鸿蒙数学公式识别计算器开发指南 原创

鸿蒙数学公式识别计算器开发指南

一、系统架构设计

基于HarmonyOS的AI能力和分布式技术，我们设计了一套数学公式识别计算系统，主要功能包括：
公式拍照：使用设备相机拍摄手写数学公式

AI识别：识别数学公式并转换为可计算格式

实时计算：计算识别出的数学公式结果

多设备同步：跨设备同步计算记录和历史

步骤展示：展示详细计算步骤

!https://example.com/harmony-math-formula-arch.png

二、核心代码实现
相机服务管理

// FormulaCameraService.ets
import camera from ‘@ohos.multimedia.camera’;
import image from ‘@ohos.multimedia.image’;

class FormulaCameraService {
private static instance: FormulaCameraService;
private cameraManager: camera.CameraManager;
private cameraInput: camera.CameraInput | null = null;
private previewOutput: camera.PreviewOutput | null = null;
private photoOutput: camera.PhotoOutput | null = null;

private constructor() {
this.cameraManager = camera.getCameraManager();
public static getInstance(): FormulaCameraService {

if (!FormulaCameraService.instance) {
  FormulaCameraService.instance = new FormulaCameraService();

return FormulaCameraService.instance;

public async initCamera(previewSurfaceId: string): Promise<void> {

const cameras = this.cameraManager.getSupportedCameras();
if (cameras.length === 0) {
  throw new Error('No camera available');

this.cameraInput = this.cameraManager.createCameraInput(cameras[0]);

await this.cameraInput.open();

const previewProfile = this.cameraManager.getSupportedOutputCapability(
  cameras[0],
  camera.ProfileMode.PROFILE_MODE_DEFAULT
).previewProfiles[0];

this.previewOutput = this.cameraManager.createPreviewOutput(
  previewProfile,
  previewSurfaceId
);

const photoProfiles = this.cameraManager.getSupportedOutputCapability(
  cameras[0],
  camera.ProfileMode.PROFILE_MODE_DEFAULT
).photoProfiles;

this.photoOutput = this.cameraManager.createPhotoOutput(
  photoProfiles[0]
);

public async takeFormulaPhoto(): Promise<image.Image> {

if (!this.photoOutput) {
  throw new Error('Photo output not initialized');

const photoSettings = {

  quality: camera.QualityLevel.QUALITY_LEVEL_HIGH,
  rotation: camera.ImageRotation.ROTATION_0
};

return new Promise((resolve, reject) => {
  this.photoOutput!.capture(photoSettings, (err, image) => {
    if (err) {
      reject(err);

else {

      resolve(image);

});

});

}

export const formulaCameraService = FormulaCameraService.getInstance();

公式识别服务

// FormulaRecognitionService.ets
import image from ‘@ohos.multimedia.image’;
import http from ‘@ohos.net.http’;

class FormulaRecognitionService {
private static instance: FormulaRecognitionService;
private httpClient: http.HttpRequest;
private apiKey = ‘YOUR_MATH_API_KEY’;

private constructor() {
this.httpClient = http.createHttp();
public static getInstance(): FormulaRecognitionService {

if (!FormulaRecognitionService.instance) {
  FormulaRecognitionService.instance = new FormulaRecognitionService();

return FormulaRecognitionService.instance;

public async recognizeFormula(image: image.Image): Promise<FormulaResult> {

const formData = new FormData();
formData.append('image', new Blob([image], { type: 'image/jpeg' }));
formData.append('api_key', this.apiKey);

return new Promise((resolve, reject) => {
  this.httpClient.request(
    'https://math-api.example.com/recognize',

method: ‘POST’,

      header: { 'Content-Type': 'multipart/form-data' },
      extraData: formData
    },
    (err, data) => {
      if (err) {
        reject(err);

else {

        const result = JSON.parse(data.result);
        resolve(this.processFormulaResult(result));

