AbilityForegroundStateObserver (System API)

The 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';

AbilityForegroundStateObserver

onAbilityStateChanged

onAbilityStateChanged(abilityStateData: AbilityStateData): void

Called when the ability is switched between foreground and background.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API.

Parameters

Name	Type	Mandatory	Description
abilityStateData	AbilityStateData	Yes	Ability state data.

Example

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

let observer: abilityManager.AbilityForegroundStateObserver = {
  onAbilityStateChanged(abilityStateData) {
    console.info(`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}`);
}