widject_container

Description:

widject container

WidjectContainer #
Dependency Injection package for Flutter
Simple DI package to help structure your Flutter application in loosely coupled components. Inspired by VContainer.
Features #

Explicit constructor injection within scopes.

No use of reflection/mirrors.


Nested scope support to isolate dependencies by widget type.
Async initialization of scoped dependencies.

Installation #
Add the package with the command: flutter pub add widject_container or adding widject_container to your project's pubspec.yaml dependencies.
Basic Usage #
Create a scope connected to a widget and register the required types. The type references are automatically resolved when requested within the scope.
class AppScope extends Scope<AppWidget> {
AppScope(): super(null);

@override
void configure(ContainerRegister register) {
register.add((r) => HelloWorldProvider(), Lifetime.transient).as<MessageProvider>();
register.addWidget((r, key, _) => AppWidget(r.get(), key: key));
}
}
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Where classes are:
abstract class MessageProvider {
String getMessage();
}
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class HelloWorldProvider implements MessageProvider {
@override
String getMessage()
=> "Hello world!";
}
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class AppWidget extends StatelessWidget {
final MessageProvider _messageProvider;

const AppWidget(this._messageProvider, {super.key});

@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'WidjectContainer Demo',
home: Scaffold(
body: Text(_messageProvider.getMessage())
)
);
}
}
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Example of scope usage in main function is:
void main() {
var app = AppScope().getWidget();
runApp(app);
}
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Widget Provider #
Use WidgetProvider to instantiate widget types that have been registered within a scope. Dependencies are resolved and explicitly injected, as defined in the scope registration.
Example of registration:
class AppScope extends Scope<AppWidget> {
...

@override
void configure(ContainerRegister register) {
...
register.addWidget((r, key, _) => NewWidget(r.get(), args, key: key));
}
}
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Example of usage through WidgetProvider:
class AppWidget extends StatelessWidget {
final MessageProvider _messageProvider;
final WidgetProvider _widgetProvider;

const AppWidget(this._messageProvider, this._widgetProvider, {super.key});

@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'WidjectContainer Demo',
home: Scaffold(
body: _widgetProvider.getWidget<NewWidget>())
)
);
}
}
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Nested Scopes #
Connect the instantiation of a widget to a new scope, registering types and inheriting references from ancestor scopes.
This can be useful when creating a new screen that requires a whole new set of dependencies.
class ScreenScope extends Scope<ScreenWidget>{
ScreenScope(super.parentContainer);

@override
void configure(ContainerRegister register) {
register.addWidget((r, key, args) => ScreenWidget(...));
}
}
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Where the scoped widget binding in the parent scope is:
class AppScope extends Scope<AppWidget> {
...

@override
void configure(ContainerRegister register) {
...
register.addScopedWidget((r, key, _) => ScreenScope(r));
}
}
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Example of usage through WidgetProvider:
class AppWidget extends StatelessWidget {
final MessageProvider _messageProvider;
final WidgetProvider _widgetProvider;

const AppWidget(this._messageProvider, this._widgetProvider, {super.key});

@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'WidjectContainer Demo',
home: Scaffold(
body: TextButton(
onPressed: () => _openChildWidget(context),
child: Text(_messageProvider.getMessage()))));
}

_openChildWidget(BuildContext context) {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => _widgetProvider.getWidget<ScreenWidget>()));
}
}
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Credits #
WidjectContainer is inspired by:

VContainer.

Author #
Claudio Mazza
License #
MIT