harmony 鸿蒙AbilityForegroundStateObserver (System API)

2025-06-12
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AbilityForegroundStateObserver (System API)

The AbilityForegroundStateObserver module defines the listener used to listen for ability foreground and background state changes.

NOTE

The initial APIs of this module are supported since API version 11. Newly added APIs will be marked with a superscript to indicate their earliest API version. The APIs provided by this module are system APIs.

Modules to Import

import { abilityManager } from '@kit.AbilityKit';

Attributes

System capability: SystemCapability.Ability.AbilityRuntime.Core

Name	Type	Readable	Writable	Description
onAbilityStateChanged	AsyncCallback<void>	Yes	No	Callback invoked when the foreground or background state of an ability changes. The parameter type passed in is AbilityStateData.

Example

import { abilityManager } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

let observer: abilityManager.AbilityForegroundStateObserver = {
  onAbilityStateChanged(abilityStateData) {
    console.log(`onAbilityStateChanged: ${JSON.stringify(abilityStateData)}`);
  },
};
try {
  abilityManager.on('abilityForegroundState', observer);
} catch (paramError) {
  let code = (paramError as BusinessError).code;
  let message = (paramError as BusinessError).message;
  console.error(`error code: ${code}, error msg: ${message}`);
}