notification_builder

? A widget that builds using notifications dispatched via the build context.

About

Notifications — is a tool Flutter uses to pass the data higher in the widget tree hierarchy. Somewhere in depth of your widget tree you can fire a notification and it will go up, like a bubble. And on top, you can catch it using a NotificationBuilder to build your UI.

The problem

Imagine the following widget tree:

MyWidget(
  color: // I want this to be changed once the button below is clicked!
  child: const SomeChild(
    child: AnotherChild(
      // More and more widgets...
      child: ChildWithTheButton(),
    ),
  ),  
);

class ChildWithTheButton extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return TextButton(
      title: 'Change colour',
      onPressed: // Here! I want the colour to be changed on this button pressed!
    );
  }
}

You could either pass something like a ChangeNotifier<Color>, or pass a callback function to set the state, or even use an InheritedWidget. Another option is to use a NotificationListener.

The solution

to check out the full example.

Result

If you don’t want certain notification to trigger rebuilds…

Then you can use the buildWhen parameter!

buildWhen: (notification) {
  // Now if the passed notification will have a red color it will be ignored!
  return notification.color != Colors.red,
}

Getting started

pub

Add the package to pubspec.yaml:

dependencies:
  notification_builder:

Import

Add the dependency to your file:

import 'package:notification_builder/notification_builder.dart';