content: import 'package:flutter/material.dart';
  
  void main() => runApp(MyApp());
  
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: MyHomePage(title: 'Stepper'),
      );
    }
  }
  
  class MyHomePage extends StatefulWidget {
    MyHomePage({Key key, this.title}) : super(key: key);
  
    final String title;
  
    @override
    _MyHomePageState createState() => _MyHomePageState();
  }
  
  class _MyHomePageState extends State<MyHomePage> {
    int _currentStep = 0;
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Stepper(
          type: StepperType.horizontal,
          currentStep: _currentStep,
          onStepTapped: (int step) => setState(() => _currentStep = step),
          onStepContinue: _currentStep < 2 ? () => setState(() => _currentStep += 1) : null,
          onStepCancel: _currentStep > 0 ? () => setState(() => _currentStep -= 1) : null,
          steps: <Step>[
            Step(
              title: const Text('ステップ1'),
              subtitle: const Text('subtitle'),
              content: const Text('最初のステップです。'),
              isActive: _currentStep >= 0,
              state: _currentStep >= 0 ? StepState.complete : StepState.disabled,
            ),
            Step(
              title: const Text('ステップ2'),
              content: const Text('2番目のステップです。'),
              isActive: _currentStep >= 0,
              state: _currentStep >= 1 ? StepState.complete : StepState.disabled,
            ),
            Step(
              title: const Text('ステップ3'),
              content: const Text('最後のステップです。'),
              isActive: _currentStep >= 0,
              state: _currentStep >= 2 ? StepState.complete : StepState.disabled,
            ),
          ],
        ),
      );
    }
  }
  