Empire<T extends EmpireViewModel> class Null safety

Used to provide shared state and functions across specific scopes of your application, or the entire application itself.

The viewModel should contain any state or functionality that is required by one or more child widgets. See viewModelOf for information on accessing the view model.

onAppStateChanged is required and should return a unique String value each time it is called. This is used to determine whether the EmpireApp inherited widget needs to be updated, therefore updating all it's child widgets. Consider using the Uuid package.

If you are implementing your own unique string mechanism, know that if it generates the same value twice in a row, your second change will not be reflected in the application until a new, unique value is generated.

Example Using Uuid

import 'package:uuid/uuid.dart';

Empire(
 myViewModel,
 child: HomePage(),
 onAppStateChanged: () => Uuid().v1(),
)

Nested / Scoped Empires

Empire(
 MyApplicationViewModel(),
 onAppStateChanged: () => Uuid().v1(),
 child: MaterialApp(
  title: 'My App',
  home: Scaffold(
    backgroundColor: Empire.viewModelOf<MyApplicationViewModel>().backgroundColor.value,
    child: Empire(
      MyHomePageViewModel(),
      onAppStateChanged: () => Uuid().v1(),
      child: Builder(builder: (innerContext){
        return Center(
          child: Text(${Empire.viewModelOf<MyHomePageViewModel>().title.value})
        );
      }),
    )
  )
 )
)