context_ref

Description:

context ref

context_ref #





A more convenient InheritedWidget alternative.
See context_plus for the ultimate convenience.
Features #

Ref<T> - a reference to a value of type T bound to a context or multiple contexts.

.bind(context, () => Value()) - create and bind value to a context. Automatically dispose() the value upon context disposal.
.bindLazy(context, () => Value()) - same as .bind(), but the value is created only when it's first accessed.
.bindValue(context, value) - bind an already created value to a context. The value is not disposed automatically.
.of(context) - get the value bound to the context or its nearest ancestor.



Getting started #
flutter pub add context_ref
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Wrap your app in a ContextRef.root widget.
ContextRef.root(
child: MaterialApp(...),
);
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(Optional) Wrap default error handlers with ContextRef.errorWidgetBuilder() and ContextRef.onError() to get better hot reload related error messages.
void main() {
ErrorWidget.builder = ContextRef.errorWidgetBuilder(ErrorWidget.builder);
FlutterError.onError = ContextRef.onError(FlutterError.onError);
}
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Usage #
Initialize and propagate a value down the widget tree:
final _state = Ref<_State>();

class Example extends StatelessWidget {
const Example({super.key});

@override
Widget build(BuildContext context) {
// No need to specify the `dispose` callback by hand if the _State is
// disposable via the `dispose` method.
//
// The `_State` will be created right await and disposed when the widget
// is removed from the widget tree.
//
// Use `bindLazy` if you want to create the value only when it's first accessed.
_state.bind(context, () => _State());
return const _Child();
}
}

class _Child extends StatelessWidget {
const _Child();

@override
Widget build(BuildContext context) {
final state = _state.of(context);
...
}
}
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Provide an already-initialized value down the tree:
final _params = Ref<Params>();

class Example extends StatelessWidget {
const Example({
super.key,
required this.params,
});

final Params params;

@override
Widget build(BuildContext context) {
// Whenever the `params` value change, the `_Child` widget will get rebuilt.
// Values provided via `bindValue` are not disposed automatically.
_params.bindValue(context, params);
return const _Child();
}
}

class _Child extends StatelessWidget {
const _Child();

@override
Widget build(BuildContext context) {
final params = _params.of(context);
...
}
}
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For more examples, see the example.