import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Padding(
              child: TheItem(),
              padding: EdgeInsets.all(40),
            ),
            RaisedButton(
              child: Text("Press me!"),
              onPressed: () {
                Navigator.of(context)
                    .push(MaterialPageRoute(builder: (context) {
                  return ChildPage();
                }));
              },
            )
          ],
        ),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class ChildPage extends StatefulWidget {
  @override
  _ChildPageState createState() => _ChildPageState();
}

class _ChildPageState extends State<ChildPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Child Page"),
      ),
      body: Center(
          child:
              TheItem()), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class TheItem extends StatelessWidget {
  final TextEditingController textController = TextEditingController();
  FocusNode focusNode = FocusNode();

  TheItem() {
    focusNode.addListener(() {
      if (focusNode.hasFocus) {
        textController.selection =
            TextSelection(baseOffset: 0, extentOffset: textController.text.length);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    textController.text = "Hola";
    return Dismissible(
      key: Key("potatoes"),
      onDismissed: (direction) {},
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Padding(
            child: TextField(
              focusNode: focusNode,
              controller: textController,
            ),
            padding: EdgeInsets.all(40),
          ),
        ],
      ),
    );
  }
}