Flutter语言学习插件 learning_language 的使用

learning_language 是一个方便在Flutter中使用ML Kit进行语言识别的插件。通过该插件，我们可以轻松地识别用户提供的文本的语言。

目录

• 安装
• 使用方法
  • 识别语言
  • 识别可能的语言
  • 释放资源
• 示例项目

安装

首先，在你的Flutter项目中添加依赖：

$ flutter pub add learning_language

或者在 pubspec.yaml 文件中手动添加：

dependencies:
  learning_language: ^0.0.3+2

然后运行 flutter pub get 来获取依赖。

使用方法

导入包

首先导入 learning_language 包：

import 'package:learning_language/learning_language.dart';

识别语言

以下是一个简单的例子，展示如何使用 LanguageIdentifier 来识别一段文本的语言：

String text = 'Baby, you light up my world like nobody else';
LanguageIdentifier identifier = LanguageIdentifier();
String language = await identifier.identify(text);
print(language); // 输出可能是 "en" 表示英语

识别可能的语言

有时我们不仅想知道主要的语言，还想了解其他可能性。可以使用以下代码来获取所有可能的语言：

String text = 'Baby, you light up my world like nobody else';
LanguageIdentifier identifier = LanguageIdentifier();
List<IdentifiedLanguage> possibleLanguages = await identifier.idenfityPossibleLanguages(text);

String languages = possibleLanguages.map((item) => item.language).toList().join(', ');

print('Possible Languages: $languages');

释放资源

为了防止内存泄漏，请确保在不再需要时调用 dispose() 方法：

identifier.dispose();

示例项目

你可以从这里查看完整的示例项目。

下面是一个更复杂的示例应用，它允许用户输入文本并识别其语言或可能的语言：

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:learning_language/learning_language.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: (_) => IdentifyLanguageState(),
        child: IdentifyLanguagePage(),
      ),
    );
  }
}

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

class _IdentifyLanguagePageState extends State<IdentifyLanguagePage> {
  TextEditingController _controller = TextEditingController();
  LanguageIdentifier _identifier = LanguageIdentifier();

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

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

  Future<void> _startIdentifying() async {
    state.startProcessing();

    String language = await _identifier.identify(_controller.text);
    state.data = language == 'und' ? 'Not Identified' : language.toUpperCase();
    state.stopProcessing();
  }

  Future<void> _startIdentifyingPossibleLanguages() async {
    state.startProcessing();

    List<IdentifiedLanguage> languages = await _identifier.idenfityPossibleLanguages(_controller.text);

    String result = '';
    for (IdentifiedLanguage l in languages) {
      result += '${l.language.toUpperCase()} (${l.confidence.toString()})\n';
    }

    state.data = result;
    state.stopProcessing();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text('Language Identification'),
      ),
      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: _startIdentifying,
              child: Text('Identify Language'),
            ),
            SizedBox(height: 8),
            ElevatedButton(
              onPressed: _startIdentifyingPossibleLanguages,
              child: Text('Identify Possible Languages'),
            ),
            SizedBox(height: 25),
            Consumer<IdentifyLanguageState>(
              builder: (_, state, __) => Center(
                child: Text(
                  state.isProcessing ? 'Identifying language...' : state.data,
                  textAlign: TextAlign.center,
                  style: TextStyle(
                    fontWeight: FontWeight.bold,
                    fontSize: 20,
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

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

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

  void startProcessing() {
    _isProcessing = true;
    notifyListeners();
  }

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

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

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