316 lines
9.0 KiB
Dart
316 lines
9.0 KiB
Dart
import 'dart:async';
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import 'dart:math';
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import '../models/pronunciation_item.dart';
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/// 语音识别和评分服务
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class SpeechRecognitionService {
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static final SpeechRecognitionService _instance = SpeechRecognitionService._internal();
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factory SpeechRecognitionService() => _instance;
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SpeechRecognitionService._internal();
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bool _isListening = false;
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StreamController<double>? _volumeController;
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StreamController<String>? _recognitionController;
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/// 获取音量流
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Stream<double> get volumeStream => _volumeController?.stream ?? const Stream.empty();
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/// 获取识别结果流
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Stream<String> get recognitionStream => _recognitionController?.stream ?? const Stream.empty();
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/// 是否正在监听
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bool get isListening => _isListening;
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/// 开始语音识别
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Future<bool> startListening() async {
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if (_isListening) return false;
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try {
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_isListening = true;
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_volumeController = StreamController<double>.broadcast();
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_recognitionController = StreamController<String>.broadcast();
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// TODO: 实现真实的语音识别
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// 这里应该调用语音识别API，如Google Speech-to-Text、百度语音识别等
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// 模拟音量变化
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_simulateVolumeChanges();
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return true;
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} catch (e) {
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_isListening = false;
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return false;
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}
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}
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/// 停止语音识别
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Future<void> stopListening() async {
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if (!_isListening) return;
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_isListening = false;
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await _volumeController?.close();
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await _recognitionController?.close();
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_volumeController = null;
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_recognitionController = null;
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}
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/// 分析发音并评分
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Future<PronunciationResult> analyzePronunciation(
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String recordedText,
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PronunciationItem targetItem,
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) async {
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// TODO: 实现真实的发音分析
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// 这里应该调用发音评估API，如科大讯飞语音评测、腾讯云语音评测等
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// 模拟分析过程
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await Future.delayed(const Duration(milliseconds: 1500));
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return _simulateAnalysis(recordedText, targetItem);
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}
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/// 模拟音量变化
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void _simulateVolumeChanges() {
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Timer.periodic(const Duration(milliseconds: 100), (timer) {
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if (!_isListening) {
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timer.cancel();
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return;
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}
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// 生成随机音量值
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final volume = Random().nextDouble() * 0.8 + 0.1;
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_volumeController?.add(volume);
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});
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}
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/// 模拟发音分析
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PronunciationResult _simulateAnalysis(String recordedText, PronunciationItem targetItem) {
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final random = Random();
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// 基础分数
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double baseScore = 60.0 + random.nextDouble() * 30;
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// 根据文本相似度调整分数
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final similarity = _calculateSimilarity(recordedText.toLowerCase(), targetItem.text.toLowerCase());
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final adjustedScore = baseScore + (similarity * 20);
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// 确保分数在合理范围内
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final finalScore = adjustedScore.clamp(0.0, 100.0);
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return PronunciationResult(
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score: finalScore,
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accuracy: _getAccuracyLevel(finalScore),
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feedback: _generateFeedback(finalScore, targetItem),
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detailedAnalysis: _generateDetailedAnalysis(finalScore, targetItem),
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suggestions: _generateSuggestions(finalScore, targetItem),
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recognizedText: recordedText,
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);
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}
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/// 计算文本相似度
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double _calculateSimilarity(String text1, String text2) {
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if (text1 == text2) return 1.0;
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final words1 = text1.split(' ');
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final words2 = text2.split(' ');
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int matches = 0;
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final maxLength = max(words1.length, words2.length);
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for (int i = 0; i < min(words1.length, words2.length); i++) {
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if (words1[i] == words2[i]) {
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matches++;
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}
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}
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return matches / maxLength;
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}
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/// 获取准确度等级
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AccuracyLevel _getAccuracyLevel(double score) {
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if (score >= 90) return AccuracyLevel.excellent;
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if (score >= 80) return AccuracyLevel.good;
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if (score >= 70) return AccuracyLevel.fair;
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if (score >= 60) return AccuracyLevel.needsImprovement;
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return AccuracyLevel.poor;
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}
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/// 生成反馈
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String _generateFeedback(double score, PronunciationItem item) {
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if (score >= 90) {
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return '发音非常标准！语调和节奏都很自然。';
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} else if (score >= 80) {
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return '发音很好，只需要在个别音素上稍作调整。';
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} else if (score >= 70) {
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return '发音基本正确，建议多练习重音和语调。';
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} else if (score >= 60) {
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return '发音需要改进，请注意音素的准确性。';
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} else {
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return '发音需要大幅改进，建议从基础音素开始练习。';
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}
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}
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/// 生成详细分析
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Map<String, double> _generateDetailedAnalysis(double score, PronunciationItem item) {
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final random = Random();
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final baseVariation = (score - 70) / 30; // 基于总分的变化
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return {
