harmony 鸿蒙Publishing a Live View Notification (for System Applications Only)

2025-06-12
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Publishing a Live View Notification (for System Applications Only)

The live view notification provides real-time progress of long-duration tasks, including voice recording, screen recording, audio and video playback, timing, and phone call. Such type of notification is not stored persistently, and its lifecycle is consistent with that of the notification publisher.

Table 1 Types of live view notifications

Type	Value	Description
NOTIFICATION_CONTENT_SYSTEM_LIVE_VIEW¹¹⁺	5	Live view notification.

Available APIs

The following table describes the APIs for notification publishing. You can specify the notification information – content, ID, slot type, and delivery time – by setting the NotificationRequest parameter in the APIs.

API	Description
publish(request: NotificationRequest, callback: AsyncCallback<void>): void	Publishes a notification.
cancel(id: number, label: string, callback: AsyncCallback<void>): void	Cancels a specified notification.

How to Develop

Import the modules.

   import { notificationManager } from '@kit.NotificationKit';
   import { BusinessError } from '@kit.BasicServicesKit';
   import { image } from '@kit.ImageKit';
   import { hilog } from '@kit.PerformanceAnalysisKit';

   const TAG: string = '[PublishOperation]';
   const DOMAIN_NUMBER: number = 0xFF00;

Publishes a notification.

In addition to the parameters in the normal text notification, the system live view notification provides the typeCode, capsule, button, time, and progress parameters. For details, see NotificationSystemLiveViewContent.

  ```ts
  let imagePixelMap: image.PixelMap|undefined = undefined; // Obtain the image pixel map information.
  let color = new ArrayBuffer(4);
  imagePixelMap = await image.createPixelMap(color, {
    size: {
      height: 1,
      width: 1
    }
  })
  if(imagePixelMap !== undefined) {
    let notificationRequest: notificationManager.NotificationRequest = {
      notificationSlotType: notificationManager.SlotType.LIVE_VIEW, // Live view
      id: 0, // Notification ID. The default value is 0.
      content: {
        notificationContentType : notificationManager.ContentType.NOTIFICATION_CONTENT_SYSTEM_LIVE_VIEW,
        systemLiveView: {
          title: "test_title",
          text:"test_text",
          typeCode: 1, // Type of the invoking service.
          // Button
          button: {
            names: ["buttonName1"],
            icons: [imagePixelMap],
          },
          // Capsule
          capsule: {
            title: "testTitle",
            icon: imagePixelMap,
            backgroundColor: "testColor",
          },
          // Progress. To update the progress, you only need to modify the progress value and publish the notification again.
          progress: {
            maxValue: 100,
            currentValue: 21,
            isPercentage: false,
          },
          // Time
          time: {
            initialTime: 12,
            isCountDown: true,
            isPaused: true,
            isInTitle: false,
          }
        }
      }
    };
    // publish callback
    let publishCallback = (err: BusinessError): void => {
      if (err) {
        hilog.error(DOMAIN_NUMBER, TAG, `publish failed, code is ${err.code}, message is ${err.message}`);
      } else {
        hilog.info(DOMAIN_NUMBER, TAG, `publish success`);
      }
    };
    // Button callback (It is returned when the button is touched. You can determine how to process the callback.)
    let onResponseCallback = (id:number, option:notificationManager.ButtonOptions) => {
      hilog.info(DOMAIN_NUMBER, TAG, `response callback: ` + JSON.stringify(option) + `notificationId` + id);
    }
    let systemLiveViewSubscriber: notificationManager.SystemLiveViewSubscriber  = {
      onResponse: onResponseCallback
    };
    // Subscribe to the system live view notification (button).
    await notificationManager.subscribeSystemLiveView(systemLiveViewSubscriber);
    // Publish the notification.
    notificationManager.publish(notificationRequest, publishCallback);
  }
  ```