}

  );
});

private processFormulaResult(rawData: any): FormulaResult {

return {
  latex: rawData.latex || '',
  mathml: rawData.mathml || '',
  confidence: rawData.confidence || 0,
  recognizedText: rawData.text || '',
  boundingBoxes: rawData.boundingBoxes || []
};

}

export const formulaRecognitionService = FormulaRecognitionService.getInstance();

数学计算引擎

// MathEngineService.ets
class MathEngineService {
private static instance: MathEngineService;

private constructor() {}

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

public evaluateExpression(expression: string): CalculationResult {

try {
  // 简单表达式求值（实际应用中应使用更安全的数学解析库）
  const result = this.safeEval(expression);
  return {
    success: true,
    result: result,
    steps: this.generateCalculationSteps(expression, result),
    error: null
  };

catch (error) {

  return {
    success: false,
    result: null,
    steps: [],
    error: error.message
  };

}

private safeEval(expr: string): number {
// 替换常见数学函数和常量
expr = expr
.replace(/sqrt(/g, ‘Math.sqrt(’)
.replace(/sin(/g, ‘Math.sin(’)
.replace(/cos(/g, ‘Math.cos(’)
.replace(/tan(/g, ‘Math.tan(’)
.replace(/log(/g, ‘Math.log10(’)
.replace(/ln(/g, ‘Math.log(’)
.replace(/pi/g, ‘Math.PI’)
.replace(/e/g, ‘Math.E’);

// 简单验证表达式安全性
if (/[a-df-zA-DF-Z]/.test(expr.replace(/Math\./g, ''))) {
  throw new Error('表达式包含不安全字符');

// 使用Function构造器避免直接使用eval

return new Function(return ${expr})();

private generateCalculationSteps(expr: string, result: number): CalculationStep[] {

const steps: CalculationStep[] = [];

// 解析步骤示例（实际应用中应使用更复杂的解析器）
steps.push({
  description: 原始表达式: ${expr},
  expression: expr
});

// 处理括号
if (expr.includes('(')) {
  const simplified = expr.replace(/\(([^()]+)\)/g, (match, group) => {
    const value = this.safeEval(group);
    steps.push({
      description: 计算括号内表达式: {group} = {value},
      expression: expr.replace(match, value.toString())
    });
    return value.toString();
  });
  
  steps.push({
    description: '简化后表达式',
    expression: simplified
  });

// 最终结果

steps.push({
  description: 最终结果: ${result},
  expression: result.toString()
});

return steps;

}

export const mathEngineService = MathEngineService.getInstance();

多设备同步服务

// CalculationSyncService.ets
import distributedData from ‘@ohos.data.distributedData’;
import deviceManager from ‘@ohos.distributedHardware.deviceManager’;

class CalculationSyncService {
private static instance: CalculationSyncService;
private kvManager: distributedData.KVManager;
private kvStore: distributedData.KVStore;

private constructor() {
this.initKVStore();
private async initKVStore(): Promise<void> {

const config = {
  bundleName: 'com.example.mathCalculator',
  userInfo: { userId: 'currentUser' }
};

this.kvManager = distributedData.createKVManager(config);
this.kvStore = await this.kvManager.getKVStore('calculation_store', {
  createIfMissing: true
});

this.kvStore.on('dataChange', (data) => {
  this.handleRemoteUpdate(data);
});

public static getInstance(): CalculationSyncService {

if (!CalculationSyncService.instance) {
  CalculationSyncService.instance = new CalculationSyncService();

return CalculationSyncService.instance;

public async syncCalculation(record: CalculationRecord): Promise<void> {

await this.kvStore.put(calc_${record.id}, JSON.stringify(record));

public async getCalculationHistory(): Promise<CalculationRecord[]> {

const entries = await this.kvStore.getEntries('calc_');
return Array.from(entries)
  .map(([_, value]) => JSON.parse(value))
  .sort((a, b) => b.timestamp - a.timestamp);

public async syncFavoriteFormula(formula: FavoriteFormula): Promise<void> {

await this.kvStore.put(fav_${formula.id}, JSON.stringify(formula));

