跨平台硬件直连:基于Flutter+鸿蒙的轻量化IoT解决方案

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跨平台硬件直连:基于Flutter+鸿蒙的轻量化IoT解决方案

在物联网开发中,跨平台兼容性与硬件直连能力至关重要。本方案结合Flutter的跨平台特性和鸿蒙系统的Sensor API,构建了一套轻量级IoT管控平台。以下是完整的技术实现方案。

Flutter跨平台控制界面实现

Flutter凭借其出色的跨平台性能,成为IoT前端开发的理想选择。以下代码展示了基础控制界面实现,包含温度监控和LED控制功能:

dart 复制代码
import 'package:flutter/material.dart';

void main() => runApp(IoTApp());

class IoTApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'IoT管控平台',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: ControlPanel(),
    );
  }
}

class ControlPanel extends StatefulWidget {
  @override
  _ControlPanelState createState() => _ControlPanelState();
}

class _ControlPanelState extends State<ControlPanel> {
  double temperature = 0.0;
  bool ledStatus = false;
  String connectionStatus = '未连接';

  // 定时更新温度数据
  @override
  void initState() {
    super.initState();
    Timer.periodic(Duration(seconds: 2), (timer) {
      getTemperature();
    });
  }

  void updateTemperature(double newTemp) {
    setState(() {
      temperature = newTemp;
      connectionStatus = '已连接';
    });
  }

  void toggleLed() {
    setState(() => ledStatus = !ledStatus);
    // 调用鸿蒙硬件控制接口
    _sendCommandToDevice(ledStatus ? 'LED_ON' : 'LED_OFF');
  }

  Future<void> _sendCommandToDevice(String command) async {
    // 实现命令发送逻辑
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('IoT管控平台'),
        actions: [
          IconButton(
            icon: Icon(Icons.settings),
            onPressed: () {
              // 打开设置页面
            },
          )
        ],
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text('设备状态: $connectionStatus',
                style: TextStyle(color: Colors.grey)),
            SizedBox(height: 30),
            CircularProgressIndicator(
              value: temperature / 100,
              backgroundColor: Colors.grey[200],
              valueColor: AlwaysStoppedAnimation<Color>(
                temperature > 30 ? Colors.red : Colors.blue,
              ),
            ),
            SizedBox(height: 20),
            Text('当前温度: ${temperature.toStringAsFixed(1)}°C',
                style: TextStyle(fontSize: 24)),
            SizedBox(height: 30),
            ElevatedButton(
              onPressed: toggleLed,
              style: ElevatedButton.styleFrom(
                primary: ledStatus ? Colors.orange : Colors.grey,
                padding: EdgeInsets.symmetric(horizontal: 30, vertical: 15),
              ),
              child: Text(
                ledStatus ? '关闭LED' : '打开LED',
                style: TextStyle(fontSize: 18),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

鸿蒙硬件接入方案

鸿蒙系统提供完善的Sensor API支持,以下Java代码演示了完整的温度传感器接入和管理:

java 复制代码
import ohos.app.Context;
import ohos.sensor.agent.SensorAgent;
import ohos.sensor.bean.CategoryEnvironment;
import ohos.sensor.data.CategoryEnvironmentData;
import ohos.sensor.listener.ICategoryEnvironmentDataCallback;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;

public class SensorManager {
    private static final HiLogLabel LABEL = new HiLogLabel(3, 0xD001100, "SensorManager");
    private final SensorAgent sensorAgent;
    private final ICategoryEnvironmentDataCallback callback;
    private static float currentTemperature = 0f;
    private boolean isSensorActive = false;

    public SensorManager(Context context) {
        sensorAgent = new SensorAgent(context);
        callback = new ICategoryEnvironmentDataCallback() {
            @Override
            public void onSensorDataModified(CategoryEnvironmentData data) {
                currentTemperature = data.getTemperature();
                HiLog.info(LABEL, "温度更新: %{public}f°C", currentTemperature);
                // 数据推送至Flutter界面
                EventBus.getInstance().post(new TemperatureEvent(currentTemperature));
            }
            
            @Override
            public void onAccuracyDataModified(CategoryEnvironmentData data, int accuracy) {
                HiLog.debug(LABEL, "传感器精度变化: %{public}d", accuracy);
            }
        };
    }

    public void startTemperatureSensor() {
        if (!isSensorActive) {
            int result = sensorAgent.startSensorData(
                CategoryEnvironment.SENSOR_TYPE_AMBIENT_TEMPERATURE,
                1000000,  // 1秒采样间隔
                callback
            );
            if (result == 0) {
                isSensorActive = true;
                HiLog.info(LABEL, "温度传感器启动成功");
            } else {
                HiLog.error(LABEL, "温度传感器启动失败, 错误码: %{public}d", result);
            }
        }
    }

    public void stopTemperatureSensor() {
        if (isSensorActive) {
            sensorAgent.stopSensorData(
                CategoryEnvironment.SENSOR_TYPE_AMBIENT_TEMPERATURE,
                callback
            );
            isSensorActive = false;
            HiLog.info(LABEL, "温度传感器已停止");
        }
    }

    public static float getCurrentTemperature() {
        return currentTemperature;
    }

