Saverly

Saverly is a Dart library designed to simplify the process of saving and loading key-value pairs persistently in Flutter applications. It provides a reusable mixin to add JSON-based serialization and persistence capabilities to any class.

Features

• Persistent Storage: Save and load data effortlessly using JSON files backed by shared_preferences.

• Automatic File Name Handling: Each class gets a default file name based on its type.

• JSON Serialization: Convert objects to/from JSON seamlessly.

• Reactive State Management: Supports ValueNotifier for automatic save operations when values change.

• UI Integration: Works well with Flutter’s reactive widgets like ValueListenableBuilder.

How to Use

Step 1: Mix in Saverly

To use Saverly, mix it into your class and implement the required methods:

• toJson: Convert the class to a JSON Map.

• copyFromJson: Populate the class’s fields from a JSON Map.

Step 2: Use ValueNotifier for Reactive State Management

Declare your class properties as ValueNotifier to enable reactive state changes and automatic saving.

Example: Managing User Preferences

Here’s an example demonstrating how to use Saverly with ValueNotifier for automatic save operations:

Define the Class

import 'package:flutter/foundation.dart';
import 'package:saverly/saverly.dart';

class UserPreferences with Saverly {
  /// Use ValueNotifier for reactive updates
  late final ValueNotifier<String?> languageNotifier =
      ValueNotifier<String?>(null)..addListener(save);
  late final ValueNotifier<bool?> isDarkModeNotifier =
      ValueNotifier<bool?>(null)..addListener(save);

  UserPreferences() {
    load();
  }

  @override
  Map<String, dynamic> toJson() => {
        'language': languageNotifier.value,
        'isDarkMode': isDarkModeNotifier.value,
      };

  @override
  void copyFromJson(Map<String, dynamic> data) {
    // Update ValueNotifiers when data is loaded
    languageNotifier.value = data['language'] as String?;
    isDarkModeNotifier.value = data['isDarkMode'] as bool?;
  }
}

Use the Class

void main() async {
  final prefs = UserPreferences();

  

  print('Initial Preferences:');
  print('Language: ${prefs.languageNotifier.value}');
  print('Dark Mode: ${prefs.isDarkModeNotifier.value}');

  // Update preferences
  prefs.languageNotifier.value = 'en'; // Automatically saves
  prefs.isDarkModeNotifier.value = true; // Automatically saves

  print('Preferences updated and saved!');
}

File Name

The default file name for each class is derived from the class name in uppercase, followed by .json. For example:

• A class UserPreferences will have the file name USERPREFERENCES.json.

If you want to use a custom file name, override the fileName property in your class:

@override
String get fileName => 'custom_prefs.json';

UI Integration Example

import 'package:flutter/material.dart';

class SettingsScreen extends StatelessWidget {
  final UserPreferences prefs;

  SettingsScreen(this.prefs);

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        // Language Dropdown
        ValueListenableBuilder<String?>(
          valueListenable: prefs.languageNotifier,
          builder: (context, language, _) {
            return DropdownButton<String>(
              value: language,
              items: ['en', 'es', 'fr'].map((lang) {
                return DropdownMenuItem(value: lang, child: Text(lang));
              }).toList(),
              onChanged: (newLang) => prefs.languageNotifier.value = newLang,
            );
          },
        ),
        // Dark Mode Switch
        ValueListenableBuilder<bool?>(
          valueListenable: prefs.isDarkModeNotifier,
          builder: (context, isDarkMode, _) {
            return SwitchListTile(
              title: Text('Dark Mode'),
              value: isDarkMode ?? false,
              onChanged: (value) => prefs.isDarkModeNotifier.value = value,
            );
          },
        ),
      ],
    );
  }
}

Best Practices

1. Avoid Blocking the UI:

Since load and save are asynchronous, always use await to avoid blocking the UI.

2. Use Reactive Programming:

Bind ValueNotifier to widgets for real-time updates.

3. Secure Sensitive Data:

If you’re storing sensitive information, consider encrypting the JSON before saving it.

Contributions

We welcome contributions to improve Saverly! Feel free to submit issues or pull requests on the GitHub repository.

This README provides a complete overview of the library and its usage. Let me know if you’d like any further customizations!