@@ -9,7 +9,7 @@ For an OpenHarmony application, each process has a main thread to provide the fo
- Process application code callbacks (event processing and lifecycle management).
- Receive messages sent by the worker thread.
In addition to the main thread, there is an independent thread, named worker. The worker thread is mainly used to perform time-consuming operations. The worker thread is created in the main thread and is independent from the main thread. It cannot directly operate the UI. A maximum of seven worker threads can be created.
In addition to the main thread, there is an independent thread, named worker. The worker thread is mainly used to perform time-consuming operations. The worker thread is created in the main thread and is independent from the main thread. It cannot directly operate the UI. A maximum of eight worker threads can be created.
Based on the OpenHarmony thread model, different services run on different threads. Service interaction requires inter-thread communication. In the same process, threads can communicate with each other in Emitter or Worker mode. Emitter is mainly used for event synchronization between threads, and Worker is mainly used to execute time-consuming tasks.
Based on the OpenHarmony application model, you can use any of the following ways to implement data synchronization between UIAbility components and UI pages:
-[Using EventHub for Data Synchronization](#using-eventhub-for-data-synchronization): The **EventHub** object is provided by the base class **Context**. It allows events to be transferred using the publish/subscribe (pub/sub) pattern. Specifically, after subscribing to an event, your application will receive the event and process it accordingly when the event is published.
-[Using globalThis for Data Synchronization](#using-globalthis-for-data-synchronization): **globalThis** is a global object inside the ArkTS engine instance and can be accessed by components such as UIAbility, ExtensionAbility, and UI page.
-[Using globalThis for Data Synchronization](#using-globalthis-for-data-synchronization): **globalThis** is a global object inside the ArkTS engine instance and can be accessed by the UIAbility components, ExtensionAbility components, and ArkUI pages inside the instance.
-[Using AppStorage or LocalStorage for Data Synchronization](#using-appstorage-or-localstorage-for-data-synchronization): ArkUI provides two application-level state management solutions: AppStorage and LocalStorage, which implement application- and UIAbility-level data synchronization, respectively.
## Using EventHub for Data Synchronization
[EventHub](../reference/apis/js-apis-inner-application-eventHub.md) provides an event mechanism for the UIAbility or ExtensionAbility component so that they can subscribe to, unsubscribe from, and trigger events.
[EventHub](../reference/apis/js-apis-inner-application-eventHub.md) provides an event mechanism for the UIAbility component so that they can subscribe to, unsubscribe from, and trigger events.
Before using the APIs provided by **EventHub**, you must obtain an **EventHub** object, which is provided by the [base class Context](application-context-stage.md).
Before using the APIs provided by **EventHub**, you must obtain an **EventHub** object, which is provided by the [base class Context](application-context-stage.md).
1. Call [eventHub.on()](../reference/apis/js-apis-inner-application-eventHub.md#eventhubon) in the UIAbility in either of the following ways to register a custom event **event1**.
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@@ -90,6 +90,7 @@ Before using the APIs provided by **EventHub**, you must obtain an **EventHub**
**globalThis** is a global object inside the [ArkTS engine instance](thread-model-stage.md) and can be used by UIAbility, ExtensionAbility, and UI page inside the engine. Therefore, you can use **globalThis** for data synchronization.
**Figure 1** Using globalThis for data synchronization
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@@ -123,14 +124,14 @@ To implement data synchronization between the UIAbility component and UI page, y
```ts
letentryAbilityWant;
@Entry
@Component
structIndex{
aboutToAppear(){
entryAbilityWant=globalThis.entryAbilityWant;
}
// UI page display.
build(){
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@@ -160,7 +161,7 @@ To implement data synchronization between two UIAbility components in the same a
```ts
importUIAbilityfrom'@ohos.app.ability.UIAbility'
exportdefaultclassUIAbilityBextendsUIAbility{
onCreate(want,launch){
// UIAbilityB reads name from globalThis and outputs it.
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@@ -193,7 +194,7 @@ To implement data synchronization between the UIAbility and ExtensionAbility com
@@ -206,11 +207,14 @@ To implement data synchronization between the UIAbility and ExtensionAbility com
### Precautions for Using globalThis
**Figure 2** Precautions for using globalThis
**Figure 2** Precautions for using globalThis
- In the stage model, all the UIAbility components in a process share one ArkTS engine instance. When using **globalThis**, do not store objects with the same name. For example, if UIAbilityA and UIAbilityB use **globalThis** to store two objects with the same name, the object stored earlier will be overwritten.
-**globalThis** cannot be used across processes. The UIAbility and ExtensionAbility components of different processes cannot use **globalThis** to share data. For details about the process model and inter-process communication, see [Process Model Overview](./process-model-stage.md#process-model-overview).
- This problem does not occur in the FA model because each UIAbility component uses an independent engine.
- The lifecycle of an object bound to **globalThis** is the same as that of the ArkTS engine instance. To minimize memory usage, you are advised to assign the value **null** to the object when it is not in use.
| userId | number | No | User ID. The default value is the user ID of the caller. The value must be greater than or equal to 0. You can call [queryOsAccountLocalIdFromProcess](js-apis-osAccount.md#getOsAccountLocalId) to obtain the user ID of the current process.|
| installFlag | number | No | Installation flag. The value **0** means initial installation and **1** means overwrite installation. The default value is **0**.|
| installFlag | number | No | Installation flag. The value **0x00** means initial installation, **0x01** means overwrite installation, and **0x10** means installation-free. The default value is **0x00**.|
| isKeepData | boolean | No | Whether to retain the data directory during bundle uninstall. The default value is **false**.|
| hashParams | Array<[HashParam](#hashparam)> | No| Hash parameters. By default, no value is passed. |
| crowdtestDeadline| number | No | End date of crowdtesting. The default value is **-1**, indicating that no end date is specified for crowdtesting.|
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@@ -779,7 +779,7 @@ Defines the parameters that need to be specified for bundle installation, uninst
## UninstallParam<sup>10+</sup>
Defines the parameters required for the uninstallation of a shared bundle.
Defines the parameters required for the uninstall of a shared bundle.