public async getFavoriteFormulas(): Promise<FavoriteFormula[]> {

const entries = await this.kvStore.getEntries('fav_');
return Array.from(entries)
  .map(([_, value]) => JSON.parse(value))
  .sort((a, b) => b.lastUsed - a.lastUsed);

private handleRemoteUpdate(data: distributedData.ChangeInfo): void {

if (data.deviceId === deviceInfo.deviceId) return;

const key = data.key as string;
if (key.startsWith('calc_')) {
  const record = JSON.parse(data.value);
  EventBus.emit('calculationUpdated', record);

else if (key.startsWith(‘fav_’)) {

  const formula = JSON.parse(data.value);
  EventBus.emit('favoriteFormulaUpdated', formula);

}

export const calculationSyncService = CalculationSyncService.getInstance();

三、主界面实现
公式识别界面

// FormulaCameraView.ets
@Component
struct FormulaCameraView {
@State previewSurfaceId: string = ‘’;
@State capturedImage: image.Image | null = null;
@State isRecognizing: boolean = false;
@State calculationResult: CalculationResult | null = null;

aboutToAppear() {
this.initCamera();
build() {

Stack() {
  // 相机预览
  XComponent({
    id: 'formulaCameraPreview',
    type: 'surface',
    libraryname: 'libcamera.so',
    controller: this.previewController
  })
  .onLoad(() => {
    this.previewSurfaceId = this.previewController.getXComponentSurfaceId();
    formulaCameraService.initCamera(this.previewSurfaceId);
  })
  .width('100%')
  .height('100%')
  
  // 网格辅助线
  Column() {
    ForEach([1, 2, 3, 4, 5], () => {
      Divider()
        .strokeWidth(1)
        .color('#FFFFFF80')
        .margin(8)
    })

.width(‘100%’)

  .height('100%')
  .justifyContent(FlexAlign.SpaceAround)
  
  // 拍照按钮
  Button('识别公式')
    .onClick(() => this.captureAndRecognize())
    .position({ x: '50%', y: '90%' })
  
  // 识别状态
  if (this.isRecognizing) {
    LoadingProgress()
      .position({ x: '50%', y: '50%' })

// 计算结果

  if (this.calculationResult) {
    CalculationResultView({ result: this.calculationResult })
      .position({ x: '50%', y: '30%' })

}

private async captureAndRecognize(): Promise<void> {

this.isRecognizing = true;
this.capturedImage = await formulaCameraService.takeFormulaPhoto();
const formulaResult = await formulaRecognitionService.recognizeFormula(this.capturedImage);

// 计算表达式
this.calculationResult = mathEngineService.evaluateExpression(formulaResult.recognizedText);

// 保存计算记录
const record: CalculationRecord = {
  id: generateId(),
  formula: formulaResult.recognizedText,
  result: this.calculationResult.success ? this.calculationResult.result : null,
  timestamp: Date.now(),
  image: this.capturedImage,
  steps: this.calculationResult.steps,
  isFavorite: false
};

await calculationSyncService.syncCalculation(record);
EventBus.emit('calculationCompleted', record);
this.isRecognizing = false;

}

function generateId(): string {
return Math.random().toString(36).substring(2) + Date.now().toString(36);

计算历史界面

// CalculationHistoryView.ets
@Component
struct CalculationHistoryView {
@State history: CalculationRecord[] = [];
@State favorites: FavoriteFormula[] = [];

aboutToAppear() {
this.loadHistory();
EventBus.on(‘calculationUpdated’, () => this.loadHistory());
EventBus.on(‘favoriteFormulaUpdated’, () => this.loadFavorites());
build() {

Column() {
  Text('计算历史')
    .fontSize(24)
    .fontWeight(FontWeight.Bold)
    .margin({ top: 16 })
  
  if (this.history.length === 0) {
    Text('暂无计算记录')
      .fontSize(16)
      .margin({ top: 32 })

else {

    List({ space: 10 }) {
      ForEach(this.history, (record) => {
        ListItem() {
          CalculationRecordItem({ record })

