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管理应用与Wear Engine服务的连接状态

监测应用与Wear Engine服务的连接状态​

华为运动健康App在后台停止服务（如功耗过高），从而导致应用与Wear Engine服务的连接状态发生变化。对于类似这种不确定的断开情况，开发者可以通过本功能特性了解当前应用和Wear Engine的连接状态。前提是在服务断开前，开发者已经使用该功能订阅过对Wear Engine服务连接状态的监测。

  1. 在使用Wear Engine服务前，请导入WearEngine与相关模块。

    import { wearEngine } from '@kit.WearEngine';
    import { BusinessError } from '@kit.BasicServicesKit';

  2. 构造当服务连接断开时执行的回调函数。

    let callback = () => {
      console.info(`The service destruction event`);
    }

  3. 调用wearEngine中的on方法，订阅监听应用与Wear Engine服务的断联事件。

    try {
      wearEngine.on('serviceDie', callback);
      console.info(`Succeeded in subscribing the service destruction event.`);
    } catch (error) {
      const err: BusinessError = error as BusinessError;
      console.error(`Failed to subscribe the service destruction event. Code is ${err.code}, message is ${err.message}`);
    }

  4. 调用wearEngine中的off方法，取消监听应用与Wear Engine服务的断联事件。需要传入订阅监听时的同一个回调函数对象。

    try {
      wearEngine.off('serviceDie', callback);
      console.info(`Succeeded in unsubscribing the service destruction event.`);
    } catch (error) {
      const err: BusinessError = error as BusinessError;
      console.error(`Failed to unsubscribe the service destruction event. Code is ${err.code}, message is ${err.message}`);
    }

断开应用与Wear Engine服务的连接​

断开后，将释放Wear Engine资源，监测设备状态、收消息、收文件等功能不可用，监听服务端断联事件的回调函数不会执行，同时会清理掉之前注册的回调函数。如需重新连接，主动调用任意接口即可。

  1. 在使用Wear Engine服务前，请导入WearEngine与相关模块。

    import { wearEngine } from '@kit.WearEngine';
    import { BusinessError } from '@kit.BasicServicesKit';

  2. 调用wearEngine中的destroy方法，断开应用与Wear Engine服务的连接。

    wearEngine.destroy().then(() => {
      console.info(`Succeeded in destroying wear engine channel`);
    }).catch((error: BusinessError) => {
      console.error(`Failed to destroy wear engine channel. Code is ${error.code}, message is ${error.message}`);
    })