How do I save data after closing the Flutter app?

Question

I try to create an App, where you can simply add a new TODO. My problem is that after a added a new TODO, and than close my App, my TODO-List is empty. What is the best way to save data in the App? Are there any simple solutions for that?

Answer 1

Just check out this sample todo list code i have created.

import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Container(
          child: TODOApp(),
        ),
      ),
    );
  }
}

class TODOApp extends StatefulWidget {
  TODOApp({Key key}) : super(key: key);

  @override
  _TODOAppState createState() => _TODOAppState();
}

class _TODOAppState extends State<TODOApp> {
  TextEditingController _todoController = TextEditingController();
  List<String> todoList = List();
  bool _isLoading = false;

  _saveList(list) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();

    prefs.setStringList("key", list);

    return true;
  }

  _getSavedList() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    if (prefs.getStringList("key") != null)
      todoList = prefs.getStringList("key");
    setState(() {});
  }

  @override
  void initState() {
   
    super.initState();
    setState(() {
      _isLoading = true;
    });
    _getSavedList();

    setState(() {
      _isLoading = false;
    });
  }

  Future<bool> _onWillPop() async {
    return (await showDialog(
          context: context,
          builder: (context) => new AlertDialog(
            title: new Text('Are you sure?'),
            content: new Text('Do you want to exit an App'),
            actions: <Widget>[
              new FlatButton(
                onPressed: () => Navigator.of(context).pop(false),
                child: new Text('No'),
              ),
              new FlatButton(
                onPressed: () {
                  _saveList(todoList);
                  Navigator.of(context).pop(true);
                },
                child: new Text('Yes'),
              ),
            ],
          ),
        )) ??
        false;
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: _onWillPop,
      child: SafeArea(
        child: _isLoading
            ? Center(
                child: CircularProgressIndicator(),
              )
            : Container(
                child: Column(
                  children: <Widget>[
                    Padding(
                      padding: const EdgeInsets.all(8.0),
                      child: TextField(
                        decoration: InputDecoration(
                          hintText: 'Add Items',
                        ),
                        controller: _todoController,
                        onSubmitted: (text) {
                          // do what you want with the text
                          todoList.add(_todoController.text);
                          _todoController.clear();
                          setState(() {});
                        },
                      ),
                    ),
                    todoList == null
                        ? Container(
                            child: Center(
                              child: Text('Please Add the items'),
                            ),
                          )
                        : ListView.builder(
                            shrinkWrap: true,
                            itemCount: todoList.length,
                            itemBuilder: (BuildContext context, int index) {
                              return Card(
                                child: Padding(
                                  padding: const EdgeInsets.all(8.0),
                                  child: Text(todoList[index]),
                                ),
                              );
                            },
                          ),
                  ],
                ),
              ),
      ),
    );
  }
}

And let me know if it works

Answer 2

As a basic implementation, I would say you should use shared preference it uses key values to store data, and it's pretty easy to use the data will remain until you clear your cache to uninstall it.

https://pub.dev/packages/shared_preferences