鸿蒙AR儿童识字卡应用开发指南

一、系统架构设计

基于HarmonyOS的AR能力和AI技术，我们设计了一套AR儿童识字系统，主要功能包括：

1. ​​卡片识别​​：通过摄像头识别识字卡片
2. ​​AR渲染​​：在卡片上叠加3D模型和动画
3. ​​语音交互​​：支持语音朗读和互动
4. ​​多设备协同​​：跨设备同步学习进度
5. ​​学习记录​​：跟踪儿童学习情况

https://example.com/harmony-ar-literacy-arch.png

二、核心代码实现

1. AR渲染服务

// ARRenderService.ets
import xComponent from '@ohos.xComponent';
import arEngine from '@ohos.arEngine';

class ARRenderService {
  private static instance: ARRenderService;
  private arSession: arEngine.ARSession | null = null;
  private xComponent: xComponent.XComponent | null = null;
  private isTracking: boolean = false;
  
  private constructor() {}

  public static getInstance(): ARRenderService {
    if (!ARRenderService.instance) {
      ARRenderService.instance = new ARRenderService();
    }
    return ARRenderService.instance;
  }

  public async initAR(surfaceId: string): Promise<void> {
    this.arSession = await arEngine.createARSession();
    await this.arSession.init();
    
    this.xComponent = xComponent.createXComponent();
    await this.xComponent.init(surfaceId);
    
    const config: arEngine.ARConfig = {
      trackingMode: arEngine.TrackingMode.TRACKING_MODE_IMAGE,
      lightEstimationMode: arEngine.LightEstimationMode.LIGHT_ESTIMATION_MODE_AMBIENT
    };
    
    await this.arSession.configure(config);
  }

  public async load3DModel(modelId: string): Promise<void> {
    if (!this.arSession) return;
    
    const model = await this.loadModelFromResources(modelId);
    await this.arSession.add3DModel(model);
  }

  public async startTracking(): Promise<void> {
    if (!this.arSession || this.isTracking) return;
    
    await this.arSession.start();
    this.isTracking = true;
    
    // 设置帧回调
    this.arSession.on('frame', (frame) => {
      this.processARFrame(frame);
    });
  }

  public stopTracking(): void {
    if (!this.arSession || !this.isTracking) return;
    
    this.arSession.stop();
    this.isTracking = false;
  }

  private async loadModelFromResources(modelId: string): Promise<arEngine.ARModel> {
    // 简化实现，实际应从资源加载模型
    return {
      id: modelId,
      uri: `resources/models/${modelId}.glb`,
      scale: { x: 0.1, y: 0.1, z: 0.1 },
      position: { x: 0, y: 0, z: 0 }
    };
  }

  private processARFrame(frame: arEngine.ARFrame): void {
    if (!frame.images || frame.images.length === 0) return;
    
    // 处理图像帧进行卡片识别
    const image = frame.images[0];
    cardRecognitionService.recognizeCard(image).then(card => {
      if (card) {
        this.showCardContent(card);
      }
    });
  }

  private showCardContent(card: RecognizedCard): void {
    if (!this.arSession) return;
    
    // 在卡片位置显示3D模型
    this.arSession.add3DModel({
      id: `card_${card.id}`,
      uri: this.getModelForCard(card),
      position: card.position,
      rotation: card.rotation,
      scale: { x: 0.05, y: 0.05, z: 0.05 }
    });
    
    // 显示文字
    this.showTextLabel(card);
  }

  private getModelForCard(card: RecognizedCard): string {
    const modelMap: Record<string, string> = {
      'apple': 'models/fruit_apple.glb',
      'banana': 'models/fruit_banana.glb',
      'cat': 'models/animal_cat.glb',
      'dog': 'models/animal_dog.glb'
      // 更多卡片模型...
    };
    
    return modelMap[card.word] || 'models/default.glb';
  }

  private showTextLabel(card: RecognizedCard): void {
    if (!this.arSession) return;
    
    this.arSession.addTextLabel({
      id: `label_${card.id}`,
      text: card.word,
      position: {
        x: card.position.x,
        y: card.position.y + 0.1,
        z: card.position.z
      },
      color: '#FFD700',
      fontSize: 0.1,
      backgroundColor: '#00000080'
    });
  }
}

export const arRenderService = ARRenderService.getInstance();

