Flutter搜索功能插件search_methods的使用

搜索方法

此包将帮助您以三种不同的方式从列表中搜索一个项目。

search_methods的特性

• 线性搜索
• 二分搜索
• 跳跃搜索

search_methods的使用说明

前提条件

在开始使用此插件之前，请确保您的项目已经配置好 Dart 和 Flutter 环境。您可以通过以下命令安装插件：

flutter pub add search_methods

示例代码

以下是一个完整的示例代码，展示如何使用 search_methods 插件进行线性搜索、二分搜索和跳跃搜索。

完整示例代码

import 'package:flutter/material.dart';
import 'package:search_methods/search_methods.dart'; // 导入 search_methods 包

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: SearchExamplePage(),
    );
  }
}

class SearchExamplePage extends StatefulWidget {
  @override
  _SearchExamplePageState createState() => _SearchExamplePageState();
}

class _SearchExamplePageState extends State<SearchExamplePage> {
  final List<int> intList = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];
  final List<String> stringList = ['apple', 'banana', 'cherry', 'date', 'elderberry'];

  int intTarget = 50;
  String stringTarget = 'cherry';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Search Methods Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              onPressed: () {
                performLinearSearch();
              },
              child: Text('Perform Linear Search'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                performBinarySearch();
              },
              child: Text('Perform Binary Search'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                performJumpSearch();
              },
              child: Text('Perform Jump Search'),
            ),
          ],
        ),
      ),
    );
  }

  void performLinearSearch() {
    print('Linear Search:');
    int intIndex = SearchAlgorithms.linearSearch(intList, intTarget);
    print('Index of $intTarget in intList: $intIndex');

    int stringIndex = SearchAlgorithms.linearSearch(stringList, stringTarget);
    print('Index of $stringTarget in stringList: $stringIndex');
  }

  void performBinarySearch() {
    print('\nBinary Search:');
    int intIndex = SearchAlgorithms.binarySearch(intList, intTarget);
    print('Index of $intTarget in intList: $intIndex');

    int stringIndex = SearchAlgorithms.binarySearch(stringList, stringTarget);
    print('Index of $stringTarget in stringList: $stringIndex');
  }

  void performJumpSearch() {
    print('\nJump Search:');
    int intIndex = SearchAlgorithms.jumpSearch(intList, intTarget);
    print('Index of $intTarget in intList: $intIndex');

    int stringIndex = SearchAlgorithms.jumpSearch(stringList, stringTarget);
    print('Index of $stringTarget in stringList: $stringIndex');
  }
}

代码解释

1. 导入包：

   import 'package:search_methods/search_methods.dart';
   

   导入 search_methods 包以便使用其提供的搜索算法。

2. 定义列表和目标值：

   final List<int> intList = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];
   final List<String> stringList = ['apple', 'banana', 'cherry', 'date', 'elderberry'];
   int intTarget = 50;
   String stringTarget = 'cherry';
   

3. 线性搜索：

   int intIndex = SearchAlgorithms.linearSearch(intList, intTarget);
   print('Index of $intTarget in intList: $intIndex');
   

4. 二分搜索：

   int intIndex = SearchAlgorithms.binarySearch(intList, intTarget);
   print('Index of $intTarget in intList: $intIndex');
   

   注意：二分搜索要求列表必须已排序。

5. 跳跃搜索：

   int intIndex = SearchAlgorithms.jumpSearch(intList, intTarget);
   print('Index of $intTarget in intList: $intIndex');