stash_shared_preferences

A stash storage extension for shared_preferences

Overview

This storage extension for stash provides a shared_preferences based storage.

Getting Started

Add this to your pubspec.yaml (or create it) replacing x.x.x with the latest version of stash_shared_preferences:

dependencies:
    stash_shared_preferences: ^x.x.x

Run the following command to install dependencies:

flutter pub get

Finally, to start developing import the library:

import 'package:stash/stash_api.dart';
import 'package:stash_shared_preferences/stash_shared_preferences.dart';

Usage

The example bellow creates a vault with a shared_preferences storage backend. In this rather simple example the serialization and deserialization of the object is coded by hand but it's more usual to rely on libraries like json_serializable.

import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:stash/stash_api.dart';
import 'package:stash_shared_preferences/stash_shared_preferences.dart';

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

class Counter {
  final int value;
  final DateTime updateTime;

  Counter({required this.value, required this.updateTime});

  /// Creates a [Counter] from json map
  factory Counter.fromJson(Map<String, dynamic> json) => Counter(
      value: json['value'] as int,
      updateTime: DateTime.parse(json['timestamp'] as String));

  /// Creates a json map from a [Task]
  Map<String, dynamic> toJson() => <String, dynamic>{
        'value': value,
        'timestamp': updateTime.toIso8601String()
      };
}

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Stash Shared Preferences Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const SharedPreferencesDemo(),
    );
  }
}

class SharedPreferencesDemo extends StatefulWidget {
  const SharedPreferencesDemo({Key? key}) : super(key: key);

  @override
  SharedPreferencesDemoState createState() => SharedPreferencesDemoState();
}

class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
  final Future<Vault<Counter>> _vault = newSharedPreferencesVaultStore().then(
      (store) => store.vault<Counter>(
          name: 'vault', fromEncodable: (json) => Counter.fromJson(json)));
  late Future<Counter> _counter;

  Future<Counter> _getCounter([Vault<Counter>? vault]) {
    final v = vault == null ? _vault : Future.value(vault);

    return v.then((vault) => vault.get('counter')).then(
        (counter) => counter ?? Counter(value: 0, updateTime: DateTime.now()));
  }

  Future<void> _incrementCounter() async {
    final Vault<Counter> vault = await _vault;
    final Counter currentCounter = await _getCounter(vault);

    setState(() {
      final newCounter =
          Counter(value: currentCounter.value + 1, updateTime: DateTime.now());
      _counter = vault.put('counter', newCounter).then((value) => newCounter);
    });
  }

  @override
  void initState() {
    super.initState();
    _counter = _getCounter();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('SharedPreferences Demo'),
      ),
      body: Center(
          child: FutureBuilder<Counter>(
              future: _counter,
              builder: (BuildContext context, AsyncSnapshot<Counter> snapshot) {
                switch (snapshot.connectionState) {
                  case ConnectionState.none:
                  case ConnectionState.waiting:
                    return const CircularProgressIndicator();
                  case ConnectionState.active:
                  case ConnectionState.done:
                    if (snapshot.hasError) {
                      return Text('Error: ${snapshot.error}');
                    } else {
                      final count = snapshot.data?.value ?? 0;
                      final updateTime = snapshot.data?.updateTime;
                      final lastPressed = updateTime != null
                          ? ' (last pressed on ${DateFormat('dd-MM-yyyy HH:mm:ss').format(updateTime)})'
                          : '';
                      return Text(
                        'Button tapped $count time${count == 1 ? '' : 's'}.\n\n'
                        'This should persist across restarts$lastPressed.',
                      );
                    }
                }
              })),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}

Additional Features

Please take a look at the documentation of stash to gather additional information and to explore the full range of capabilities of the stash library

Features and Bugs

Please file feature requests and bugs at the issue tracker.

License

This project is licensed under the MIT License - see the LICENSE file for details