Description

Flutter StateManager is a simple state management and IoC library for Dart and Flutter.

Why use it?

• Objects are grouped in single place (container). Enough of getting a crowded context tree when you have many controllers/repos/etc... (like Provider does!)
• Objects are retrieved using an InheritedWidget. That means objects will reside where they should be: in the Context Tree (not in limbo!)
• The object container is built on a Map. So it's lightning fast!

Usage

Place the StateManMain class on the top of the MaterialApp and use the serviceContainerInitializer property to create the StateManServiceContainer which will contain all the objects you will access later.

You can register any object constructor and use container.resolve<T>() to retrieve any other instance of the type T from the container.

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return StateManMain(
      serviceContainerInitializer: () => StateManServiceContainer()
        ..register((container) => CounterRepository1())
        ..register((container) => CounterRepository2())
        ..register((container) => CounterRepository3())
        ..register((container) => CounterStore1(container.resolve<CounterRepository1>()))
        ..register((container) => CounterStore2(container.resolve<CounterRepository2>()))
        ..register((container) => CounterStore3(container.resolve<CounterRepository3>()))
        ..register((container) => CounterStoreTotal([
          container.resolve<CounterStore1>(),
          container.resolve<CounterStore2>(),
          container.resolve<CounterStore3>(),
        ])),
      child: MaterialApp(
        theme: ThemeData(primarySwatch: Colors.blue),
        home: const CountersPage(),
      ),
    );
  }
}

To be notified when any Listenable object changes in your container use StateManObserver<T> (where T extends Listenable). Every time the Listenable object is changed, the StateManObserver will rebuild the widget tree by calling the builder(Context context, T yourListenableObject, Widget yourChildWidget) function.

You can also retrieve any object from the container using StateManStorage.retrieve<T>(context) or the container itself using StateManStorage.container(context).

class CountersPage extends StatelessWidget {
  const CountersPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("flutter_stateman")),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.start,
          children: <Widget>[
            const Spacer(),
            StateManObserver<CounterStore1>(builder: (context, counterStore1, child) {
              return CounterWidget(store: counterStore1);
            }),
            StateManObserver<CounterStore2>(builder: (context, counterStore2, child) {
              return CounterWidget(store: counterStore2);
            }),
            StateManObserver<CounterStore3>(builder: (context, counterStore3, child) {
              return CounterWidget(store: counterStore3);
            }),
            const Spacer(),
            StateManObserver<CounterStoreTotal>(builder: (context, counterStoreTotal, child) {
              return Text("Total: ${counterStoreTotal.value}");
            }),
            const Spacer(),
            FloatingActionButton(
              onPressed: () {
                StateManStorage.retrieve<CounterStoreTotal>(context).reset();
              },
              backgroundColor: Colors.purpleAccent,
              child: const Icon(Icons.clear),
            ),
            const Spacer(),
          ],
        ),
      ),
    );
  }
}