2. 卡片识别服务

// CardRecognitionService.ets
import image from '@ohos.multimedia.image';
import objectRecognition from '@ohos.ai.objectRecognition';

class CardRecognitionService {
  private static instance: CardRecognitionService;
  private recognizer: objectRecognition.ObjectRecognizer;
  
  private constructor() {
    this.recognizer = objectRecognition.createRecognizer();
  }

  public static getInstance(): CardRecognitionService {
    if (!CardRecognitionService.instance) {
      CardRecognitionService.instance = new CardRecognitionService();
    }
    return CardRecognitionService.instance;
  }

  public async recognizeCard(image: image.Image): Promise<RecognizedCard | null> {
    const config: objectRecognition.RecognitionConfig = {
      featureType: objectRecognition.FeatureType.FEATURE_TYPE_TEXT,
      processMode: objectRecognition.ProcessMode.PROCESS_MODE_FAST
    };
    
    return new Promise((resolve, reject) => {
      this.recognizer.recognize(image, config, (err, result) => {
        if (err) {
          reject(err);
        } else {
          resolve(this.processRecognitionResult(result));
        }
      });
    });
  }

  private processRecognitionResult(rawData: any): RecognizedCard | null {
    if (!rawData || !rawData.objects || rawData.objects.length === 0) {
      return null;
    }
    
    // 找出最可能是识字卡的对象
    const card = rawData.objects.find((obj: any) => 
      obj.confidence > 0.7 && this.isLearningCard(obj.text)
    );
    
    if (!card) return null;
    
    return {
      id: generateId(),
      word: this.normalizeWord(card.text),
      confidence: card.confidence,
      position: card.position,
      rotation: card.rotation,
      timestamp: Date.now()
    };
  }

  private isLearningCard(text: string): boolean {
    const learningWords = ['苹果', '香蕉', '猫', '狗', '书', '车', '房子', '树'];
    return learningWords.includes(this.normalizeWord(text));
  }

  private normalizeWord(word: string): string {
    // 简化处理，实际可能需要更复杂的文本规范化
    return word.trim().replace(/[.!?\\-]/g, '');
  }

  public async loadCardDatabase(): Promise<void> {
    const cards = await this.getDefaultCards();
    await this.recognizer.setDatabase(cards);
  }

  private async getDefaultCards(): Promise<LearningCard[]> {
    // 简化实现，实际应从资源或网络加载
    return [
      { word: '苹果', image: 'cards/apple.png', model: 'fruit_apple' },
      { word: '香蕉', image: 'cards/banana.png', model: 'fruit_banana' },
      { word: '猫', image: 'cards/cat.png', model: 'animal_cat' },
      { word: '狗', image: 'cards/dog.png', model: 'animal_dog' }
      // 更多卡片...
    ];
  }
}

export const cardRecognitionService = CardRecognitionService.getInstance();

3. 学习进度服务

// LearningProgressService.ets
import distributedData from '@ohos.data.distributedData';

class LearningProgressService {
  private static instance: LearningProgressService;
  private kvManager: distributedData.KVManager;
  private kvStore: distributedData.KVStore;
  
  private constructor() {
    this.initKVStore();
  }

  private async initKVStore(): Promise<void> {
    const config = {
      bundleName: 'com.example.arLiteracy',
      userInfo: { userId: 'currentChild' }
    };
    
    this.kvManager = distributedData.createKVManager(config);
    this.kvStore = await this.kvManager.getKVStore('learning_progress', {
      createIfMissing: true
    });
    
    this.kvStore.on('dataChange', (data) => {
      this.handleRemoteUpdate(data);
    });
  }

