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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// ignore_for_file: public_member_api_docs
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'SharedPreferences Demo',
home: SharedPreferencesDemo(),
);
}
}
class SharedPreferencesDemo extends StatefulWidget {
SharedPreferencesDemo({Key key}) : super(key: key);
@override
SharedPreferencesDemoState createState() => SharedPreferencesDemoState();
}
class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
Future<int> _counter;
Future<void> _incrementCounter() async {
final SharedPreferences prefs = await _prefs;
final int counter = (prefs.getInt('counter') ?? 0) + 1;
setState(() {
_counter = prefs.setInt("counter", counter).then((bool success) {
return counter;
});
});
}
@override
void initState() {
super.initState();
_counter = _prefs.then((SharedPreferences prefs) {
return (prefs.getInt('counter') ?? 0);
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("SharedPreferences Demo"),
),
body: Center(
child: FutureBuilder<int>(
future: _counter,
builder: (BuildContext context, AsyncSnapshot<int> snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.waiting:
return const CircularProgressIndicator();
default:
if (snapshot.hasError) {
return Text('Error: ${snapshot.error}');
} else {
return Text(
'Button tapped ${snapshot.data} time${snapshot.data == 1 ? '' : 's'}.\n\n'
'This should persist across restarts.',
);
}
}
})),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
),
);
}
}
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