Manage the state of your widgets

  State Management, Widgets

Imperative Flutter

Manage the state of your widgets using imperative programming concepts.

Setup

Intall imperative_flutter package in pubspec.yaml

dependencies:
  imperative_flutter: ^0.0.2

Then it’s just import in your code

import 'package:imperative_flutter/imperative_flutter.dart';

Usage

ImperativeProvider is responsible for storing and handling the references for ImperativeBuilder, it can be global scope when MaterialApp is his child or local scope when Scaffold is your child.

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ImperativeProvider(
      child: MaterialApp(
        title: 'Imperative Flutter Demo',
        home: MyHomePage(),
      ),
    );
  }
}

ImperativeBuilder is responsible for store the state of our widget and reconstructing it when that state is changed, note that the id must be unique for each ImperativeProvider Scope.

// Inside StatelessWidget

ImperativeBuilder<int>(
    id: 'count',
    initialData: 0,
    /* the builder method will be called every time the state changes,
    updating only the widget within the scope */
    builder: (context, snapshot) {
        return Container(
            height: 48,
            width: 48,
            color: Colors.pink,
            child: Center(
                child: Text(
                    '${snapshot.data}',
                    style: TextStyle(color: Colors.white),
                  ),
            ),
        );
    },
),

// ...

class Whatever extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // Get instance of ImperativeProvider
    final imperative = ImperativeProvider.of(context);

    return ElevatedButton.icon(
            onPressed: () {
                // Get current state of ImperativeBuilder where id equal 'count'
                final value = imperative.getState<int>('count');
                // Set state of ImperativeBuilder where id equal 'count' and rebuild
                imperative.setState('count', value + 1);
            },
            icon: Icon(Icons.add),
            label: Text('plus'),
    ),
  }

Download this widget source code at GitHub

https://github.com/JunioJsv/imperative-flutter