NotifierBuilder

Builds a subtree when notifier publishes a change.

Import: package:fleury/fleury.dart, or package:fleury/fleury_core.dart in browser code.

Usage

NotifierBuilder(
  notifier: cart,
  builder: (context, cart) => Text('Items: ${cart.itemCount}'),
)

Details

The builder receives the original, typed notifier and a context belonging to this widget. Additional context.listen or context.scope calls inside the builder also rebuild this widget, rather than its parent.

Subscriptions follow the sources used by each build and are removed when this widget unmounts. The source remains owned by its caller and is never disposed by this widget. Any Listenable is supported, including Notifier, ValueNotifier, animations, and custom subscription sources.

Constructors

`NotifierBuilder()`

Parameter	Type	Default	Description
`notifier:`	`T`	required	The model or other subscription source to observe.
`builder:`	`Widget Function(BuildContext context, T notifier)`	required	Builds from the current state of `notifier` whenever it notifies.

Source

NotifierBuilder is defined in packages/fleury/lib/src/widgets/notifier_builder.dart.

Category: State & async · All widgets

Example · editable

class CartView extends StatelessWidget {
  const CartView({super.key, required this.cart});

  final Cart cart;

  @override
  Widget build(BuildContext context) => NotifierBuilder(
    notifier: cart,
    builder: (context, cart) => Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Items: ${cart.itemCount}'),
        Button(text: 'Add item', onPressed: cart.addItem),
      ],
    ),
  );
}

class CartContextView extends StatelessWidget {
  const CartContextView({super.key, required this.cart});

  final Cart cart;

  @override
  Widget build(BuildContext context) {
    final model = context.listen(cart);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Items: ${model.itemCount}'),
        Button(text: 'Add item', onPressed: model.addItem),
      ],
    );
  }
}

class _CartDemoState extends State<CartDemo> {
  final cart = Cart();

  @override
  void dispose() {
    cart.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) => Column(
    crossAxisAlignment: CrossAxisAlignment.start,
    children: [
      const Text('NotifierBuilder', style: CellStyle(bold: true)),
      CartView(cart: cart),
      const SizedBox(height: 1),
      const Text('context.listen', style: CellStyle(bold: true)),
      CartContextView(cart: cart),
    ],
  );
}

Live preview

Live · interactive

click & type to interact ⓘ how this demo runs