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'音素准确度': (70 + baseVariation * 20 + random.nextDouble() * 10).clamp(0, 100),
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'语调自然度': (65 + baseVariation * 25 + random.nextDouble() * 15).clamp(0, 100),
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'语速适中度': (75 + baseVariation * 15 + random.nextDouble() * 10).clamp(0, 100),
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'重音正确度': (70 + baseVariation * 20 + random.nextDouble() * 10).clamp(0, 100),
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'流畅度': (60 + baseVariation * 30 + random.nextDouble() * 15).clamp(0, 100),
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};
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}
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/// 生成改进建议
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List<String> _generateSuggestions(double score, PronunciationItem item) {
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List<String> suggestions = [];
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if (score < 80) {
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suggestions.addAll([
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'多听标准发音，模仿语调变化',
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'注意重音位置，突出重读音节',
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]);
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}
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if (score < 70) {
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suggestions.addAll([
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'放慢语速，确保每个音素清晰',
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'练习困难音素的发音方法',
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]);
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}
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if (score < 60) {
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suggestions.addAll([
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'从基础音标开始系统学习',
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'使用镜子观察口型变化',
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]);
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}
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// 根据练习类型添加特定建议
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switch (item.type) {
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case PronunciationType.word:
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suggestions.add('分解单词，逐个音节练习');
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break;
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case PronunciationType.sentence:
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suggestions.add('注意句子的语调起伏和停顿');
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break;
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case PronunciationType.phrase:
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suggestions.add('练习短语内部的连读现象');
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break;
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case PronunciationType.phoneme:
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suggestions.add('重点练习该音素的舌位和口型');
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break;
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}
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return suggestions;
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}
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/// 获取发音提示
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List<String> getPronunciationTips(PronunciationItem item) {
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return item.tips;
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}
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/// 播放标准发音
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Future<void> playStandardAudio(String audioUrl) async {
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// TODO: 实现音频播放功能
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// 这里应该使用音频播放插件，如audioplayers
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// 模拟播放时间
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await Future.delayed(const Duration(seconds: 2));
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}
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/// 检查麦克风权限
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Future<bool> checkMicrophonePermission() async {
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// TODO: 实现权限检查
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// 这里应该使用权限插件，如permission_handler
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// 模拟权限检查
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return true;
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}
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/// 请求麦克风权限
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Future<bool> requestMicrophonePermission() async {
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// TODO: 实现权限请求
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// 这里应该使用权限插件，如permission_handler
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// 模拟权限请求
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return true;
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}
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}
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/// 发音分析结果
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class PronunciationResult {
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final double score;
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final AccuracyLevel accuracy;
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final String feedback;
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final Map<String, double> detailedAnalysis;
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final List<String> suggestions;
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final String recognizedText;
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PronunciationResult({
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required this.score,
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required this.accuracy,
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required this.feedback,
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required this.detailedAnalysis,
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required this.suggestions,
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required this.recognizedText,
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});
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}
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/// 准确度等级
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enum AccuracyLevel {
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excellent,
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good,
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fair,
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needsImprovement,
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poor,
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}
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extension AccuracyLevelExtension on AccuracyLevel {
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String get displayName {
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switch (this) {
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case AccuracyLevel.excellent:
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return '优秀';
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case AccuracyLevel.good:
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return '良好';
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case AccuracyLevel.fair:
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return '一般';
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case AccuracyLevel.needsImprovement:
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return '需要改进';
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case AccuracyLevel.poor:
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return '较差';
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}
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}
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String get description {
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switch (this) {
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case AccuracyLevel.excellent:
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return '发音非常标准，语调自然';
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case AccuracyLevel.good:
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return '发音准确，略有改进空间';
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case AccuracyLevel.fair:
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return '发音基本正确，需要练习';
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case AccuracyLevel.needsImprovement:
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return '发音有明显问题，需要改进';
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case AccuracyLevel.poor:
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return '发音问题较多，需要系统练习';
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}
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}
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String get emoji {
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switch (this) {
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case AccuracyLevel.excellent:
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return '🌟';
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case AccuracyLevel.good:
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return '👍';
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case AccuracyLevel.fair:
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return '👌';
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case AccuracyLevel.needsImprovement:
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return '📈';
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case AccuracyLevel.poor:
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return '💪';
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}
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}
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} |