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鸿蒙数学公式识别计算器开发指南 原创
进修的泡芙
发布于 2025-6-22 16:54
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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
©著作权归作者所有，如需转载，请注明出处，否则将追究法律责任
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