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Harmony os next～鸿蒙原子化服务开发实战：天气卡片开发全解析

article 2025/3/3 22:13:47

鸿蒙原子化服务开发实战：天气卡片开发全解析

一、原子化服务与HarmonyOS卡片概述

（1）原子化服务特性
HarmonyOS原子化服务具有独立入口（桌面图标/智慧搜索）、免安装、跨设备流转三大核心特性。服务卡片作为其可视化载体，支持动态数据更新与交互操作。

（2）天气卡片设计目标
开发一个支持实时天气显示、3小时预报、点击刷新的服务卡片，包含以下功能模块：

实时温湿度显示
气象图标动态展示
未来3小时预报时间轴
卡片级交互事件处理

二、开发环境搭建与技术选型

工具链配置
- DevEco Studio 3.1.1+（支持API Version 9）
- 华为模拟器/真机调试环境
- OpenHarmony SDK

技术架构

└─WeatherCard
   ├─UI层：ArkTS声明式UI
   ├─逻辑层：异步数据获取/卡片生命周期
   ├─数据层：REST API + 本地缓存
   └─卡片配置：FormAbility + JSON配置

三、服务卡片开发实践

1. 卡片模板创建

// weather_form_card.ets
@Entry
@Component
struct WeatherCard {
  @State temp: string = '--℃'
  @State forecasts: ForecastItem[] = []

  build() {
    Column() {
      // 实时天气区
      WeatherHeader({ temp: this.temp })
      
      // 预报时间轴
      WeatherTimeline({ items: this.forecasts })
      
      // 刷新按钮
      Button('刷新').onClick(() => {
        postCardAction({
          action: 'refresh',
          params: { 'force': true }
        })
      })
    }
    .cardWidth(360)
    .cardHeight(180)
  }
}

2. 数据模型定义

interface WeatherData {
  current: {
    temp: number
    humidity: number
    condition: {
      code: number
      icon: string
    }
  }
  hourly: HourlyForecast[]
}

class ForecastItem {
  time: string
  temp: number
  icon: Resource

  constructor(hourly: HourlyForecast) {
    this.time = formatTime(hourly.time)
    this.temp = hourly.temp
    this.icon = this._mapWeatherIcon(hourly.condition.code)
  }

  private _mapWeatherIcon(code: number): Resource {
    const iconMap = {
      1000: $r('app.media.sunny'),
      1003: $r('app.media.partly_cloudy'),
      // ...其他气象代码映射
    }
    return iconMap[code] || $r('app.media.unknown')
  }
}

3. 网络服务封装

// WeatherService.ts
const API_KEY = 'your_api_key'
const BASE_URL = 'https://api.weatherapi.com/v1'

export async function fetchWeather(location: string): Promise<WeatherData> {
  try {
    const response = await http.get(
      `${BASE_URL}/forecast.json?key=${API_KEY}&q=${location}&hours=3`
    )
    return response.data as WeatherData
  } catch (error) {
    Logger.error('Fetch weather failed: ' + JSON.stringify(error))
    throw new Error('天气数据获取失败')
  }
}

4. 卡片生命周期管理

// FormAbility.ts
export default class FormAbility extends FormExtensionAbility {
  onAddForm(want: Want): formBindingData.FormBindingData {
    // 初始化卡片数据
    const location = AppStorage.getOrSet('last_location', 'auto_ip')
    const data = await WeatherService.fetchWeather(location)
    return formBindingData.createFormBindingData({
      temp: `${data.current.temp}℃`,
      forecasts: data.hourly.slice(0,3)
    })
  }

  onFormEvent(formId: string, message: string): void {
    if (message === 'refresh') {
      // 处理刷新事件
      this._forceUpdateWeather(formId)
    }
  }
}

四、关键配置与特性实现

1. 卡片配置文件

// resources/base/profile/form_config.json
{
  "forms": [
    {
      "name": "weather_card",
      "description": "实时天气卡片",
      "src": "./ets/widget/WeatherCard.ets",
      "window": {
        "designWidth": 360,
        "autoDesignWidth": true
      },
      "colorMode": "auto",
      "formConfigAbility": "ability://com.example.weather.MainAbility",
      "updateEnabled": true,
      "scheduledUpdateTime": "06:00",
      "updateDuration": 1,
      "defaultDimension": "2*4",
      "supportDimensions": ["2*4", "4*4"]
    }
  ]
}

2. 动态数据更新机制

实现双缓存策略保证流畅性：

class WeatherCache {
  private static _instance: WeatherCache
  private _memoryCache: WeatherData | null = null
  private _lastUpdate: number = 0

  static getInstance(): WeatherCache {
    if (!WeatherCache._instance) {
      WeatherCache._instance = new WeatherCache()
    }
    return WeatherCache._instance
  }

  async getWeather(location: string): Promise<WeatherData> {
    if (Date.now() - this._lastUpdate < 5 * 60 * 1000) {
      return this._memoryCache!
    }
    
    const [networkData, dbData] = await Promise.allSettled([
      WeatherService.fetchWeather(location),
      Database.queryCache(location)
    ])

    if (networkData.status === 'fulfilled') {
      this._memoryCache = networkData.value
      Database.updateCache(networkData.value)
      return networkData.value
    }
    
    if (dbData.status === 'fulfilled') {
      return dbData.value
    }
    
    throw new Error('No available weather data')
  }
}

五、高级特性实现

1. 跨设备流转支持

// 设备状态监听
deviceManager.on('deviceStateChange', (event) => {
  if (event.action === 'connect') {
    this._prepareCrossDeviceData()
  }
})

private _prepareCrossDeviceData(): void {
  const weatherData = WeatherCache.getInstance().getCurrentData()
  const transferData = {
    timestamp: Date.now(),
    data: weatherData,
    format: 'weather/v1'
  }
  featureAbility.setTransferData(transferData)
}

2. 智慧搜索集成

// resources/base/profile/shortcuts_config.json
{
  "shortcuts": [
    {
      "shortcutId": "weather_search",
      "label": "天气查询",
      "icon": "$media:ic_weather",
      "intents": [
        {
          "targetBundle": "com.example.weather",
          "targetClass": "com.example.weather.MainAbility"
        }
      ]
    }
  ]
}

六、调试与优化技巧

卡片预览模式
使用DevEco Studio的实时预览功能，配置多尺寸预览参数：

{
  "deviceName": "phone",
  "orientation": "portrait",
  "previewWidth": 360,
  "previewHeight": 180
}

性能优化要点
- 使用@Reusable装饰器复用UI组件
- 网络请求开启HTTP/2复用连接
- 气象图标采用WebP格式压缩
- 内存监控使用HiChecker工具

七、项目部署与发布

签名配置

// build.gradle
signingConfigs {
  release {
    storeFile file('weathercard.jks')
    storePassword '******'
    keyAlias 'release'
    keyPassword '******'
    signAlg 'SHA256withECDSA'
    profile file('release.p7b')
    certpath file('release.cer')
  }
}