string_list_updating

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(
          listFixed: [1, 2], stringFixed: "String"),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.stringFixed, this.listFixed}) : super(key: key);

  final List<int> listFixed;
  final String stringFixed;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  List<int> _listVariable;
  String _stringVariable;

  @override
  void initState() {
    _stringVariable = widget.stringFixed;
    _listVariable = widget.listFixed;
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("hello"),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              _stringVariable,
            ),
            Text(
              "Should not update: ${widget.stringFixed}",
            ),
            Text(_listVariable.toString()),
            Text("Should not update: ${widget.listFixed.toString()}"),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          setState(() {
            _counter++;
            _listVariable.add(_counter);
            _stringVariable = "$_stringVariable $_counter";
          });
        },
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}