Implement a form wizard form

wizard_form.dart

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

main() {
  runApp(
    MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: VerticalForm(),
      ),
    ),
  );
}

// https://github.com/matthew-carroll/flutter_example_form_focus.git
class VerticalForm extends StatefulWidget {
  @override
  _VerticalFormState createState() => new _VerticalFormState();
}

class _VerticalFormState extends State<VerticalForm> {

  FocusNode focusNode1;
  FocusNode focusNode2;
  FocusNode focusNode3;
  FocusNode focusNode4;
  FocusNode focusNode5;
  FocusNode focusNode6;
  TextEditingController controller1 = new TextEditingController();
  TextEditingController controller2 = new TextEditingController();
  TextEditingController controller3 = new TextEditingController();
  GlobalKey<FormState> formKey1 = new GlobalKey<FormState>();
  var data = {};
  int currentNode = 1; 
  List<FocusNode> nodeList;

  @override
  void initState() {
    super.initState();
    print("INIT FORM WIZARD");
    focusNode1 = new FocusNode();  
    focusNode2 = new FocusNode();
    focusNode3 = new FocusNode();
    focusNode4 = new FocusNode();
    focusNode5 = new FocusNode();
    focusNode6 = new FocusNode();

    controller1.addListener(_ctrlOneListener);
    nodeList = [focusNode1, focusNode2, focusNode3, focusNode4, focusNode5, focusNode6];
  }

  void _ctrlOneListener(){
    String val = controller1.text;
    print("controller one value ${val}");
  }

  @override
  void dispose() {
    print("DISPOSED FORM WIZARD");
    currentNode = 0;
    focusNode1.dispose();
    focusNode2.dispose();
    focusNode3.dispose();
    focusNode4.dispose();
    focusNode5.dispose();
    super.dispose();
  }

  Widget _buildTextFormField({
    InputDecoration decoration,
    Key key,
    String hintText,
    TextInputAction keyboardAction = TextInputAction.done,
    Function(String) onSubmitted,
    FocusNode focusNode,
    TextEditingController ctrl
  }) {
    return new FormField(
      builder: (FormFieldState fieldState) {
        return new TextField(
          key: key,
          controller: ctrl,
          decoration: new InputDecoration(
            hintText: hintText,
          ),
          textInputAction: keyboardAction,
          onSubmitted: onSubmitted,
          focusNode: focusNode,
          
        );
      },
    );
  }

  void toNext(){
    setState(() {
                    currentNode = currentNode % nodeList.length;
                    FocusScope.of(context).requestFocus(nodeList[currentNode]);
                    currentNode++;
                  });
  }

  @override
  Widget build(BuildContext context) {
    // focusNode1.addListener(listener)
    print("CURRENT NODE ${currentNode}");
    return new SingleChildScrollView(
      child: new Padding(
        padding: const EdgeInsets.all(16.0),
        child: new Form(
          key: formKey1,
          child: new Column(
            children: <Widget>[
              SizedBox(height: 100.0,),
              Text("Tell me about yourself, Mr. Anderson"),
              SizedBox(height: 50.0,),
              _buildTextFormField(
                // ctrl: controller1,
                // decoration: InputDecoration(labelText: "Go to next"),
                hintText: 'Controller 1',
               keyboardAction: TextInputAction.next,
                // keyboardAction: TextInputAction.none,
                focusNode: focusNode1,
               onSubmitted: (String value) {
                 data.addAll({"controllerOneValue":value});

                 FocusScope.of(context).requestFocus(focusNode2);
               },
              ),
              MaterialButton(
                child: Text("NEXT"),
                onPressed: toNext,
              ),
              SizedBox(height: 100.0,),
              Text("Do you wish to take the red pill, or the blue pill?"),
              SizedBox(height: 50.0,),
              _buildTextFormField(
                // ctrl: controller2,
                hintText: 'Controller 2',
               keyboardAction: TextInputAction.next,
                // keyboardAction: TextInputAction.unspecified,
                focusNode: focusNode2,
               onSubmitted: (String value) {
                 FocusScope.of(context).requestFocus(focusNode3);
               },
              ),
              MaterialButton(
                child: Text("NEXT"),
                onPressed: toNext,
              ),
              SizedBox(height: 100.0,),
              Text("Do you wish to take the red pill, or the blue pill?"),
              SizedBox(height: 50.0,),
              _buildTextFormField(
                hintText: 'Done',
                keyboardAction: TextInputAction.done,
                focusNode: focusNode3,
                onSubmitted: (String value) {
                  print('Handling first name submission');
                  FocusScope.of(context).requestFocus(focusNode4);
                },
              ),
              MaterialButton(
                child: Text("NEXT"),
                onPressed: toNext,
              ),
              _buildTextFormField(
                hintText: 'Go',
                keyboardAction: TextInputAction.go, // TextInputAction.search | next | send ...
                focusNode: focusNode4,
                onSubmitted: (String value) {
                  print('Handling last name submission');
                  FocusScope.of(context).requestFocus(focusNode5);
                },
              ),
              TextFormField(
                keyboardType: TextInputType.multiline,
                focusNode: focusNode5,
                decoration: InputDecoration(icon: Icon(Icons.ac_unit), hintText: "First Name"),
                controller: controller1,
                onSaved: (formData){
                  print("field ${formData}");
                },
              ),
              Row(
                mainAxisAlignment:MainAxisAlignment.start,
                children: <Widget>[
                  Expanded(
                    child: TextFormField(
                  keyboardType: TextInputType.multiline,
                  focusNode: focusNode6,
                  decoration: InputDecoration(icon: Icon(Icons.ac_unit), hintText: "Last Name"),
                  // keyboardType: TextInputType.text,
                  controller: controller2,  // required but not really needed for data
                  onSaved: (fieldData){
                    String c1 = controller1.text; 
                    String c2 = controller2.text;
                    print('TEXT FIELD 1 SAVED ${c1} ${c2}');
                    data.addAll({"controllerOneValue": c1});
                    data.addAll({"controllerTwoValue": c2});
                    data.addAll({"controllerThreeValue": fieldData});
                    print("TOTAL DATA ${data}");
                    print("FIELD DATA ${fieldData}"); 
                  },
                ),
                  ),
                  
                Icon(Icons.access_time),
              ],),
              
              MaterialButton(
                color: Colors.blueAccent[300],
                child: new Text("SUBMIT"),
                onPressed: (){
                  final FormState form1State = formKey1.currentState;
                  form1State.save();
                  
                  controller1.clear();
                  controller2.clear();
                  // print('TEXT FIELD 1 SAVED ${c1} ${c2}');
                },
              ),
              
            ],
          ),
        ),
      ),
    );
  }
}