    // LED控制方法
    public void controlLed(boolean isOn) {
        String command = isOn ? "LED_ON" : "LED_OFF";
        HiLog.info(LABEL, "执行LED控制命令: %{public}s", command);
        // 实际硬件控制逻辑
    }
}

跨平台通信方案

提供两种可靠的通信实现方式,满足不同场景需求:

1. 平台通道方案

Flutter端完整实现:

dart 复制代码
import 'package:flutter/services.dart';

const platform = MethodChannel('samples.flutter.dev/sensor');
const eventChannel = EventChannel('samples.flutter.dev/sensor_updates');

class SensorService {
  static Future<double> getTemperature() async {
    try {
      final result = await platform.invokeMethod('getTemperature');
      return double.parse(result.toString());
    } on PlatformException catch (e) {
      print("温度获取失败: '${e.message}'.");
      throw Exception('温度获取失败');
    }
  }

  static Stream<double> get temperatureUpdates {
    return eventChannel
        .receiveBroadcastStream()
        .map((event) => double.parse(event.toString()))
        .handleError((error) {
      print('温度数据流错误: $error');
    });
  }

  static Future<void> controlLed(bool isOn) async {
    try {
      await platform.invokeMethod('controlLed', {'status': isOn});
    } on PlatformException catch (e) {
      print("LED控制失败: '${e.message}'.");
      throw Exception('LED控制失败');
    }
  }
}

鸿蒙端完整实现:

java 复制代码
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.app.Context;
import ohos.eventhandler.EventHandler;
import ohos.eventhandler.EventRunner;
import ohos.eventhandler.InnerEvent;
import io.flutter.embedding.android.FlutterAbilitySlice;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.plugin.common.EventChannel;
import io.flutter.plugin.common.MethodChannel;

public class MainAbilitySlice extends FlutterAbilitySlice {
    private static final String CHANNEL = "samples.flutter.dev/sensor";
    private static final String EVENT_CHANNEL = "samples.flutter.dev/sensor_updates";
    private SensorManager sensorManager;
    private EventChannel.EventSink eventSink;
    private final EventHandler handler = new EventHandler(EventRunner.getMainEventRunner()) {
        @Override
        protected void processEvent(InnerEvent event) {
            if (eventSink != null) {
                eventSink.success(SensorManager.getCurrentTemperature());
            }
        }
    };

    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        sensorManager = new SensorManager(this);
        
        // 方法通道
        new MethodChannel(getFlutterEngine().getDartExecutor(), CHANNEL)
            .setMethodCallHandler((call, result) -> {
                switch (call.method) {
                    case "getTemperature":
                        result.success(SensorManager.getCurrentTemperature());
                        break;
                    case "controlLed":
                        boolean status = call.argument("status");
                        sensorManager.controlLed(status);
                        result.success(null);
                        break;
                    default:
                        result.notImplemented();
                }
            });
            
        // 事件通道
        new EventChannel(getFlutterEngine().getDartExecutor(), EVENT_CHANNEL)
            .setStreamHandler(new EventChannel.StreamHandler() {
                @Override
                public void onListen(Object args, EventChannel.EventSink sink) {
                    eventSink = sink;
                    sensorManager.startTemperatureSensor();
                    handler.sendEvent(InnerEvent.get(0, 0, null), 1000);
                }

                @Override
                public void onCancel(Object args) {
                    eventSink = null;
                    sensorManager.stopTemperatureSensor();
                }
            });
    }
}

2. RESTful API方案

适用于远程控制场景,鸿蒙设备作为服务端提供数据接口:

鸿蒙端REST服务实现:

java 复制代码
import ohos.app.Context;
import ohos.net.http.HttpRequest;
import ohos.net.http.HttpResponse;
import ohos.net.http.HttpURLConnection;
import ohos.app.Context;
import ohos.app.AbilityContext;
import ohos.app.ServiceAbility;
import ohos.rpc.IRemoteObject;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class RestService extends ServiceAbility {
    private static final HiLogLabel LABEL = new HiLogLabel(3, 0xD001100, "RestService");
    private static final int PORT = 8080;
    private HttpServer httpServer;
    private SensorManager sensorManager;