})

.layoutWeight(1)

}

.padding(16)

private async loadHistory(): Promise<void> {

this.history = await calculationSyncService.getCalculationHistory();

private async loadFavorites(): Promise<void> {

this.favorites = await calculationSyncService.getFavoriteFormulas();

}

@Component
struct CalculationRecordItem {
private record: CalculationRecord;

build() {
Row() {
Column() {
Text(this.record.formula)
.fontSize(18)
.fontWeight(FontWeight.Bold)

    if (this.record.result !== null) {
      Text(= ${this.record.result})
        .fontSize(16)
        .fontColor('#4CAF50')
        .margin({ top: 4 })

else {

      Text('计算失败')
        .fontSize(16)
        .fontColor('#FF5722')
        .margin({ top: 4 })

Text(formatDate(this.record.timestamp))

      .fontSize(12)
      .fontColor('#666666')
      .margin({ top: 8 })

.layoutWeight(1)

  Button(this.record.isFavorite ? '★' : '☆')
    .onClick(() => this.toggleFavorite())
    .fontSize(20)
    .fontColor(this.record.isFavorite ? '#FFC107' : '#999999')

.padding(12)

.onClick(() => {
  EventBus.emit('showCalculationDetail', this.record);
})

private async toggleFavorite(): Promise<void> {

const favorite: FavoriteFormula = {
  id: this.record.id,
  formula: this.record.formula,
  result: this.record.result,
  lastUsed: Date.now()
};

await calculationSyncService.syncFavoriteFormula(favorite);

}

function formatDate(timestamp: number): string {
const date = new Date(timestamp);
return {date.getFullYear()}-{date.getMonth() + 1}-{date.getDate()} {date.getHours()}:${date.getMinutes()};

计算详情界面

// CalculationDetailView.ets
@Component
struct CalculationDetailView {
@State record: CalculationRecord | null = null;

aboutToAppear() {
EventBus.on(‘showCalculationDetail’, (record) => {
this.record = record;
});
build() {

Column() {
  if (this.record) {
    Scroll() {
      Column() {
        // 公式图片
        Image(this.record.image)
          .width('100%')
          .aspectRatio(1)
          .objectFit(ImageFit.Contain)
          .backgroundColor('#F5F5F5')
        
        // 公式文本
        Text(this.record.formula)
          .fontSize(24)
          .fontWeight(FontWeight.Bold)
          .margin({ top: 16 })
        
        // 计算结果
        if (this.record.result !== null) {
          Text(= ${this.record.result})
            .fontSize(32)
            .fontColor('#4CAF50')
            .margin({ top: 8 })

else {

          Text('计算失败')
            .fontSize(24)
            .fontColor('#FF5722')
            .margin({ top: 8 })

// 计算步骤

        Text('计算步骤')
          .fontSize(20)
          .fontWeight(FontWeight.Bold)
          .margin({ top: 24 })
        
        if (this.record.steps && this.record.steps.length > 0) {
          ForEach(this.record.steps, (step) => {
            Column() {
              Text(step.description)
                .fontSize(16)
              
              Text(step.expression)
                .fontSize(14)
                .fontColor('#666666')
                .margin({ top: 4 })
              
              Divider()
                .margin({ top: 8 })

.margin({ top: 8 })

          })

else {

          Text('无详细计算步骤')
            .fontSize(16)
            .margin({ top: 8 })

// 操作按钮

        Row() {
          Button('重新计算')
            .onClick(() => this.recalculate())
          
          Button('分享')
            .onClick(() => this.shareCalculation())
            .margin({ left: 16 })

.margin({ top: 24 })

        .justifyContent(FlexAlign.Center)

.padding(16)

