flutter_arbor
Flutter integration for arbor – a modular and compile-time safe DI for Flutter without fragility and magic.
Index
About
Read more about arbor before using this package. This package is a Flutter integration for arbor and should be used in pair.
flutter_arbor provides a widget that effectively propagates dependency nodes using InheritedWidgets to the Element tree.
Motivation
As arbor is a pure Dart package, it can be used in any Dart project.
However, it is not a Flutter package and does not provide any Flutter-specific features – this is where flutter_arbor comes in, providing a way to effectively propagate dependency nodes using InheritedWidgets to the Element tree, integrating the package with Flutter.
Install
Add flutter_arbor to your pubspec.yaml file:
dependencies:
flutter_arbor: "current version"
Or do it via CLI:
$ flutter pub add flutter_arbor
Usage
flutter_arbor can be used in two ways: to provide an initial root Tree instance or to provide a Tree instance for a stateful subtree, that is, a ChildNode created through a child method.
An example dependencies structure can be described as follows:
class AppDependencies extends BaseTree<AppDependencies> {
ObjectFactory<ExampleChild> get exampleChild => child(ExampleChild.new);
}
class ExampleChild extends BaseChildNode<ExampleChild, AppDependencies> {
ExampleChild(super.parent);
}
This structure consists of two nodes: AppDependencies and ExampleChild. AppDependencies is a root node, and ExampleChild is a child node of AppDependencies.
Root node
To provide a root Tree instance, a default unnamed constructor of NodeScope should be used:
NodeScope<AppDependencies>(
create: (context) => AppDependencies(),
child: child,
);
Placing this widget in the Widgets structure will effectively propagate AppDependencies to all the Elements below it, which can be accessed through NodeScope.of<N>(context, listen: listen).
Child node
To provide a Tree instance for a stateful subtree, a named constructor child of NodeScope should be used:
NodeScope.child(
create: (context, find) => find<AppDependencies>().exampleChild,
child: child,
);
The named constructor offers a shortcut to finding a parent node and creating a child node from it and lifts the return type of create to a thunk - ObjectFactory<N>/N Function().