flutter date time选择器可添加开始日期和结束日期

import 'package:flutter/material.dart';

class DatePickerExample extends StatefulWidget {
  @override
  _DatePickerExampleState createState() => _DatePickerExampleState();
}

class _DatePickerExampleState extends State<DatePickerExample> {
  DateTime startDate;
  DateTime endDate;

  Future<void> _selectStartDate(BuildContext context) async {
    final DateTime selectedDate = await showDatePicker(
      context: context,
      initialDate: startDate ?? DateTime.now(),
      firstDate: DateTime(2000),
      lastDate: endDate ?? DateTime(2100),
    );

    if (selectedDate != null) {
      setState(() {
        startDate = selectedDate;
      });
    }
  }

  Future<void> _selectEndDate(BuildContext context) async {
    final DateTime selectedDate = await showDatePicker(
      context: context,
      initialDate: endDate ?? DateTime.now(),
      firstDate: startDate ?? DateTime(2000),
      lastDate: DateTime(2100),
    );

    if (selectedDate != null) {
      setState(() {
        endDate = selectedDate;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Date Picker Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              'Start Date: ${startDate?.toString() ?? 'Not selected'}',
            ),
            RaisedButton(
              onPressed: () => _selectStartDate(context),
              child: Text('Select Start Date'),
            ),
            SizedBox(height: 20),
            Text(
              'End Date: ${endDate?.toString() ?? 'Not selected'}',
            ),
            RaisedButton(
              onPressed: () => _selectEndDate(context),
              child: Text('Select End Date'),
            ),
          ],
        ),
      ),
    );
  }
}