How To Shift Focus To Next Text Field Input Using Flutter App

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final FocusNode _firstInputFocusNode = new FocusNode();
  final FocusNode _secondInputFocusNode = new FocusNode();
  final FocusNode _thirdInputFocusNode = new FocusNode();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.lightGreen,
        title: Text('Shift Text Field Focus'),
      ),
      body: Center(
        child: Padding(
          padding: EdgeInsets.symmetric(horizontal: 25.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            mainAxisSize: MainAxisSize.max,
            children: <Widget>[
              firstTextField(),
              secondTextField(),
              thirdTextField(),
            ],
          ),
        ),
      ),
    );
  }

  Widget firstTextField() {
    return TextField(
      focusNode: _firstInputFocusNode,
      textInputAction: TextInputAction.next,
      decoration: InputDecoration(hintText: "First Text Field"),
      onEditingComplete: () =>
          FocusScope.of(context).requestFocus(_secondInputFocusNode),
    );
  }

  Widget secondTextField() {
    return TextField(
      textInputAction: TextInputAction.next,
      focusNode: _secondInputFocusNode,
      decoration: InputDecoration(hintText: "Second Text Field"),
      onEditingComplete: () =>
          FocusScope.of(context).requestFocus(_thirdInputFocusNode),
    );
  }

  Widget thirdTextField() {
    return TextField(
      textInputAction: TextInputAction.next,
      focusNode: _thirdInputFocusNode,
      decoration: InputDecoration(hintText: "Third Text Field"),
      onEditingComplete: () =>
          FocusScope.of(context).requestFocus(_firstInputFocusNode),
    );
  }
}