import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
void main() {
runApp(
MaterialApp(
title: 'Reading and Writing Files',
home: FlutterDemo(storage: CounterStorage()),
),
);
}
class CounterStorage {
Future<String> get _localPath async {
final directory = await getApplicationDocumentsDirectory();
return directory.path;
}
Future<File> get _localFile async {
final path = await _localPath;
return File('$path/counter.txt');
}
Future<int> readCounter() async {
try {
final file = await _localFile;
final contents = await file.readAsString();
return int.parse(contents);
} catch (e) {
return 0;
}
}
Future<File> writeCounter(int counter) async {
final file = await _localFile;
return file.writeAsString('$counter');
}
}
class FlutterDemo extends StatefulWidget {
const FlutterDemo({super.key, required this.storage});
final CounterStorage storage;
@override
State<FlutterDemo> createState() => _FlutterDemoState();
}
class _FlutterDemoState extends State<FlutterDemo> {
int _counter = 0;
@override
void initState() {
super.initState();
widget.storage.readCounter().then((value) {
setState(() {
_counter = value;
});
});
}
Future<File> _incrementCounter() {
setState(() {
_counter++;
});
return widget.storage.writeCounter(_counter);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Reading and Writing Files'),
),
body: Center(
child: Text(
'Button tapped $_counter time${_counter == 1 ? '' : 's'}.',
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
),
);
}
}