  public static getInstance(): LearningProgressService {
    if (!LearningProgressService.instance) {
      LearningProgressService.instance = new LearningProgressService();
    }
    return LearningProgressService.instance;
  }

  public async recordCardLearning(card: RecognizedCard): Promise<void> {
    const progress = await this.getProgress();
    
    if (!progress.learnedCards.some(c => c.word === card.word)) {
      progress.learnedCards.push({
        word: card.word,
        firstLearned: Date.now(),
        lastReviewed: Date.now(),
        reviewCount: 1
      });
    } else {
      const learnedCard = progress.learnedCards.find(c => c.word === card.word);
      if (learnedCard) {
        learnedCard.lastReviewed = Date.now();
        learnedCard.reviewCount++;
      }
    }
    
    await this.kvStore.put('progress', JSON.stringify(progress));
  }

  public async getProgress(): Promise<LearningProgress> {
    const value = await this.kvStore.get('progress');
    return value ? JSON.parse(value) : { learnedCards: [] };
  }

  public async getLearnedWords(): Promise<string[]> {
    const progress = await this.getProgress();
    return progress.learnedCards.map(card => card.word);
  }

  public async syncProgressToDevice(deviceId: string): Promise<void> {
    const progress = await this.getProgress();
    const ability = await featureAbility.startAbility({
      bundleName: 'com.example.arLiteracy',
      abilityName: 'ProgressSyncAbility',
      deviceId
    });
    
    await ability.call({
      method: 'receiveProgress',
      parameters: [progress]
    });
  }

  private handleRemoteUpdate(data: distributedData.ChangeInfo): void {
    if (data.deviceId === deviceInfo.deviceId) return;
    
    if (data.key === 'progress') {
      const progress = JSON.parse(data.value);
      EventBus.emit('progressUpdated', progress);
    }
  }
}

export const progressService = LearningProgressService.getInstance();

三、主界面实现

1. AR识别界面

// ARCameraView.ets
@Component
struct ARCameraView {
  @State recognizedCards: RecognizedCard[] = [];
  @State currentCard: RecognizedCard | null = null;
  @State isTracking: boolean = false;
  @State surfaceId: string = '';
  
  aboutToAppear() {
    this.initAR();
  }

  build() {
    Stack() {
      // AR相机预览
      XComponent({
        id: 'arCameraPreview',
        type: 'surface',
        libraryname: 'libar.so',
        controller: this.arController
      })
      .onLoad(() => {
        this.surfaceId = this.arController.getXComponentSurfaceId();
        arRenderService.initAR(this.surfaceId);
      })
      .width('100%')
      .height('100%')
      
      // 识别到的卡片列表
      if (this.recognizedCards.length > 0) {
        Position() {
          Column() {
            ForEach(this.recognizedCards, (card) => {
              CardItem({ card })
                .onClick(() => this.focusCard(card))
            })
          }
          .position({ x: '80%', y: '20%' })
        }
      }
      
      // 当前卡片内容
      if (this.currentCard) {
        Position() {
          CardDetailView({ card: this.currentCard })
            .position({ x: '50%', y: '80%' })
        }
      }
      
      // 控制按钮
      Position() {
        Button(this.isTracking ? '停止识别' : '开始识别')
          .onClick(() => this.toggleTracking())
          .position({ x: '50%', y: '90%' })
      }
    }
  }

  private async initAR(): Promise<void> {
    await arRenderService.initAR(this.surfaceId);
    await cardRecognitionService.loadCardDatabase();
    
    EventBus.on('cardRecognized', (card) => {
      this.onCardRecognized(card);
    });
  }

  private toggleTracking(): void {
    if (this.isTracking) {
      arRenderService.stopTracking();
    } else {
      arRenderService.startTracking();
    }
    
    this.isTracking = !this.isTracking;
  }

  private onCardRecognized(card: RecognizedCard): void {
    // 去重
    if (!this.recognizedCards.some(c => c.word === card.word)) {
      this.recognizedCards = [...this.recognizedCards, card];
    }
    
