mu_state #

A minimal state solution based on my Pragmatic state handling in Flutter Medium article .

Features #

A set of classes built on ValueNotifier and ValueListenableBuilder.

• MuEvent<T> - the base class for our 3 state object
• MuEventData<T> - the data state of type T
• MuEventError<T> - the error state of type T
• MuEventLoading<T> - the loading state of type T
• MuState<T> - a ValueNotifier of type MuEvent<T>
• MuBuilder<T> - a ValueListenableBuilder of type MuEvent<T>
• MuMultiBuilder - listen to a list of MuState's and get notified with a list of MuEvent's

How To #

Declare state as a global final MuState<T> variable and pass it an initial MuEvent type, e.g. a MuEventLoading or a MuEventData<T>.

Alternatively extend MuState and implement the necessary methods.

Listen to MuState changes using MuBuilder.

Listen to multiple MuState objects using MuMultiBuilder and handle the list of MuEvent's on changes.

Example #

In test_state.dart:

import 'package:mu_state/mu_state.dart';

class CounterState extends MuState<int> {
  CounterState(MuEvent initValue) : super(initValue);

  void increment() {
    value = MuEventData((value as MuEventData<int>).data + 1);
  }
}

final counterState = CounterState(const MuEventData(0));

In main.dart:

Scaffold(
  body: Center(
    child: MuBuilder(
      state: counterState,
      builder: (context, event, child) {
        return switch (event) {
          MuEventLoading() => const CircularProgressIndicator(),
          MuEventError(error: Object error) => Text('Error: $error'),
          MuEventData(data: int value) => Text('$value')
        };
      },
    ),
  ),
),

Also see Example.