}

}

private async recalculate(): Promise<void> {
if (!this.record) return;

const result = mathEngineService.evaluateExpression(this.record.formula);
this.record.result = result.success ? result.result : null;
this.record.steps = result.steps;

await calculationSyncService.syncCalculation(this.record);

private async shareCalculation(): Promise<void> {

if (!this.record) return;

const shareData = {
  formula: this.record.formula,
  result: this.record.result,
  steps: this.record.steps.map(s => {s.description}: {s.expression}).join('\n')
};

await share.share({
  type: 'text/plain',
  data: JSON.stringify(shareData)
});

}

四、高级功能实现
多设备协同计算

// CollaborativeCalculationService.ets
class CollaborativeCalculationService {
private static instance: CollaborativeCalculationService;

private constructor() {}

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

public async startGroupCalculation(groupId: string): Promise<void> {

const devices = await deviceManager.getTrustedDevices();
await Promise.all(devices.map(device => 
  this.inviteDeviceToGroup(device.id, groupId)
));

private async inviteDeviceToGroup(deviceId: string, groupId: string): Promise<void> {

const ability = await featureAbility.startAbility({
  bundleName: 'com.example.mathCalculator',
  abilityName: 'MathGroupAbility',
  deviceId
});

await ability.call({
  method: 'joinGroup',
  parameters: [groupId]
});

public async shareCalculation(record: CalculationRecord, groupId: string): Promise<void> {

await calculationSyncService.syncCalculation(record);

const devices = await deviceManager.getTrustedDevices();
await Promise.all(devices.map(device => 
  this.sendCalculationToDevice(device.id, record, groupId)
));

private async sendCalculationToDevice(deviceId: string, record: CalculationRecord, groupId: string): Promise<void> {

const ability = await featureAbility.startAbility({
  bundleName: 'com.example.mathCalculator',
  abilityName: 'MathGroupAbility',
  deviceId
});

await ability.call({
  method: 'receiveCalculation',
  parameters: [record, groupId]
});

}

export const collaborativeCalculationService = CollaborativeCalculationService.getInstance();

公式学习模式

// FormulaLearningService.ets
class FormulaLearningService {
private static instance: FormulaLearningService;

private constructor() {}

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

public explainFormula(formula: string): FormulaExplanation {

const explanation: FormulaExplanation = {
  formula: formula,
  components: this.extractComponents(formula),
  relatedFormulas: this.findRelatedFormulas(formula),
  applications: this.findApplications(formula),
  difficulty: this.estimateDifficulty(formula)
};

return explanation;

private extractComponents(formula: string): FormulaComponent[] {

const components: FormulaComponent[] = [];

// 提取变量
const variables = formula.match(/[a-zA-Z]+/g) || [];
variables.forEach(v => {
  if (!components.some(c => c.name === v)) {
    components.push({
      type: 'variable',
      name: v,
      description: 变量 ${v}
    });

});

// 提取运算符
const operators = formula.match(/[\+\-\*/^√]/g) || [];
operators.forEach(op => {
  components.push({
    type: 'operator',
    name: op,
    description: this.getOperatorDescription(op)
  });
});

// 提取函数
const functions = formula.match(/\b(sincos tan log ln sqrt)\b/g)

| [];
functions.forEach(fn => {
components.push({
type: ‘function’,
name: fn,
description: this.getFunctionDescription(fn)
});
});

return components;

private getOperatorDescription(op: string): string {

const descriptions: Record<string, string> = {
  '+': '加法运算符',
  '-': '减法运算符',
  '*': '乘法运算符',
  '/': '除法运算符',
  '^': '指数运算符',
  '√': '平方根运算符'
};
return descriptions[op] || '运算符';

private getFunctionDescription(fn: string): string {

const descriptions: Record<string, string> = {
  'sin': '正弦函数',
  'cos': '余弦函数',
  'tan': '正切函数',
  'log': '常用对数(以10为底)',
  'ln': '自然对数(以e为底)',
  'sqrt': '平方根函数'
};
return descriptions[fn] || '数学函数';

