harmony 鸿蒙AppForegroundStateObserver (System API)

2025-06-12
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AppForegroundStateObserver (System API)

The AppForegroundStateObserver module defines the listener used to listen for application startup and exit state changes. It can be used as an input parameter of on to listen for the state changes of all applications.

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 { appManager } from '@kit.AbilityKit';

Attributes

System API: This is a system API.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Name	Type	Readable	Writable	Description
onAppStateChanged	AsyncCallback<void>	Yes	No	Callback invoked when the startup or exit state of an application changes. The parameter type passed in is AppStateData.

Example

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

let observer: appManager.AppForegroundStateObserver = {
  onAppStateChanged(appStateData) {
    console.log(`onAppStateChanged appStateData: ${JSON.stringify(appStateData)}`);
  },
};
appManager.on('appForegroundState', observer);