harmony 鸿蒙@ohos.app.ability.CompletionHandler (CompletionHandler)

2025-06-12
浏览 (4)

@ohos.app.ability.CompletionHandler (CompletionHandler)

CompletionHandler is an optional parameter of StartOptions and is used to handle the results of application launching requests.

NOTE

The initial APIs of this module are supported since API version 20. 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.

Constraints

Currently, this module can be used in the following APIs: - startAbility - startAbilityForResult

Modules to Import

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

CompletionHandler

CompletionHandler provides two callback functions, onRequestSuccess and onRequestFailure, to handle the results of successful and failed application launching requests, respectively.

onRequestSuccess

onRequestSuccess(elementName: ElementName, message: string): void

Callback invoked when the application is successfully launched.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Name	Type	Mandatory	Description
elementName	ElementName	Yes	Element name of the launched application.
message	string	Yes	Message displayed when the application is successfully launched. This message is in JSON format, as follows: { “errMsg”: “Succeeded.” }

Example

See Usage of CompletionHandler.

onRequestFailure

onRequestFailure(elementName: ElementName, message: string): void

Callback invoked when the application fails to be launched.

System capability: SystemCapability.Ability.AbilityRuntime.Core

Parameters

Name	Type	Mandatory	Description
elementName	ElementName	Yes	Element name of the application that fails to be launched.
message	string	Yes	Message displayed when the application fails to be launched. This message is in JSON format, as follows: { “errMsg”: “xxx” } The value of xxx is described as follows: Failed to call <api-name>: An error occurs when calling the API. <api-name> is the specific API name, for example, startAbility. User refused redirection: The user has closed the application redirection dialog box. User closed the implicit startup picker: The user has closed the dialog box for selecting an application for implicit startup. User closed the app clone picker: The user has closed the dialog box for selecting a cloned application. Free installation failed: The free installation fails.

Example

See Usage of CompletionHandler.

Usage of CompletionHandler

  import { UIAbility, Want, StartOptions, CompletionHandler, bundleManager } from '@kit.AbilityKit';
  import { BusinessError } from '@kit.BasicServicesKit';

  export default class EntryAbility extends UIAbility {
    onForeground() {
      let want: Want = {
        deviceId: '',
        bundleName: 'com.example.myapplication',
        abilityName: 'EntryAbility'
      };

      let completionHandler: CompletionHandler = {
        onRequestSuccess: (elementName: bundleManager.ElementName, message: string): void => {
          console.log(`${elementName.bundleName}-${elementName.moduleName}-${elementName.abilityName} start succeeded: ${message}`);
        },
        onRequestFailure: (elementName: bundleManager.ElementName, message: string): void => {
          console.log(`${elementName.bundleName}-${elementName.moduleName}-${elementName.abilityName} start failed: ${message}`);
        }
      };

      let options: StartOptions = {
        completionHandler: completionHandler
      };

      try {
        this.context.startAbility(want, options, (err: BusinessError) => {
          if (err.code) {
            // Process service logic errors.
            console.error(`startAbility failed, code is ${err.code}, message is ${err.message}`);
            return;
          }
          // Carry out normal service processing.
          console.info('startAbility succeed');
        });
      } catch (err) {
        // Process input parameter errors.
        let code = (err as BusinessError).code;
        let message = (err as BusinessError).message;
        console.error(`startAbility failed, code is ${code}, message is ${message}`);
      }
    }
  }