1.notificationManager.cancelAll
支持设备Phone2in1TabletCarWearable
cancelAll(callback: AsyncCallback<void>): void
取消当前应用所有已发布的通知。使用callback异步回调。
系统能力：SystemCapability.Notification.Notification
 

示例：

import { BusinessError } from '@kit.BasicServicesKit';// cancel回调
let cancelAllCallback = (err: BusinessError): void => {if (err) {console.error(`Failed to cancel all notification. Code is ${err.code}, message is ${err.message}`);} else {console.info(`Succeeded in canceling all notification.`);}
}
notificationManager.cancelAll(cancelAllCallback);

2.notificationManager.cancelAll
支持设备Phone2in1TabletCarWearable
cancelAll(): Promise<void>
取消当前应用所有已发布的通知。使用Promise异步回调。
系统能力：SystemCapability.Notification.Notification
 

示例：

import { BusinessError } from '@kit.BasicServicesKit';notificationManager.cancelAll().then(() => {console.info(`Succeeded in canceling all notification.`);
}).catch((err: BusinessError) => {console.error(`Failed to cancel all notification. Code is ${err.code}, message is ${err.message}`);

本文主要参考引用自HarmonyOS官方网站