    // 记录学习进度
    progressService.recordCardLearning(card);
    
    // 朗读单词
    ttsService.speak(card.word);
  }

  private focusCard(card: RecognizedCard): void {
    this.currentCard = card;
    arRenderService.focusOnCard(card);
  }
}

@Component
struct CardItem {
  private card: RecognizedCard;
  
  build() {
    Column() {
      Image(this.getCardImage())
        .width(80)
        .height(80)
        .borderRadius(8)
      
      Text(this.card.word)
        .fontSize(16)
        .margin({ top: 4 })
    }
    .padding(8)
    .backgroundColor('#FFFFFF')
    .borderRadius(8)
    .shadow({ radius: 4, color: '#00000020' })
  }

  private getCardImage(): string {
    const imageMap: Record<string, string> = {
      '苹果': 'resources/cards/apple.png',
      '香蕉': 'resources/cards/banana.png',
      '猫': 'resources/cards/cat.png',
      '狗': 'resources/cards/dog.png'
    };
    
    return imageMap[this.card.word] || 'resources/cards/default.png';
  }
}

@Component
struct CardDetailView {
  private card: RecognizedCard;
  
  build() {
    Column() {
      Text(this.card.word)
        .fontSize(24)
        .fontWeight(FontWeight.Bold)
        .fontColor('#FFD700')
      
      Text(this.getPinyin())
        .fontSize(16)
        .margin({ top: 4 })
      
      Button('朗读')
        .onClick(() => ttsService.speak(this.card.word))
        .margin({ top: 8 })
    }
    .padding(16)
    .backgroundColor('#00000080')
    .borderRadius(8)
  }

  private getPinyin(): string {
    const pinyinMap: Record<string, string> = {
      '苹果': 'píng guǒ',
      '香蕉': 'xiāng jiāo',
      '猫': 'māo',
      '狗': 'gǒu'
    };
    
    return pinyinMap[this.card.word] || '';
  }
}

2. 学习记录界面

// ProgressView.ets
@Component
struct ProgressView {
  @State progress: LearningProgress = { learnedCards: [] };
  @State selectedCategory: string = '全部';
  
  aboutToAppear() {
    this.loadProgress();
    EventBus.on('progressUpdated', () => this.loadProgress());
  }

  build() {
    Column() {
      Text('学习记录')
        .fontSize(24)
        .fontWeight(FontWeight.Bold)
        .margin({ top: 16 })
      
      // 分类筛选
      Picker({ range: this.getCategories(), selected: this.getCategoryIndex() })
        .onChange((index: number) => {
          this.selectedCategory = this.getCategories()[index];
        })
        .margin({ top: 16 })
      
      // 学习统计
      Row() {
        Text(`已学习: ${this.progress.learnedCards.length}个词语`)
          .fontSize(16)
        
        Text(`复习次数: ${this.getTotalReviews()}`)
          .fontSize(16)
          .margin({ left: 16 })
      }
      .margin({ top: 16 })
      
      // 学习日历
      LearningCalendar({ progress: this.progress })
        .margin({ top: 16 })
      
      // 已学词语列表
      if (this.progress.learnedCards.length === 0) {
        Text('还没有学习记录')
          .fontSize(16)
          .margin({ top: 32 })
      } else {
        List({ space: 10 }) {
          ForEach(this.getFilteredCards(), (card) => {
            ListItem() {
              LearnedCardItem({ card })
            }
          })
        }
        .layoutWeight(1)
      }
    }
    .padding(16)
  }

  private async loadProgress(): Promise<void> {
    this.progress = await progressService.getProgress();
  }

  private getCategories(): string[] {
    return ['全部', '水果', '动物', '物品', '其他'];
  }

  private getCategoryIndex(): number {
    return this.getCategories().indexOf(this.selectedCategory);
  }

  private getFilteredCards(): LearnedCard[] {
    const categoryMap: Record<string, string[]> = {
      '水果': ['苹果', '香蕉', '橙子', '西瓜'],
      '动物': ['猫', '狗', '鸟', '鱼'],
      '物品': ['书', '车', '房子', '树']
    };
    
    if (this.selectedCategory === '全部') {
      return this.progress.learnedCards;
    }
    
    return this.progress.learnedCards.filter(card => 
      categoryMap[this.selectedCategory]?.includes(card.word)
    );
  }

  private getTotalReviews(): number {
    return this.progress.learnedCards.reduce((sum, card) => sum + card.reviewCount, 0);
  }
}

