stepper_demo.dart

import 'package:flutter/material.dart';

class StepperDemo extends StatefulWidget {
  @override
  _StepperDemoState createState() => _StepperDemoState();
}

class _StepperDemoState extends State<StepperDemo> {
  int _currentStep = 0;
  StepperType stepperType = StepperType.vertical;
  

  @override
  Widget build(BuildContext context) {
    return  Scaffold(
        appBar: AppBar(
          automaticallyImplyLeading: false,
            title: Text('Flutter Stepper Demo'),
          centerTitle: true,
        ),
        body:  Container(
          child: Column(
            children: [
              Expanded(
                child: Stepper(
                  type: stepperType,
                  physics: ScrollPhysics(),
                  currentStep: _currentStep,
                  onStepTapped: (step) => tapped(step),
                  onStepContinue:  continued,
                  onStepCancel: cancel,
                  steps: <Step>[
                     Step(
                      title: new Text('Account'),
                      content: Column(
                        children: <Widget>[
                          TextFormField(
                            decoration: InputDecoration(labelText: 'Email Address'),
                          ),
                          TextFormField(
                            decoration: InputDecoration(labelText: 'Password'),
                          ),
                        ],
                      ),
                      isActive: _currentStep >= 0,
                      state: _currentStep >= 0 ?
                      StepState.complete : StepState.disabled,
                    ),
                     Step(
                      title: new Text('Address'),
                      content: Column(
                        children: <Widget>[
                          TextFormField(
                            decoration: InputDecoration(labelText: 'Home Address'),
                          ),
                          TextFormField(
                            decoration: InputDecoration(labelText: 'Postcode'),
                          ),
                        ],
                      ),
                      isActive: _currentStep >= 0,
                      state: _currentStep >= 1 ?
                      StepState.complete : StepState.disabled,
                    ),
                     Step(
                      title: new Text('Mobile Number'),
                      content: Column(
                        children: <Widget>[
                          TextFormField(
                            decoration: InputDecoration(labelText: 'Mobile Number'),
                          ),
                        ],
                      ),
                      isActive:_currentStep >= 0,
                      state: _currentStep >= 2 ?
                      StepState.complete : StepState.disabled,
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          child: Icon(Icons.list),
          onPressed: switchStepsType,
        ),

    );
  }
  switchStepsType() {
    setState(() => stepperType == StepperType.vertical
        ? stepperType = StepperType.horizontal
        : stepperType = StepperType.vertical);
  }

  tapped(int step){
    setState(() => _currentStep = step);
  }

  continued(){
    _currentStep < 2 ?
        setState(() => _currentStep += 1): null;
  }
  cancel(){
    _currentStep > 0 ?
        setState(() => _currentStep -= 1) : null;
  }
}