当然，下面是一个关于如何在Flutter应用中使用custom_calendar_picker插件的示例代码。这个插件允许用户选择一个日期范围或者单个日期，非常适合需要日历选择功能的场景。

首先，确保你已经在pubspec.yaml文件中添加了custom_calendar_picker依赖：

dependencies:
  flutter:
    sdk: flutter
  custom_calendar_picker: ^x.y.z  # 请替换为最新版本号

然后运行flutter pub get来安装依赖。

接下来是一个完整的示例代码，展示如何使用custom_calendar_picker来选择日期范围：

import 'package:flutter/material.dart';
import 'package:custom_calendar_picker/custom_calendar_picker.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Calendar Picker Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: CalendarPickerDemo(),
    );
  }
}

class CalendarPickerDemo extends StatefulWidget {
  @override
  _CalendarPickerDemoState createState() => _CalendarPickerDemoState();
}

class _CalendarPickerDemoState extends State<CalendarPickerDemo> {
  DateTime? startDate;
  DateTime? endDate;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Calendar Picker Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Selected Date Range:',
              style: TextStyle(fontSize: 20),
            ),
            SizedBox(height: 20),
            Text(
              '${startDate != null ? startDate!.toLocal().toString() : 'Start Date'} - ${endDate != null ? endDate!.toLocal().toString() : 'End Date'}',
              style: TextStyle(fontSize: 18),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                _selectDateRange(context);
              },
              child: Text('Select Date Range'),
            ),
          ],
        ),
      ),
    );
  }

  void _selectDateRange(BuildContext context) async {
    final DateTime? resultStartDate = await showDatePicker(
      context: context,
      initialDate: startDate ?? DateTime.now(),
      firstDate: DateTime(2000),
      lastDate: DateTime(2101),
    );

    if (resultStartDate != null && (resultStartDate != startDate)) {
      setState(() {
        startDate = resultStartDate;
      });

      final DateTime? resultEndDate = await showDatePicker(
        context: context,
        initialDate: endDate ?? resultStartDate,
        firstDate: DateTime(2000),
        lastDate: DateTime(2101),
      );

      if (resultEndDate != null) {
        setState(() {
          endDate = resultEndDate;
          if (endDate!.isBefore(startDate!)) {
            endDate = startDate; // Ensure end date is after start date
          }
        });
      }
    }
  }

  // Using CustomCalendarPicker for date range selection
  void _showCustomCalendarPicker(BuildContext context) async {
    DateTime? start, end;
    await showCupertinoModalPopup<void>(
      context: context,
      builder: (context) {
        return Container(
          height: 300,
          child: CustomCalendarPicker(
            leftPadding: 8.0,
            rightPadding: 8.0,
            topPadding: 8.0,
            bottomPadding: 8.0,
            initSelectedDate: DateTime.now(),
            firstDate: DateTime(2000),
            lastDate: DateTime(2101),
            isLoop: true,
            rowHeight: 50.0,
            selectedTextStyle: TextStyle(color: Colors.blue, fontSize: 18),
            todayTextStyle: TextStyle(color: Colors.red, fontSize: 18),
            otherMonthDayTextStyle: TextStyle(color: Colors.grey),
            onDateChanged: (date, isSelected) {
              if (isSelected) {
                if (start == null) {
                  start = date;
                } else if (end == null && date.isAfter(start!)) {
                  end = date;
                } else if (date.isBefore(start!)) {
                  start = date;
                  end = null;
                }
              } else {
                if (date == start) {
                  start = null;
                } else if (date == end) {
                  end = null;
                }
              }
            },
            onConfirm: (dates) {
              Navigator.of(context).pop();
              setState(() {
                startDate = dates.first;
                endDate = dates.last;
              });
            },
          ),
        );
      },
    );
  }

  @override
  Widget buildCustomCalendarPickerButton(BuildContext context) {
    return ElevatedButton(
      onPressed: () {
        _showCustomCalendarPicker(context);
      },
      child: Text('Select Date Range with CustomCalendarPicker'),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Calendar Picker Demo'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Selected Date Range:',
              style: TextStyle(fontSize: 20),
            ),
            SizedBox(height: 20),
            Text(
              '${startDate != null ? startDate!.toLocal().toString() : 'Start Date'} - ${endDate != null ? endDate!.toLocal().toString() : 'End Date'}',
              style: TextStyle(fontSize: 18),
            ),
            SizedBox(height: 40),
            buildCustomCalendarPickerButton(context),
          ],
        ),
      ),
    );
  }
}

注意：上面的代码包含了两种选择日期范围的方法：

1. 使用showDatePicker两次选择开始日期和结束日期（这是Flutter自带的方法）。
2. 使用CustomCalendarPicker插件来选择日期范围。

为了简化示例，我合并了两个方法的代码，但在实际使用中，你可能只需要其中一种方法。

你可以根据实际需求调整UI和逻辑。希望这个示例能帮助你更好地理解和使用custom_calendar_picker插件。