flutter_apprun 0.8.1
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A lightweight, easy-to-use, event-driven state management system, highly inspired by AppRun JS
Flutter AppRun #
A lightweight, easy-to-use, event-driven state management system, highly inspired by AppRun JS.
Features #
- Use events to drive state changes, easy to understand.
- Use pure functions to update the state, easy to test state changes.
- The events also drive UI updates, no need to use
setState
. - The local events are scoped to the widget, no need to worry about the global events.
- The global events are used to communicate between widgets, no need to use
Provider
orBloc
. - Fully support asynchronous state changes.
Getting started #
Install it using pub:
flutter pub add flutter_apprun
And import the package:
import 'package:flutter_apprun/flutter_apprun.dart';
Usage #
Use AppRunWidget
in your widget tree.
AppRunWidget(
state: initialState,
update: update,
builder: (BuildContext context, state) {
return ... // widget tree biuld from the state
}
)
- The
state
is the initial state - The
update
is the collection of event handlers. - The
builder
is to display the state, which is called whenever the state changes. - Use
app.run
to trigger global events. - Use
AppRun.of(context).run
to trigger local events.
Example #
A counter page with two buttons to increment and decrement the counter.
// Define the initial state
int initialState = 0;
// Define the event handler collection in a map
int add(int state, int delta) => state + delta;
Map update = {
'@add': add, // global event
'+1': (state) => add(state, 1), // local event
'-1': (state) => add(state, -1), // local event
};
// Use the AppRunWidget in your widget tree
class HomePage extends StatelessWidget {
final String title;
const HomePage({super.key, required this.title});
@override
Widget build(BuildContext context) {
return AppRunWidget(
state: initialState,
update: update,
builder: (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: () => app.run('@add', -1), // global event
onPressed: () => AppRun.of(context).run('-1'), // local event
tooltip: 'Decrement',
child: const Icon(Icons.remove),
),
FloatingActionButton(
heroTag: 'plus',
// onPressed: () => app.run('@add', 1), // global event
onPressed: () => AppRun.of(context).run('+1'), // local event
tooltip: 'Increment',
child: const Icon(Icons.add),
),
],
),
);
},
);
}
}
License #
MIT License
Additional information #
Copyright (c) 2023, Yiyi Sun