import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: UserDataForm(),
    );
  }
}

class UserDataForm extends StatefulWidget {
  @override
  _UserDataFormState createState() => _UserDataFormState();
}

class _UserDataFormState extends State<UserDataForm> {
  final _formKey = GlobalKey<FormState>();
  String _name = '';
  int _age = 0;
  double _height = 0.0;

  void _submitData() {
    if (_formKey.currentState!.validate()) {
      _formKey.currentState!.save();
      // Zeigt einen Dialog mit den gespeicherten Daten
      showDialog(
        context: context,
        builder: (context) {
          return AlertDialog(
            title: Text('Gespeicherte Daten'),
            content: Text(
                'Name: $_name\nAlter: $_age\nGröße: ${_height.toStringAsFixed(2)} m'),
            actions: <Widget>[
              TextButton(
                child: Text('OK'),
                onPressed: () {
                  Navigator.of(context).pop();
                },
              ),
            ],
          );
        },
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Benutzerdaten-Formular'),
      ),
      body: Form(
        key: _formKey,
        child: Column(
          children: <Widget>[
            TextFormField(
              decoration: InputDecoration(labelText: 'Name'),
              onSaved: (value) {
                _name = value!;
              },
              validator: (value) {
                if (value!.isEmpty) {
                  return 'Bitte einen Namen eingeben';
                }
                return null;
              },
            ),
            TextFormField(
              decoration: InputDecoration(labelText: 'Alter'),
              keyboardType: TextInputType.number,
              onSaved: (value) {
                _age = int.parse(value!);
              },
              validator: (value) {
                if (value!.isEmpty || int.tryParse(value) == null) {
                  return 'Bitte ein gültiges Alter eingeben';
                }
                return null;
              },
            ),
            TextFormField(
              decoration: InputDecoration(labelText: 'Größe (in Metern)'),
              keyboardType: TextInputType.numberWithOptions(decimal: true),
              onSaved: (value) {
                _height = double.parse(value!);
              },
              validator: (value) {
                if (value!.isEmpty || double.tryParse(value) == null) {
                  return 'Bitte eine gültige Größe eingeben';
                }
                return null;
              },
            ),
            Padding(
              padding: const EdgeInsets.only(top: 20.0),
              child: ElevatedButton(
                onPressed: _submitData,
                child: Text('Speichern und anzeigen'),
              ),
            ),
          ],
        ),
      ),
    );
  }
}