    @Override
    public void onStart(AbilityContext abilityContext) {
        super.onStart(abilityContext);
        HiLog.info(LABEL, "REST服务启动");
        sensorManager = new SensorManager(abilityContext);
        startHttpServer();
    }

    private void startHttpServer() {
        try {
            httpServer = new HttpServer(PORT);
            httpServer.addHandler("/api/temperature", (request, response) -> {
                response.setContentType("application/json");
                Map<String, Object> data = new HashMap<>();
                data.put("temperature", SensorManager.getCurrentTemperature());
                data.put("timestamp", System.currentTimeMillis());
                response.send(200, new Gson().toJson(data));
            });
            
            httpServer.addHandler("/api/led", (request, response) -> {
                String method = request.getMethod();
                if ("POST".equals(method)) {
                    Map<String, String> params = request.getParams();
                    boolean status = Boolean.parseBoolean(params.get("status"));
                    sensorManager.controlLed(status);
                    response.send(200, "{\"status\":\"success\"}");
                } else {
                    response.send(405, "{\"error\":\"Method not allowed\"}");
                }
            });
            
            httpServer.start();
            HiLog.info(LABEL, "HTTP服务器已启动,监听端口: %{public}d", PORT);
        } catch (IOException e) {
            HiLog.error(LABEL, "HTTP服务器启动失败: %{public}s", e.getMessage());
        }
    }

    @Override
    public void onStop() {
        super.onStop();
        if (httpServer != null) {
            httpServer.stop();
            HiLog.info(LABEL, "HTTP服务器已停止");
        }
    }
}

Flutter端HTTP客户端实现:

dart 复制代码
import 'package:http/http.dart' as http;
import 'dart:convert';

class HttpSensorService {
  static const String baseUrl = 'http://192.168.1.100:8080';
  
  static Future<double> getTemperature() async {
    try {
      final response = await http.get(Uri.parse('$baseUrl/api/temperature'));
      if (response.statusCode == 200) {
        final data = json.decode(response.body);
        return data['temperature'].toDouble();
      }
      throw Exception('Failed to get temperature');
    } catch (e) {
      throw Exception('HTTP请求失败: $e');
    }
  }
  
  static Future<void> controlLed(bool isOn) async {
    try {
      final response = await http.post(
        Uri.parse('$baseUrl/api/led'),
        body: {'status': isOn.toString()}
      );
      if (response.statusCode != 200) {
        throw Exception('LED控制失败');
      }
    } catch (e) {
      throw Exception('HTTP请求失败: $e');
    }
  }
}

系统架构设计

完整的系统采用三层架构方案:

  1. 硬件层

    • 鸿蒙设备作为硬件接入节点
    • 支持多种传感器接入(温度、湿度、光照等)
    • 提供执行器控制接口(LED、继电器等)
    • 实现设备管理(连接状态、固件版本等)
  2. 通信层

    • 本地通信:平台通道(MethodChannel/EventChannel)
    • 远程通信:RESTful API(HTTP/HTTPS)
    • 数据协议:JSON格式统一数据交换
    • 安全机制:TLS加密、访问令牌
  3. 应用层

    • Flutter跨平台UI(Android/iOS/Web)
    • 设备管理界面(添加/删除/配置设备)
    • 实时数据监控(图表展示、历史记录)
    • 控制面板(场景模式、定时任务)
    • 告警系统(阈值设置、推送通知)

部署流程

完整的部署实施流程:

  1. 鸿蒙应用开发与传感器集成

    • 配置鸿蒙开发环境(DevEco Studio)
    • 实现传感器数据采集模块
    • 开发硬件控制接口
    • 集成通信服务(平台通道/REST API)
  2. Flutter界面开发与通信模块实现

    • 搭建Flutter开发环境
    • 设计响应式UI布局
    • 实现与鸿蒙设备的通信模块
    • 开发数据可视化组件
  3. 硬件连接测试与性能优化

    • 功能测试(传感器数据准确性、控制响应)
    • 压力测试(多设备连接、大数据量传输)
    • 功耗优化(传感器采样频率调整)
    • 稳定性测试(长时间运行)
  4. 多平台应用打包发布

    • 鸿蒙应用打包(HAP包)
    • Flutter应用打包(Android APK/iOS IPA/Web)
    • 部署文档编写
    • 应用商店发布

方案优势

本方案融合了Flutter的跨平台优势与鸿蒙的硬件接入能力,具有以下特点:

  1. 开发效率高

    • 一套代码多平台运行(Android/iOS/Web)
    • 热重载快速迭代开发
    • 丰富的Flutter插件生态系统
  2. 维护成本低

    • 统一代码库,减少维护工作量
    • 模块化设计,易于功能扩展
    • 自动化测试框架支持
  3. 性能优异

    • Flutter高性能渲染引擎
    • 鸿蒙轻量化系统资源占用低
    • 优化的通信协议减少延迟
  4. 应用场景广泛

    • 智能家居(温控系统、智能照明)
    • 工业监测(设备状态监控)
    • 环境监测(气象站、水质检测)
    • 农业物联网(温室控制、精准灌溉)
  5. 扩展性强

    • 支持多种通信协议(BLE/WiFi/LoRa)
    • 可接入第三方云平台
    • 支持边缘计算功能扩展
      欢迎大家加入开源鸿蒙跨平台开发者社区,一起共建开源鸿蒙跨平台生态。
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