multi_value_listenable 0.0.1

A package that provides a MultiValueListenable class that allows you to listen to multiple ValueListenable, ValueNotifier objects at once.

MultiValueListenableBuilder

MultiValueListenableBuilder is a Flutter widget that listens to multiple ValueNotifiers and rebuilds its UI when any of them change. This is useful when you need to react to changes from multiple value notifiers and update the UI accordingly.

Features

• Listens to multiple ValueNotifiers at once.
• Automatically rebuilds the UI when any of the notifiers change.
• Provides a clean and simple API for handling multiple ValueNotifiers in your Flutter apps.

Installation

Add the following to your pubspec.yaml:

dependencies:
  multi_value_listenable: ^1.0.0

Then run:

flutter pub get

Usage

The MultiValueListenableBuilder widget takes in a list of ValueNotifiers and listens for changes. When any of the notifiers change, the builder function is called, allowing you to update the UI.

Example

import 'package:flutter/material.dart';
import 'package:multi_value_listenable/multi_value_listenable.dart';

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'Multi Value Listenable',
      home: MyHomePage(),
    );
  }
}

class NameController extends TextEditingController {}

class SurnameController extends TextEditingController {}

class MiddleNameController extends TextEditingController {}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late NameController _nameController;
  late SurnameController _surnameController;
  late MiddleNameController _middleNameController;

  @override
  void initState() {
    super.initState();
    _nameController = NameController();
    _surnameController = SurnameController();
    _middleNameController = MiddleNameController();
  }

  @override
  void dispose() {
    super.dispose();
    _nameController.dispose();
    _surnameController.dispose();
    _middleNameController.dispose();
  }

  void _callback() {}

  void _listen(ListValueNotifier values) {
    final name = values.get<NameController>();
    final surname = values.get<SurnameController>();
    final middleName = values.get<MiddleNameController>();

    final bool isAccess = name.text.isNotEmpty &&
        surname.text.isNotEmpty &&
        middleName.text.isNotEmpty;

    if (isAccess) {
      ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
        content: Text('Success'),
      ));
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SingleChildScrollView(
        child: Column(
          children: [
            TextField(
              controller: _nameController,
              decoration: const InputDecoration(
                labelText: 'Name',
              ),
            ),
            TextField(
              controller: _surnameController,
              decoration: const InputDecoration(
                labelText: 'Surname',
              ),
            ),
            TextField(
              controller: _middleNameController,
              decoration: const InputDecoration(
                labelText: 'Middle Name',
              ),
            ),
            const SizedBox(
              height: 12,
            ),
            MultiValueListenableBuilder(
              listenable: _listen,
              valuesListenable: [
                _nameController,
                _surnameController,
                _middleNameController,
              ],
              builder: (context, values, child) {
                final name = values.get<NameController>();
                final surname = values.get<SurnameController>();
                final middleName = values.get<MiddleNameController>();

                final bool isDisable = name.text.isEmpty ||
                    surname.text.isEmpty ||
                    middleName.text.isEmpty;

                return ElevatedButton(
                  onPressed: isDisable ? null : _callback,
                  child: const Text('Send'),
                );
              },
            ),
          ],
        ),
      ),
    );
  }
}

In this example:

• We have three TextEditingController instances for Name, Surname, and Middle Name.
• The MultiValueListenableBuilder listens to these controllers and updates the button's state based on whether the fields are filled in.
• The listenable callback checks if all fields are non-empty and shows a success message.

Parameters

• valuesListenable: A list of ValueNotifiers to listen to. The builder function will be called whenever any of the notifiers change.
• builder: The function that builds the widget tree. It is called with the current BuildContext, the list of values from the notifiers, and an optional child widget.
• listenable (optional): A function that can be triggered when the notifiers change.
• child (optional): A widget that is passed to the builder and can be used to optimize performance by not rebuilding static content.

License

This package is licensed under the MIT License. See the LICENSE file for more information.

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