Flutter搜索算法插件search_algorithm的使用

Flutter搜索算法插件search_algorithm的使用

搜索算法

search_algorithm 是一个Dart包，提供了多种搜索算法的实现，包括二分查找（Binary Search）、线性查找（Linear Search）和跳跃查找（Jump Search）。每个搜索函数接受一个数据列表（可以是 String 或 int 类型）和要查找的数据，如果找到则返回索引，否则返回 -1。该包还提供了每种搜索方法所花费的时间信息。

特点

• 线性查找：一种直接的查找算法，逐个检查列表中的元素，直到找到目标元素或遍历完列表。
• 二分查找：一种更高效的排序列表查找算法，通过不断将搜索区间分成两半来查找。
• 跳跃查找：一种在块状元素中进行查找的算法，适用于排序列表，时间复杂度较低。

安装

在你的 pubspec.yaml 文件的依赖项部分添加以下行：

dependencies:
  search_algorithms: ^1.0.2

使用

以下是一个完整的示例，展示了如何在Flutter应用中使用 search_algorithm 插件。

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

void main() {
  runApp(const SearchAlgorithmsApp());
}

class SearchAlgorithmsApp extends StatelessWidget {
  const SearchAlgorithmsApp({super.key});

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: '搜索算法示例',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const SearchScreen(),
    );
  }
}

class SearchScreen extends StatefulWidget {
  const SearchScreen({super.key});

  [@override](/user/override)
  State<SearchScreen> createState() => _SearchScreenState();
}

class _SearchScreenState extends State<SearchScreen> {
  final List<int> intList = List.generate(10000, (index) => index);
  final List<String> stringList = List.generate(10000, (index) => 'Item$index');
  final TextEditingController _searchController = TextEditingController();
  String _searchResult = '';
  String _searchTime = '';
  late int index;

  void _performSearch(String searchKey, String algorithm) {
    Duration duration;

    final int searchKeyInt = int.tryParse(searchKey);
    final bool isIntSearch = searchKeyInt != null;

    switch (algorithm) {
      case '线性查找':
        duration = SearchAlgorithms.measureTime(() {
          index = isIntSearch
              ? SearchAlgorithms.linearSearch(intList, searchKeyInt!)
              : SearchAlgorithms.linearSearch(stringList, searchKey);
        });
        break;
      case '二分查找':
        duration = SearchAlgorithms.measureTime(() {
          index = isIntSearch
              ? SearchAlgorithms.binarySearch(intList, searchKeyInt!)
              : SearchAlgorithms.binarySearch(stringList, searchKey);
        });
        break;
      case '跳跃查找':
        duration = SearchAlgorithms.measureTime(() {
          index = isIntSearch
              ? SearchAlgorithms.jumpSearch(intList, searchKeyInt!)
              : SearchAlgorithms.jumpSearch(stringList, searchKey);
        });
        break;
      default:
        index = -1;
        duration = Duration.zero;
    }

    setState(() {
      _searchResult = index == -1 ? '未找到' : '在索引 $index 处找到';
      _searchTime = '耗时: ${duration.inMicroseconds} 微秒';
    });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('搜索算法示例'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _searchController,
              decoration: const InputDecoration(
                labelText: '输入搜索关键字',
              ),
              keyboardType: TextInputType.text,
            ),
            const SizedBox(height: 16.0),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: [
                Expanded(
                  child: ElevatedButton(
                    onPressed: () =>
                        _performSearch(_searchController.text, '线性查找'),
                    child: const Text('线性查找'),
                  ),
                ),
                Expanded(
                  child: ElevatedButton(
                    onPressed: () =>
                        _performSearch(_searchController.text, '二分查找'),
                    child: const Text('二分查找'),
                  ),
                ),
                Expanded(
                  child: ElevatedButton(
                    onPressed: () =>
                        _performSearch(_searchController.text, '跳跃查找'),
                    child: const Text('跳跃查找'),
                  ),
                ),
              ],
            ),
            const SizedBox(height: 16.0),
            Text(
              _searchResult,
              style:
                  const TextStyle(fontSize: 16.0, fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 8.0),
            Text(
              _searchTime,
              style: const TextStyle(fontSize: 16.0, color: Colors.grey),
            ),
          ],
        ),
      ),
    );
  }
}