obsidian-kingdom-8183

readme.md

obsidian-kingdom-8183

Created with <3 with dartpad.dev.

main.dart

import 'dart:convert';
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(
      home: Scaffold(
        appBar: AppBar(
          title: Text('SharedPreferences Demo'),
        ),
        body: MyDataWidget(),
      ),
    );
  }
}

class MyDataWidget extends StatefulWidget {
  @override
  _MyDataWidgetState createState() => _MyDataWidgetState();
}

class _MyDataWidgetState extends State<MyDataWidget> {
  MyData? _data;

  @override
  void initState() {
    super.initState();
    _loadData();
  }

  Future<void> _loadData() async {
    MyData? loadedData = await MyData.readInstance();
    if (loadedData != null) {
      setState(() {
        _data = loadedData;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: _data == null
          ? CircularProgressIndicator()
          : Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Text('Name: ${_data!.name}'),
                Text('Age: ${_data!.age}'),
              ],
            ),
    );
  }
}

// MyData 클래스는 이전 답변에서 제공한 것과 동일합니다.
class MyData {
  String name;
  int age;

  MyData({required this.name, required this.age});

  String toJson() => json.encode({'name': name, 'age': age});

  factory MyData.fromJson(String str) {
    final jsonData = json.decode(str);
    return MyData(name: jsonData['name'], age: jsonData['age']);
  }

  static Future<MyData?> readInstance() async {
    final prefs = await SharedPreferences.getInstance();
    final jsonString = prefs.getString('myData');

    if (jsonString == null) {
      return null;
    }

    return MyData.fromJson(jsonString);
  }

  Future<void> saveInstance() async {
    final prefs = await SharedPreferences.getInstance();
    prefs.setString('myData', toJson());
  }
}