AiKeyboard2025/lib/widget/birthday_date_picker.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';

class BirthdayDatePicker extends StatefulWidget {
  final DateTime initialDate;
  final DateTime minimumDate;
  final DateTime maximumDate;
  final void Function(DateTime) onDateChanged;
  // 中间背景色
  final Color backgroundColor;

  const BirthdayDatePicker({
    super.key,
    required this.initialDate,
    required this.minimumDate,
    required this.maximumDate,
    required this.onDateChanged,
    this.backgroundColor = const Color.fromRGBO(255, 255, 255, 0.6),
  });

  @override
  State<BirthdayDatePicker> createState() => _BirthdayDatePickerState();
}

class _BirthdayDatePickerState extends State<BirthdayDatePicker> {
  late int selectedYear;
  late int selectedMonth;
  late int selectedDay;

  @override
  void initState() {
    super.initState();
    selectedYear = widget.initialDate.year;
    selectedMonth = widget.initialDate.month;
    selectedDay = widget.initialDate.day;
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 150.h,
      child: Stack(
        children: [
          Positioned(
            bottom: 57.h, // Position at the bottom
            left: 0,
            right: 0,
            top: 57.h,
            child: Container(
              height: 36.h,
              decoration: BoxDecoration(
                color: widget.backgroundColor, // Background color
                borderRadius: BorderRadius.circular(14.r),
              ),
            ),
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              _buildPickerBuilder(
                count: widget.maximumDate.year - widget.minimumDate.year + 1,
                initialIndex: selectedYear - widget.minimumDate.year,
                itemBuilder: (index) => '${widget.minimumDate.year + index}年',
                onSelectedItemChanged: (index) {
                  setState(() {
                    selectedYear = widget.minimumDate.year + index;
                    _adjustMonthAndDay();
                    _notify();
                  });
                },
              ),
              _buildPickerBuilder(
                count: _getMaxMonth(),
                initialIndex: selectedMonth - 1,
                itemBuilder: (index) => '${index + 1}月',
                onSelectedItemChanged: (index) {
                  setState(() {
                    selectedMonth = index + 1;
                    _adjustDayForMonth();
                    _notify();
                  });
                },
              ),
              _buildPickerBuilder(
                count: _getMaxDay(),
                initialIndex: selectedDay - 1,
                itemBuilder: (index) => '${index + 1}日',
                onSelectedItemChanged: (index) {
                  setState(() {
                    selectedDay = index + 1;
                    _notify();
                  });
                },
              ),
            ],
          ),

          // Positioned Stack item (will be at the bottom of the Row)
        ],
      ),
    );
  }

  Widget _buildPickerBuilder({
    required int count,
    required int initialIndex,
    required String Function(int) itemBuilder,
    required Function(int) onSelectedItemChanged,
  }) {
    return Expanded(
      child: ListWheelScrollView.useDelegate(
        controller: FixedExtentScrollController(initialItem: initialIndex),
        itemExtent: 36.h,
        onSelectedItemChanged: onSelectedItemChanged,
          overAndUnderCenterOpacity: 0.35,
        childDelegate: ListWheelChildBuilderDelegate(
          builder: (context, index) {
            // 判断选中项
            bool isSelected = index == initialIndex;
            return Container(
              alignment: Alignment.center,
              color: Colors.transparent,
              child: Text(
                itemBuilder(index),
                style: TextStyle(
                  fontSize: 16.sp,

                  color: isSelected ? Colors.black : Colors.black,
                ),
              ),
            );
          },
          childCount: count,
        ),
      ),
    );
  }

  void _adjustMonthAndDay() {
    if (selectedYear == widget.maximumDate.year &&
        selectedMonth > widget.maximumDate.month) {
      selectedMonth = widget.maximumDate.month;
    }
    _adjustDayForMonth();
  }

  void _adjustDayForMonth() {
    int maxDay = _getMaxDay();
    if (selectedDay > maxDay) {
      selectedDay = maxDay;
    }
  }

  int _getMaxMonth() {
    if (selectedYear == widget.maximumDate.year) {
      return widget.maximumDate.month;
    }
    return 12;
  }

  int _getMaxDay() {
    if (selectedYear == widget.maximumDate.year &&
        selectedMonth == widget.maximumDate.month) {
      return widget.maximumDate.day;
    }
    return _getDaysInMonth(selectedYear, selectedMonth);
  }

  int _getDaysInMonth(int year, int month) {
    switch (month) {
      case 2:
        if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
          return 29;
        }
        return 28;
      case 4:
      case 6:
      case 9:
      case 11:
        return 30;
      default:
        return 31;
    }
  }

  void _notify() {
    final selectedDate = DateTime(selectedYear, selectedMonth, selectedDay);
    widget.onDateChanged(selectedDate);
  }
}