Flutter实体提取插件 learning_entity_extraction 的使用

简介

learning_entity_extraction 是一个用于在Flutter应用中进行文本实体提取的插件。它基于ML Kit，能够识别特定类型的实体（如地址、日期时间、电子邮件等），从而增强用户与文本的交互体验。

功能特点

• 识别静态文本中的具体实体。
• 支持多种语言。
• 提供了对提取到的实体执行不同操作的功能。

开始使用

添加依赖

首先，在你的Flutter项目的pubspec.yaml文件中添加以下依赖：

dependencies:
  learning_entity_extraction: ^0.0.2

然后运行命令：

flutter pub get

导入包

在需要使用的文件中导入该插件：

import 'package:learning_entity_extraction/learning_entity_extraction.dart';

实体提取示例

下面是一个完整的示例项目，演示如何使用learning_entity_extraction从用户输入的文本中提取实体，并展示结果。

示例代码

import 'package:flutter/material.dart';
import 'package:learning_entity_extraction/learning_entity_extraction.dart';
import 'package:provider/provider.dart';

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.lightBlue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
        primaryTextTheme: TextTheme(headline6: TextStyle(color: Colors.white)),
      ),
      home: ChangeNotifierProvider(
        create: (_) => EntityExtractionState(),
        child: EntityExtractionPage(),
      ),
    );
  }
}

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

class _EntityExtractionPageState extends State<EntityExtractionPage> {
  TextEditingController _controller = TextEditingController();
  EntityExtractor _extractor = EntityExtractor();

  EntityExtractionState get state => Provider.of(context, listen: false);

  [@override](/user/override)
  void initState() {
    super.initState();
    WidgetsBinding.instance?.addPostFrameCallback((_) async {
      //await testModelManager();
      //await testExtraction();
    });
  }

  [@override](/user/override)
  void dispose() {
    _controller.dispose();
    _extractor.dispose();
    super.dispose();
  }

  Future<void> _extract() async {
    state.startProcessing();
    List extractedItems = await _extractor.extract(_controller.text);
    state.data =
        extractedItems.map((item) => item.toString()).toList().join('\n\n');
    state.stopProcessing();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text('Entity Extraction'),
      ),
      body: SingleChildScrollView(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            SizedBox(height: 20),
            TextField(
              autofocus: true,
              controller: _controller,
              textAlign: TextAlign.center,
              textAlignVertical: TextAlignVertical.center,
              keyboardType: TextInputType.multiline,
              decoration: InputDecoration(contentPadding: EdgeInsets.symmetric(horizontal: 18)),
              minLines: 5,
              maxLines: 10,
              style: TextStyle(fontSize: 18, color: Colors.blueGrey[700]),
              onChanged: (_) => state.clear(),
            ),
            SizedBox(height: 15),
            ElevatedButton(
              onPressed: _extract,
              child: Text('Extract Entities'),
            ),
            SizedBox(height: 25),
            Consumer<EntityExtractionState>(
              builder: (_, state, __) => Center(
                child: Container(
                  padding: EdgeInsets.symmetric(horizontal: 15),
                  child: Text(
                    state.data,
                    textAlign: TextAlign.center,
                    style: TextStyle(fontSize: 13),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class EntityExtractionState extends ChangeNotifier {
  String _data = '';
  bool _isProcessing = false;

  String get data => _data;
  bool get isProcessing => _isProcessing;

  void startProcessing() {
    _data = 'Extracting...';
    _isProcessing = true;
    notifyListeners();
  }

  void stopProcessing() {
    _isProcessing = false;
    notifyListeners();
  }

  set data(String data) {
    _data = data;
    notifyListeners();
  }

  void clear() {
    _data = '';
    notifyListeners();
  }
}