flutter/examples/api/lib/material/date_picker/show_date_picker.0.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';

/// Flutter code sample for [showDatePicker].

void main() => runApp(const DatePickerApp());

class DatePickerApp extends StatelessWidget {
  const DatePickerApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      restorationScopeId: 'app',
      home: DatePickerExample(restorationId: 'main'),
    );
  }
}

class DatePickerExample extends StatefulWidget {
  const DatePickerExample({super.key, this.restorationId});

  final String? restorationId;

  @override
  State<DatePickerExample> createState() => _DatePickerExampleState();
}

/// RestorationProperty objects can be used because of RestorationMixin.
class _DatePickerExampleState extends State<DatePickerExample> with RestorationMixin {
  // In this example, the restoration ID for the mixin is passed in through
  // the [StatefulWidget]'s constructor.
  @override
  String? get restorationId => widget.restorationId;

  final RestorableDateTime _selectedDate = RestorableDateTime(DateTime(2021, 7, 25));
  late final RestorableRouteFuture<DateTime?> _restorableDatePickerRouteFuture = RestorableRouteFuture<DateTime?>(
    onComplete: _selectDate,
    onPresent: (NavigatorState navigator, Object? arguments) {
      return navigator.restorablePush(
        _datePickerRoute,
        arguments: _selectedDate.value.millisecondsSinceEpoch,
      );
    },
  );

  @pragma('vm:entry-point')
  static Route<DateTime> _datePickerRoute(
    BuildContext context,
    Object? arguments,
  ) {
    return DialogRoute<DateTime>(
      context: context,
      builder: (BuildContext context) {
        return DatePickerDialog(
          restorationId: 'date_picker_dialog',
          initialEntryMode: DatePickerEntryMode.calendarOnly,
          initialDate: DateTime.fromMillisecondsSinceEpoch(arguments! as int),
          firstDate: DateTime(2021),
          lastDate: DateTime(2022),
        );
      },
    );
  }

  @override
  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
    registerForRestoration(_selectedDate, 'selected_date');
    registerForRestoration(_restorableDatePickerRouteFuture, 'date_picker_route_future');
  }

  void _selectDate(DateTime? newSelectedDate) {
    if (newSelectedDate != null) {
      setState(() {
        _selectedDate.value = newSelectedDate;
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(
          content:
              Text('Selected: ${_selectedDate.value.day}/${_selectedDate.value.month}/${_selectedDate.value.year}'),
        ));
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: OutlinedButton(
          onPressed: () {
            _restorableDatePickerRouteFuture.present();
          },
          child: const Text('Open Date Picker'),
        ),
      ),
    );
  }
}