multiselect_popup 是一个用于 Flutter 的多选弹出框插件，允许用户从列表中选择多个项目。以下是如何使用 multiselect_popup 插件的步骤：

1. 添加依赖

首先，在 pubspec.yaml 文件中添加 multiselect_popup 插件的依赖：

dependencies:
  flutter:
    sdk: flutter
  multiselect_popup: ^1.0.0  # 请检查最新版本

然后运行 flutter pub get 来安装依赖。

2. 导入包

在需要使用 multiselect_popup 的 Dart 文件中导入包：

import 'package:multiselect_popup/multiselect_popup.dart';

3. 使用 MultiselectPopup

MultiselectPopup 是一个小部件，可以嵌入到你的 UI 中。以下是一个简单的示例，展示如何使用它：

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

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Multiselect Popup Example'),
        ),
        body: Center(
          child: MultiselectPopupExample(),
        ),
      ),
    );
  }
}

class MultiselectPopupExample extends StatefulWidget {
  [@override](/user/override)
  _MultiselectPopupExampleState createState() => _MultiselectPopupExampleState();
}

class _MultiselectPopupExampleState extends State<MultiselectPopupExample> {
  List<String> selectedItems = [];

  final List<String> items = [
    'Item 1',
    'Item 2',
    'Item 3',
    'Item 4',
    'Item 5',
  ];

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        ElevatedButton(
          onPressed: () async {
            final List<String>? result = await showDialog(
              context: context,
              builder: (BuildContext context) {
                return MultiselectPopup(
                  items: items,
                  selectedItems: selectedItems,
                  title: 'Select Items',
                  confirmText: 'OK',
                  cancelText: 'Cancel',
                );
              },
            );

            if (result != null) {
              setState(() {
                selectedItems = result;
              });
            }
          },
          child: Text('Show Multiselect Popup'),
        ),
        SizedBox(height: 20),
        Text('Selected Items: ${selectedItems.join(", ")}'),
      ],
    );
  }
}