state_persistence

Description:

state persistence

State Persistence #

Persist state across app launches. By default this library store
state as a local JSON file called data.json in the applications
data directory. You can change this filename by providing another
storage mechanism.
If you do not want to store your persisted app state as a JSON
file you can extend PersistedStateStorage and provide your own
methods for saving and loading data. E.g shared_preferences or
sqflite. For those of you that are ambitious you could even
store your state on the web or even in Firebase.
To change the persisted state simply modify the values in the
data map. These changes will automatically be persisted to disk
based on the saveTimeout given to the PersistedAppState widget.
By default this value is 500 milliseconds. This timeout is used
to stop disk thrashing on multiple map changes in quick succession.
Example #
import 'package:flutter/material.dart';
import 'package:state_persistence/state_persistence.dart';

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

class App extends StatefulWidget {
@override
_AppState createState() => _AppState();
}

class _AppState extends State<App> {
TextEditingController _textController;

@override
Widget build(BuildContext context) {
return PersistedAppState(
storage: JsonFileStorage(),
child: MaterialApp(
title: 'Persistent TextField Example',
theme: ThemeData(primarySwatch: Colors.indigo),
home: Scaffold(
appBar: AppBar(title: Text('Persistent TextField Example')),
body: Container(
padding: const EdgeInsets.all(32.0),
alignment: Alignment.center,
child: PersistedStateBuilder(
builder: (BuildContext context, AsyncSnapshot<PersistedData> snapshot) {
if (snapshot.hasData) {
if (_textController == null) {
_textController = TextEditingController(text: snapshot.data['text'] ?? '');
}
return TextField(
controller: _textController,
decoration: InputDecoration(
hintText: 'Enter some text',
),
onChanged: (String value) => snapshot.data['text'] = value,
);
} else {
return CircularProgressIndicator();
}
},
),
),
),
),
);
}
}
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