harmony 鸿蒙Unsubscribing from Common Events in Dynamic Mode

2023-02-03
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Unsubscribing from Common Events in Dynamic Mode

When to Use

You can call unsubscribe() to unsubscribe from a common event that is no longer required in dynamic mode.

Available APIs

API	Description
unsubscribe(subscriber: CommonEventSubscriber, callback?: AsyncCallback)	Unsubscribes from a common event.

How to Develop

Import the commonEventManager module.

   import commonEventManager from '@ohos.commonEventManager';
   import Base from '@ohos.base';

Subscribe to an event by following the procedure described in Subscribing to Common Events in Dynamic Mode.
Call unsubscribe in CommonEvent to unsubscribe from the common event.

   // The subscriber object is created during event subscription.
   if (subscriber !== null) {
       commonEventManager.unsubscribe(subscriber, (err: Base.BusinessError) => {
           if (err) {
               console.error(`[CommonEvent] UnsubscribeCallBack err=${JSON.stringify(err)}`);
           } else {
               console.info(`[CommonEvent] Unsubscribe`);
               subscriber = null;
           }
       })
   }