local_value 1.1.1 local_value: ^1.1.1 copied to clipboard
A simple abstraction to persist data in the local file system.
import 'package:flutter/material.dart';
import 'package:local_value/local_value.dart';
class CounterObj {
int value;
CounterObj(this.value);
}
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
final counterStorage = LocalSingleton<int>(id: 'counter');
MyHomePage({Key? key}) : super(key: key);
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Local Data Manager Demo'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
floatingActionButton: Builder(
builder: (context) => Row(
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
FloatingActionButton(
onPressed: () => widget.counterStorage.read().then((value) {
if (value == null) {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('no local data saved')));
return;
}
setState(() {
_counter = value;
});
}),
backgroundColor: Colors.orange,
child: const Icon(Icons.replay),
),
FloatingActionButton(
onPressed: () =>
widget.counterStorage.write(_counter).then((_) {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(content: Text('saved!')));
}),
backgroundColor: Colors.green,
child: const Icon(Icons.save),
),
FloatingActionButton(
onPressed: _incrementCounter,
child: const Icon(Icons.add),
),
],
)),
);
}
}