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read and write files in dart

Frail Finch answered on August 27, 2022 Popularity 5/10 Helpfulness 3/10

answer read and write files in dart

read and write files in dart

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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;

      // Read the file
      final contents = await file.readAsString();

      return int.parse(contents);
    } catch (e) {
      // If encountering an error, return 0
      return 0;
    }
  }

  Future<File> writeCounter(int counter) async {
    final file = await _localFile;

    // Write the file
    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++;
    });

    // Write the variable as a string to the file.
    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),
      ),
    );
  }
}

Popularity 5/10 Helpfulness 3/10 Language whatever

Source: docs.flutter.dev

Tags: dart whatever

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Contributed on Aug 27 2022

Frail Finch

0 Answers Avg Quality 2/10

read and write files in dart

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