flutter_integrated_whb/lib/customWidget/bottom_picker.dart

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'package:qhd_prevention/customWidget/toast_util.dart';

/// 通用底部弹窗选择器
/// Example:
/// ```dart
/// final choice = await BottomPicker.show<String>(
///   context,
///   items: ['选项1', '选项2', '选项3'],
///   itemBuilder: (item) => Text(item, textAlign: TextAlign.center),
///   initialIndex: 1,
/// );
/// if (choice != null) {
///   // 用户点击确定并选择了 choice
/// }
/// ```
class BottomPicker {
  /// 显示底部选择器弹窗
  ///
  /// [items]: 选项列表
  /// [itemBuilder]: 每个选项的展示 Widget
  /// [initialIndex]: 初始选中索引
  /// [itemExtent]: 列表行高
  /// [height]: 弹窗总高度
  static Future<T?> show<T>(
    BuildContext context, {
    required List<T> items,
    required Widget Function(T item) itemBuilder,
    int initialIndex = 0,
    double itemExtent = 50.0,
    double height = 250,
  }) {
    if (items.isEmpty) return Future.value(null);

    // 确保初始索引合法
    final safeIndex = initialIndex.clamp(0, items.length - 1);
    // 当前选中项
    T selected = items[safeIndex];

    return showModalBottomSheet<T>(
      context: context,
      backgroundColor: Colors.white,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(12)),
      ),
      builder: (ctx) {
        return SizedBox(
          height: height,
          child: Column(
            children: [
              // 按钮行
              Padding(
                padding: const EdgeInsets.symmetric(
                  horizontal: 16,
                  vertical: 8,
                ),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    TextButton(
                      onPressed: () {
                        FocusScope.of(context).unfocus();
                        Navigator.of(ctx).pop();
                      },
                      child: const Text('取消', style: TextStyle(color: Colors.black54, fontSize: 16),),
                    ),
                    TextButton(
                      onPressed: () {
                        FocusScope.of(context).unfocus();
                        Navigator.of(ctx).pop(selected);
                      },
                      child: const Text('确定', style: TextStyle(color: Colors.blue, fontSize: 16),),
                    ),
                  ],
                ),
              ),
              const Divider(height: 1),
              // 滚动选择器
              Expanded(
                child: CupertinoPicker(
                  scrollController: FixedExtentScrollController(
                    initialItem: initialIndex,
                  ),
                  itemExtent: itemExtent,
                  onSelectedItemChanged: (index) {
                    selected = items[index];
                  },
                  // 把 itemBuilder 返回的 Widget 用 Center 包一层
                  children: items.map((item) => Center(child: itemBuilder(item))).toList(),
                ),
              ),

            ],
          ),
        );
      },
    );
  }
}