private findRelatedFormulas(formula: string): string[] {

// 简化示例，实际应用中应使用知识图谱
if (formula.includes('sin') || formula.includes('cos')) {
  return ['三角函数恒等式', '欧拉公式'];

if (formula.includes(‘^’)) {

  return ['指数法则', '对数公式'];

return [‘基本算术运算’];

private findApplications(formula: string): string[] {

// 简化示例
if (formula.includes('sin') || formula.includes('cos')) {
  return ['波动分析', '信号处理', '交流电路'];

if (formula.includes(‘^’)) {

  return ['复利计算', '指数增长模型'];

return [‘日常计算’, ‘财务计算’];

private estimateDifficulty(formula: string): number {

// 简单难度评估
let score = 0;

if (/[a-zA-Z]/.test(formula)) score += 1; // 有变量
if (/[\+\-]/.test(formula)) score += 1;
if (/[\*/]/.test(formula)) score += 2;
if (/\^/.test(formula)) score += 3;
if (/.+/.test(formula)) score += 2; // 有括号
if (/\b(sincos tan log ln

sqrt)\b/.test(formula)) score += 3;

return Math.min(5, score); // 最高难度为5

}

export const formulaLearningService = FormulaLearningService.getInstance();

智能计算提醒

// MathReminderService.ets
import reminderAgent from ‘@ohos.reminderAgent’;

class MathReminderService {
private static instance: MathReminderService;

private constructor() {}

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

public async schedulePracticeReminder(time: string): Promise<void> {

const [hours, minutes] = time.split(':').map(Number);
const reminderTime = new Date();
reminderTime.setHours(hours, minutes, 0, 0);

const reminderRequest: reminderAgent.ReminderRequest = {
  reminderType: reminderAgent.ReminderType.REMINDER_TYPE_TIMER,
  actionButton: [{ title: '已完成' }, { title: '稍后提醒' }],
  wantAgent: {
    pkgName: 'com.example.mathCalculator',
    abilityName: 'PracticeReminderAbility'
  },
  ringDuration: 60,
  snoozeTimes: 2,
  triggerTime: reminderTime.getTime(),
  repeatInterval: 24  60  60 * 1000, // 每天重复
  title: '数学练习时间',
  content: '记得练习数学公式计算哦！',
  expiredContent: "练习提醒已过期"
};

await reminderAgent.publishReminder(reminderRequest);

public async scheduleFormulaReview(formula: string, intervalDays: number): Promise<void> {

const reminderRequest: reminderAgent.ReminderRequest = {
  reminderType: reminderAgent.ReminderType.REMINDER_TYPE_TIMER,
  actionButton: [{ title: '已复习' }],
  wantAgent: {
    pkgName: 'com.example.mathCalculator',
    abilityName: 'FormulaReviewAbility'
  },
  triggerTime: Date.now() + intervalDays  24  60  60  1000,
  title: '公式复习提醒',
  content: 该复习公式: ${formula},
  expiredContent: "复习提醒已过期"
};

await reminderAgent.publishReminder(reminderRequest);

public async cancelAllReminders(): Promise<void> {

const reminders = await reminderAgent.getValidReminders();
await Promise.all(reminders.map(rem => 
  reminderAgent.cancelReminder(rem.id)
));

}

export const mathReminderService = MathReminderService.getInstance();

五、总结

本数学公式识别计算器实现了以下核心价值：
精准识别：利用AI技术准确识别手写数学公式

实时计算：即时计算识别出的数学表达式

步骤展示：详细展示计算步骤帮助学习

多设备协同：支持跨设备同步计算记录

学习辅助：提供公式解释和相关知识

扩展方向：
增加图形计算功能

开发数学题库练习模式

集成在线数学学习资源

增加语音输入和朗读功能

注意事项：
需要申请ohos.permission.CAMERA权限

公式识别准确率受书写清晰度影响

复杂表达式可能需要手动修正

多设备协同需保持网络连接

数学计算功能有限，专业用途请使用专业数学软件