@Component
struct LearnedCardItem {
  private card: LearnedCard;
  
  build() {
    Row() {
      Image(this.getCardImage())
        .width(60)
        .height(60)
        .borderRadius(8)
      
      Column() {
        Text(this.card.word)
          .fontSize(18)
          .fontWeight(FontWeight.Bold)
        
        Text(`复习次数: ${this.card.reviewCount}`)
          .fontSize(14)
          .fontColor('#666666')
          .margin({ top: 4 })
        
        Text(this.formatDate(this.card.lastReviewed))
          .fontSize(12)
          .fontColor('#999999')
          .margin({ top: 4 })
      }
      .margin({ left: 12 })
      .layoutWeight(1)
      
      Button('复习')
        .onClick(() => this.reviewCard())
        .width(80)
    }
    .padding(12)
  }

  private getCardImage(): string {
    const imageMap: Record<string, string> = {
      '苹果': 'resources/cards/apple.png',
      '香蕉': 'resources/cards/banana.png',
      '猫': 'resources/cards/cat.png',
      '狗': 'resources/cards/dog.png'
    };
    
    return imageMap[this.card.word] || 'resources/cards/default.png';
  }

  private formatDate(timestamp: number): string {
    const date = new Date(timestamp);
    return `${date.getMonth() + 1}月${date.getDate()}日`;
  }

  private reviewCard(): void {
    router.push({ url: `pages/ar?word=${this.card.word}` });
  }
}

@Component
struct LearningCalendar {
  private progress: LearningProgress;
  
  build() {
    Column() {
      Text('学习日历')
        .fontSize(18)
        .fontWeight(FontWeight.Bold)
        .margin({ bottom: 8 })
      
      // 简化实现，实际应显示完整日历
      Row() {
        ForEach(this.getRecentDays(), (day) => {
          Column() {
            Text(day.day.toString())
              .fontSize(14)
            
            if (day.learnedCount > 0) {
              Circle()
                .width(8)
                .height(8)
                .backgroundColor('#4CAF50')
                .margin({ top: 4 })
            }
          }
          .margin({ right: 8 })
        })
      }
    }
    .padding(16)
    .backgroundColor('#FFFFFF')
    .borderRadius(8)
  }

  private getRecentDays(): { day: number; learnedCount: number }[] {
    const now = new Date();
    const days: { day: number; learnedCount: number }[] = [];
    
    for (let i = 6; i >= 0; i--) {
      const date = new Date(now);
      date.setDate(date.getDate() - i);
      
      const day = date.getDate();
      const learnedCount = this.progress.learnedCards.filter(card => {
        const cardDate = new Date(card.lastReviewed);
        return cardDate.toDateString() === date.toDateString();
      }).length;
      
      days.push({ day, learnedCount });
    }
    
    return days;
  }
}

3. 词语详情界面

// WordDetailView.ets
@Component
struct WordDetailView {
  @State word: string = '';
  @State details: WordDetail | null = null;
  @State relatedWords: WordDetail[] = [];
  
  onInit() {
    this.word = router.getParams()?.word || '';
  }

  aboutToAppear() {
    this.loadWordDetails();
  }

  build() {
    Column() {
      if (!this.details) {
        LoadingProgress()
          .width(50)
          .height(50)
          .margin({ top: 32 })
      } else {
        Text(this.details.word)
          .fontSize(32)
          .fontWeight(FontWeight.Bold)
        
