flutter_widget_binder 0.0.1+2

A Flutter package for efficient state management with notifiers, async states, debouncing, undo/redo, and multiple state grouping.

Flutter Widget Binder

flutter_widget_binder is a Flutter package designed for managing application states efficiently. The package provides various state management solutions, including simple state notifiers, asynchronous state notifiers, debounce functionality, undo/redo capabilities, and multiple state grouping. These tools help manage the state of your application in a modular and scalable way.

Features

• State Notifiers: Simple state management that allows you to track and update states.
• Async State Notifiers: Manage asynchronous states and notify listeners on changes.
• Debouncing State Notifier: A state notifier that debounces state changes, useful for managing user inputs like search fields.
• Undoable State Notifier: Supports undo and redo operations, ideal for applications that require state history tracking.
• Multiple State Notifiers: Combines multiple state notifiers into one, emitting a combined stream.

Installation

Add the following dependency to your pubspec.yaml file:

Then, run the following command to install the package: flutter pub get

Usage AppState Singleton The AppState class provides a global, singleton instance for managing shared application state.

class AppState {
  static final AppState _instance = AppState._internal();

  factory AppState() => _instance;

  final StateNotifier<bool> sharedCheckerNotifier = StateNotifier<bool>(false);

  AppState._internal();
}

StateNotifier

StateNotifier is a basic state manager that allows state updates and listeners.

StateNotifier<int> counter = StateNotifier<int>(0);

counter.stream.listen((value) {
  print(value); // Prints state updates
});

counter.setValue(1); // Updates the state to 1

AsyncStateNotifier

AsyncStateNotifier allows handling asynchronous state updates, such as fetching data from an API.

AsyncStateNotifier<String> asyncStateNotifier = AsyncStateNotifier<String>("Initial Data");

asyncStateNotifier.updateAsync((currentState) async {
  await Future.delayed(Duration(seconds: 2));
  return "Updated Data";
});

DebounceStateNotifier

DebounceStateNotifier helps in managing state changes with debouncing functionality.

DebounceStateNotifier<String> searchQuery = DebounceStateNotifier<String>("");

searchQuery.update("new query", debounceDuration: Duration(milliseconds: 500));

UndoableStateNotifier

UndoableStateNotifier provides a mechanism to go back and forth in the state history, supporting undo and redo operations.

UndoableStateNotifier<int> undoableCounter = UndoableStateNotifier<int>(0);

undoableCounter.update(1); // Adds 1 to history
undoableCounter.update(2); // Adds 2 to history

undoableCounter.undo(); // Reverts back to 1
undoableCounter.redo(); // Moves forward to 2

MultipleStatesNotifier

MultipleStatesNotifier combines multiple state notifiers into a single stream, emitting a combined value when any of the states change.

StateNotifier<int> counter1 = StateNotifier<int>(0);
StateNotifier<String> counter2 = StateNotifier<String>("A");

MultipleStatesNotifier<dynamic> combinedState = MultipleStatesNotifier([counter1, counter2]);

combinedState.stream.listen((values) {
  print(values); // Prints the updated list of all states
});

API

BaseStateNotifier This is an abstract class defining the common interface for state management classes:

• value: Returns the current state value.
• stream: A stream that emits the state when it changes.
• dispose(): Cleans up resources when the state notifier is no longer needed.

StateNotifier A simple state notifier class:

• setValue(T newValue): Updates the state and notifies listeners.
• dispose(): Releases resources by closing the stream.

AsyncStateNotifier An async version of the state notifier that handles asynchronous operations:

• updateAsync(Future<T> Function(T current)): Updates the state asynchronously and notifies listeners.
• dispose(): Releases resources by closing the stream.

DebounceStateNotifier A state notifier with debounce functionality:

• update(T newValue, {Duration debounceDuration}): Updates the state after a debounce period.
• dispose(): Releases resources by closing the stream.

UndoableStateNotifier A state notifier with undo and redo functionality:

• update(T newValue): Updates the state and stores it in history.
• undo(): Reverts the state to the previous value.
• redo(): Moves the state forward to the next value.
• dispose(): Releases resources by closing the stream.

MultipleStatesNotifier A state notifier that manages multiple state notifiers:

• values: Returns a list of the current values of all managed state notifiers.
• stream: A stream that emits a list of values when any of the states change.
• dispose(): Releases resources by closing the stream.

Widget Binder - Flutter State Management

WidgetBinder is a widget designed to connect and manage state with child widgets in a Flutter application. It ensures that child widgets are rebuilt when the state changes, without the need to rebuild the entire widget tree.

Purpose:

• Ensure that child widgets are always updated with the latest state from a BaseStateNotifier.
• Provide an efficient and straightforward way to listen for state changes and update the UI accordingly.

How It Works:

WidgetBinder works by using a StreamBuilder to listen to the stream of changes from a BaseStateNotifier<T>. Whenever the state changes, the builder function is called to rebuild the widget with the new state.

Key Components:

• state: An object that extends BaseStateNotifier<T>, responsible for managing the state and emitting changes.
• builder: A function that takes the BuildContext and the current state value (T), and returns a widget. This function is invoked every time the state changes.

Example

final counterNotifier = StateNotifier<int>(0);

Widget build(BuildContext context) {
  return WidgetBinder<int>(
    state: counterNotifier,
    builder: (context, value) {
      return Text('Current value: $value');
    },
  );
}

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