js-apis-application-applicationContext.md 4.5 KB

ApplicationContext

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version. The APIs of this module can be used only in the stage model.

Provides application-level context and APIs for registering and deregistering the ability lifecycle listener in an application.

Modules to Import

import Ability from '@ohos.application.Ability';

How to Use

Before calling any APIs in ApplicationContext, obtain an ApplicationContext instance through the context instance.

let applicationContext = this.context.getApplicationContext();

ApplicationContext.registerAbilityLifecycleCallback

registerAbilityLifecycleCallback(callback: AbilityLifecycleCallback): number;

Registers a listener to monitor the ability lifecycle of the application.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Name Type Mandatory Description
AbilityLifecycleCallback callback Yes Callback used to return the ID of the registered listener.

Return value

Type Description
number ID of the registered listener. The ID is incremented by 1 each time the listener is registered. When the ID exceeds 2^63-1, -1 is returned.

ApplicationContext.unregisterAbilityLifecycleCallback

unregisterAbilityLifecycleCallback(callbackId: number, callback: AsyncCallback<void>): void;

Deregisters the listener that monitors the ability lifecycle of the application.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Name Type Mandatory Description
callbackId number Yes ID of the listener to deregister.
AsyncCallback callback Yes Callback used to return the result.

Example

import AbilityStage from "@ohos.application.AbilityStage";

var lifecycleid;

export default class MyAbilityStage extends AbilityStage {
    onCreate() {
        console.log("MyAbilityStage onCreate")
        let AbilityLifecycleCallback  =  {
            onAbilityCreate(ability){
                console.log("AbilityLifecycleCallback onAbilityCreate ability:" + JSON.stringify(ability));        
            },
            onAbilityWindowStageCreate(ability){
                console.log("AbilityLifecycleCallback onAbilityWindowStageCreate ability:" + JSON.stringify(ability));           
            },
            onAbilityWindowStageDestroy(ability){
                console.log("AbilityLifecycleCallback onAbilityWindowStageDestroy ability:" + JSON.stringify(ability));
            },
            onAbilityDestroy(ability){
                console.log("AbilityLifecycleCallback onAbilityDestroy ability:" + JSON.stringify(ability));             
            },
            onAbilityForeground(ability){
                console.log("AbilityLifecycleCallback onAbilityForeground ability:" + JSON.stringify(ability));             
            },
            onAbilityBackground(ability){
                console.log("AbilityLifecycleCallback onAbilityBackground ability:" + JSON.stringify(ability));              
            },
            onAbilityContinue(ability){
                console.log("AbilityLifecycleCallback onAbilityContinue ability:" + JSON.stringify(ability));
            }
        }
        // 1. Obtain applicationContext through the context attribute.
        let applicationContext = this.context.getApplicationContext();
        // 2. Use applicationContext to register a listener for the ability lifecycle in the application.
        lifecycleid = applicationContext.registerAbilityLifecycleCallback(AbilityLifecycleCallback);
        console.log("registerAbilityLifecycleCallback number: " + JSON.stringify(lifecycleid));       
    }
    onDestroy() {
        let applicationContext = this.context.getApplicationContext();
        applicationContext.unregisterAbilityLifecycleCallback(lifecycleid, (error, data) => {
        console.log("unregisterAbilityLifecycleCallback success, err: " + JSON.stringify(error));
        });
    }
}