        Text(this.details.pinyin)
          .fontSize(20)
          .margin({ top: 8 })
        
        Image(this.details.image)
          .width(150)
          .height(150)
          .margin({ top: 16 })
        
        Text(this.details.definition)
          .fontSize(16)
          .margin({ top: 16 })
        
        Divider()
          .margin({ top: 16 })
        
        Text('相关词语')
          .fontSize(20)
          .fontWeight(FontWeight.Bold)
          .margin({ top: 16 })
        
        if (this.relatedWords.length === 0) {
          Text('暂无相关词语')
            .fontSize(16)
            .margin({ top: 8 })
        } else {
          Scroll({ scrollable: ScrollDirection.Horizontal }) {
            Row() {
              ForEach(this.relatedWords, (word) => {
                RelatedWordItem({ word })
                  .margin({ right: 8 })
              })
            }
            .padding(8)
          }
        }
        
        Button('AR展示')
          .onClick(() => this.showInAR())
          .margin({ top: 16 })
      }
    }
    .padding(16)
  }

  private async loadWordDetails(): Promise<void> {
    this.details = await dictionaryService.getWordDetails(this.word);
    this.relatedWords = await dictionaryService.getRelatedWords(this.word);
  }

  private showInAR(): void {
    router.push({ url: `pages/ar?word=${this.word}` });
  }
}

@Component
struct RelatedWordItem {
  private word: WordDetail;
  
  build() {
    Column() {
      Image(this.word.image)
        .width(80)
        .height(80)
        .borderRadius(8)
      
      Text(this.word.word)
        .fontSize(16)
        .margin({ top: 4 })
    }
    .padding(8)
    .backgroundColor('#FFFFFF')
    .borderRadius(8)
    .shadow({ radius: 4, color: '#00000020' })
    .onClick(() => {
      router.push({ url: `pages/word?word=${this.word.word}` });
    })
  }
}

四、高级功能实现

1. 多设备学习同步

// LearningSyncService.ets
import deviceManager from '@ohos.distributedHardware.deviceManager';

class LearningSyncService {
  private static instance: LearningSyncService;
  
  private constructor() {}

  public static getInstance(): LearningSyncService {
    if (!LearningSyncService.instance) {
      LearningSyncService.instance = new LearningSyncService();
    }
    return LearningSyncService.instance;
  }

  public async syncProgressToDevice(deviceId: string): Promise<void> {
    const progress = await progressService.getProgress();
    const ability = await featureAbility.startAbility({
      bundleName: 'com.example.arLiteracy',
      abilityName: 'ProgressSyncAbility',
      deviceId
    });
    
    await ability.call({
      method: 'receiveProgress',
      parameters: [progress]
    });
  }

  public async syncAllDataToNewDevice(deviceId: string): Promise<void> {
    const progress = await progressService.getProgress();
    const words = await dictionaryService.getAllWords();
    
    const ability = await featureAbility.startAbility({
      bundleName: 'com.example.arLiteracy',
      abilityName: 'FullSyncAbility',
      deviceId
    });
    
    await ability.call({
      method: 'receiveFullData',
      parameters: [progress, words]
    });
  }

  public async requestProgressFromDevice(deviceId: string): Promise<LearningProgress> {
    const ability = await featureAbility.startAbility({
      bundleName: 'com.example.arLiteracy',
      abilityName: 'ProgressRequestAbility',
      deviceId
    });
    
    const result = await ability.call({
      method: 'getProgress',
      parameters: []
    });
    
    return JSON.parse(result);
  }
}

export const learningSyncService = LearningSyncService.getInstance();

