如何通过Service Ability实现设备状态的长时监控与断网自动重连？

import ServiceExtensionAbility from '@ohos.app.ability.ServiceExtensionAbility';

export default class MyServiceAbility extends ServiceExtensionAbility {
  onConnect(want: Want): void {
    console.log('ServiceAbility onConnect');
    // 初始化监控任务
    this.startMonitoring();
  }

  onDisconnect(want: Want): void {
    console.log('ServiceAbility onDisconnect');
    this.stopMonitoring();
  }

  // 启动设备监控逻辑
  private startMonitoring(): void {
    this.setupNetworkListener();
  }

  // 停止监控并释放资源
  private stopMonitoring(): void {
    this.removeNetworkListener();
  }
}
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{
  "module": {
    "abilities": [
      {
        "name": "MyServiceAbility",
        "type": "service",
        "backgroundModes": ["dataTransfer", "location"], // 后台模式
        "visible": true
      }
    ],
    "requestPermissions": [
      {
        "name": "ohos.permission.GET_NETWORK_INFO",
        "reason": "Monitor network status"
      },
      {
        "name": "ohos.permission.KEEP_BACKGROUND_RUNNING",
        "reason": "Keep service alive in background"
      }
    ]
  }
}
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import connection from '@ohos.net.connection';

class NetworkMonitor {
  private listenerId: number | null = null;

  // 注册网络状态监听
  registerNetworkListener(callback: (state: connection.NetState) => void): void {
    this.listenerId = connection.on('netAvailable', (data: { netHandle: connection.NetHandle }) => {
      const netState = connection.getDefaultNetSync();
      callback(netState);
    });
  }

  // 移除监听
  unregisterNetworkListener(): void {
    if (this.listenerId !== null) {
      connection.off('netAvailable', this.listenerId);
      this.listenerId = null;
    }
  }
}
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private networkMonitor: NetworkMonitor | null = null;

private setupNetworkListener(): void {
  this.networkMonitor = new NetworkMonitor();
  this.networkMonitor.registerNetworkListener((netState: connection.NetState) => {
    if (!netState.isAvailable) {
      this.handleNetworkDisconnected();
    } else {
      this.handleNetworkReconnected();
    }
  });
}
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private retryCount: number = 0;
private readonly MAX_RETRY: number = 5;

private async reconnect(): Promise<void> {
  while (this.retryCount < this.MAX_RETRY) {
    try {
      const success = await this.attemptReconnect();
      if (success) {
        this.retryCount = 0;
        return;
      }
    } catch (error) {
      console.error(`Reconnect attempt ${this.retryCount} failed: ${error}`);
    }

    // 指数退避延迟
    const delay = Math.pow(2, this.retryCount) * 1000;
    await new Promise(resolve => setTimeout(resolve, delay));
    this.retryCount++;
  }
}

private async attemptReconnect(): Promise<boolean> {
  const netState = connection.getDefaultNetSync();
  if (!netState.isAvailable) {
    return false;
  }
  // 具体重连逻辑（如重连服务器）
  return true;
}
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import taskpool from '@ohos.taskpool';

private handleNetworkDisconnected(): void {
  taskpool.execute(async () => {
    await this.reconnect();
  }).catch((err) => {
    console.error(`Reconnect task failed: ${err}`);
  });
}
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import backgroundTaskManager from '@ohos.resourceschedule.backgroundTaskManager';

// 在 Service 启动时申请保活
private requestBackgroundMode(): void {
  backgroundTaskManager.requestSuspendDelay('NetworkMonitor', (err, delayId) => {
    if (err) {
      console.error(`Request background delay failed: ${err}`);
      return;
    }
    console.log(`Background delay granted, ID: ${delayId}`);
  });
}
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private removeNetworkListener(): void {
  if (this.networkMonitor) {
    this.networkMonitor.unregisterNetworkListener();
    this.networkMonitor = null;
  }
}
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import hilog from '@ohos.hilog';

hilog.info(0x0000, 'NETWORK_TAG', 'Network state changed: %{public}s', state);
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import featureAbility from '@ohos.ability.featureAbility';

let want = {
  bundleName: 'com.example.myapp',
  abilityName: 'MyServiceAbility'
};
featureAbility.startAbility(want).then(() => {
  console.log('Service started');
}).catch((err) => {
  console.error(`Start service failed: ${err}`);
});
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