            heroTag: 'plus',
            // onPressed: () => run('add', 1),
            onPressed: () => run('+1'),
            tooltip: 'Increment',
            child: const Icon(Icons.add),
          ),
        ],
      ),
    );
  }
}

License

MIT License

Additional information

• AppRun JS
• AppRun Architecture

Copyright (c) 2023, Yiyi Sun