2. 语音交互服务

// VoiceInteractionService.ets
import voiceInteraction from '@ohos.ai.voiceInteraction';

class VoiceInteractionService {
  private static instance: VoiceInteractionService;
  private voiceAssistant: voiceInteraction.VoiceAssistant;
  private isListening: boolean = false;
  
  private constructor() {
    this.voiceAssistant = voiceInteraction.createVoiceAssistant();
  }

  public static getInstance(): VoiceInteractionService {
    if (!VoiceInteractionService.instance) {
      VoiceInteractionService.instance = new VoiceInteractionService();
    }
    return VoiceInteractionService.instance;
  }

  public async init(): Promise<void> {
    await this.voiceAssistant.init();
    await this.registerCommands();
  }

  private async registerCommands(): Promise<void> {
    const commands = [
      {
        name: 'read_word',
        patterns: ['读一下', '朗读', '这是什么'],
        action: 'read'
      },
      {
        name: 'next_word',
        patterns: ['下一个', '换一个', '继续'],
        action: 'next'
      },
      {
        name: 'spell_word',
        patterns: ['怎么拼', '拼写', '拼音'],
        action: 'spell'
      }
    ];
    
    await this.voiceAssistant.setCommands(commands);
    
    this.voiceAssistant.on('command', (command) => {
      this.handleCommand(command);
    });
  }

  public startListening(): void {
    if (this.isListening) return;
    
    this.voiceAssistant.startListening();
    this.isListening = true;
  }

  public stopListening(): void {
    if (!this.isListening) return;
    
    this.voiceAssistant.stopListening();
    this.isListening = false;
  }

  private handleCommand(command: voiceInteraction.VoiceCommand): void {
    switch (command.action) {
      case 'read':
        if (this.currentWord) {
          ttsService.speak(this.currentWord);
        }
        break;
      case 'next':
        wordService.nextWord();
        break;
      case 'spell':
        if (this.currentWord) {
          const pinyin = dictionaryService.getPinyin(this.currentWord);
          ttsService.speak(pinyin);
        }
        break;
    }
  }
}

export const voiceService = VoiceInteractionService.getInstance();

3. 文字转语音服务

// TTSService.ets
import tts from '@ohos.multimedia.tts';

class TTSService {
  private static instance: TTSService;
  private ttsEngine: tts.TTSEngine;
  
  private constructor() {
    this.ttsEngine = tts.createTTSEngine();
  }

  public static getInstance(): TTSService {
    if (!TTSService.instance) {
      TTSService.instance = new TTSService();
    }
    return TTSService.instance;
  }

  public async init(): Promise<void> {
    await this.ttsEngine.init();
    await this.ttsEngine.setVoice('child'); // 使用儿童友好的声音
  }

  public async speak(text: string): Promise<void> {
    return new Promise((resolve, reject) => {
      this.ttsEngine.speak(text, {
        onStart: () => console.log('开始朗读'),
        onFinish: () => resolve(),
        onError: (err) => reject(err)
      });
    });
  }

  public async spellWord(word: string): Promise<void> {
    const pinyin = this.getPinyin(word);
    await this.speak(pinyin);
  }

  private getPinyin(word: string): string {
    const pinyinMap: Record<string, string> = {
      '苹果': 'píng guǒ',
      '香蕉': 'xiāng jiāo',
      '猫': 'māo',
      '狗': 'gǒu'
      // 更多词语的拼音...
    };
    
    return pinyinMap[word] || word;
  }
}

export const ttsService = TTSService.getInstance();

五、总结

本AR儿童识字卡应用实现了以下核心价值：

1. ​​互动学习​​：通过AR技术让识字过程更加生动有趣
2. ​​多感官体验​​：结合视觉、听觉和触觉增强记忆
3. ​​智能识别​​：准确识别识字卡片并展示相关内容
4. ​​多设备协同​​：家长可以远程查看学习进度
5. ​​学习分析​​：记录学习情况并提供个性化建议

​​扩展方向​​：

1. 增加更多识字卡片和3D模型
2. 开发识字游戏和挑战
3. 集成家长控制功能
4. 增加手写识别练习

注意事项：
1. 需要申请ohos.permission.CAMERA权限
2. AR功能需要设备支持
3. 语音识别准确率受环境噪音影响
4. 多设备协同需保持网络连接
5. 首次使用建议完成引导设置