Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
The **\<List>** component is a scrollable container. By default, it taks up the entire screen height. When any component with a fixed height takes up part of the screen height, you need to explicitly specify **layoutWeight(1)** for the parent container of the **\<List>** component to take up the remaining height instead of the entire screen height.
The **\<List>** component is a scrollable container. By default, it takes up the entire screen height. When any component with a fixed height takes up part of the screen height, you need to explicitly specify **layoutWeight(1)** for the parent container of the **\<List>** component to take up the remaining height instead of the entire screen height.
## How do I center child components in a grid container?
@@ -13,14 +13,14 @@ Each application can subscribe to common events as required. After your applicat
## Common Event Subscription Development
### When to Use
You can create a subscriber object to subscribe to a common event to obtain the parameters passed in the event. Certain system common events require specific permissions to subscribe to. For details, see [Required Permissions](../reference/apis/js-apis-commonEvent.md).
You can create a subscriber object to subscribe to a common event to obtain the parameters passed in the event. Certain system common events require specific permissions to subscribe to. For details, see [Required Permissions](../reference/apis/js-apis-commonEvent.md#required-permissions).
| commonEvent.createSubscriber(subscribeInfo: CommonEventSubscribeInfo, callback: AsyncCallback) | Creates a subscriber. This API uses a callback to return the result.|
| commonEvent.createSubscriber(subscribeInfo: CommonEventSubscribeInfo) | Creates a subscriber. This API uses a promise to return the result. |
| commonEvent.subscribe(subscriber: CommonEventSubscriber, callback: AsyncCallback) | Subscribes to common events.|
| createSubscriber(subscribeInfo: CommonEventSubscribeInfo, callback: AsyncCallback) | Creates a subscriber. This API uses a callback to return the result.|
| createSubscriber(subscribeInfo: CommonEventSubscribeInfo) | Creates a subscriber. This API uses a promise to return the result. |
| subscribe(subscriber: CommonEventSubscriber, callback: AsyncCallback) | Subscribes to common events.|
### How to Develop
1. Import the **commonEvent** module.
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@@ -82,8 +82,8 @@ You can use the **publish** APIs to publish a custom common event, which can car
### Available APIs
| API | Description|
| ---------------------------------- | ------ |
| commonEvent.publish(event: string, callback: AsyncCallback) | Publishes a common event.|
| commonEvent.publish(event: string, options: CommonEventPublishData, callback: AsyncCallback) | Publishes a common event with given attributes.|
| publish(event: string, callback: AsyncCallback) | Publishes a common event.|
| publish(event: string, options: CommonEventPublishData, callback: AsyncCallback) | Publishes a common event with given attributes.|
### How to Develop
#### Development for Publishing a Common Event
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@@ -119,7 +119,7 @@ import commonEvent from '@ohos.commonEvent'
// Attributes of a common event.
varoptions={
code:1,// Result code of the common event
data:"initial data",// Result data of the common event
data:"initial data";// Result data of the common event
}
```
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@@ -144,7 +144,7 @@ You can use the **unsubscribe** API to unsubscribe from a common event.
### Available APIs
| API | Description|
| ---------------------------------- | ------ |
| commonEvent.unsubscribe(subscriber: CommonEventSubscriber, callback?: AsyncCallback) | Unsubscribes from a common event.|
| unsubscribe(subscriber: CommonEventSubscriber, callback?: AsyncCallback) | Unsubscribes from a common event.|
@@ -7,16 +7,13 @@ Common Event Service (CES) enables applications to publish, subscribe to, and un
- System common event: sent by the system based on system policies to the applications that have subscribed to the event. This type of event includes the screen-on/off events that the users are aware of and the system events published by key system services, such as USB device attachment or detachment, network connection, and system update events.
- Custom common event: customized by applications to be received by specific subscribers. This type of event is usually related to the service logic of the sender applications.
The Advanced Notification Service (ANS) enables applications to publish notifications. Below are some typical use cases for publishing notifications:
- Display received SMS messages and instant messages.
- Display push messages of applications, such as advertisements, version updates, and news notifications.
The Advanced Notification Service (ANS) enables applications to publish notifications. Below are some typical use cases for publishing notifications:
- Display ongoing events, such as music playback, navigation information, and download progress.
- Display received SMS messages and instant messages.
- Display push messages of applications, such as advertisements, version updates, and news notifications.
- Display ongoing events, such as music playback, navigation information, and download progress.
Notifications are displayed in the notification panel. Uses can delete a notification or click the notification to trigger predefined actions.
**System API**: This is a system API and cannot be called by third-party applications.
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Event type.<br>- **"beginSleep"**: The screen enters sleep mode.<br>- **"endSleep"**: The screen exits sleep mode.<br>- **"changeUser"**: The user is switched.|
| callback | Callback\<number\> | Yes| Callback used to return the result. |
| parameter | number | Yes| Screen unlock status.<br>- **0**: The unlock is successful.<br>- **1**: The unlock failed.<br>- **2**: The unlock was canceled.|
| parameter | number | Yes| Screen unlock status.<br>- **0**: The unlock is successful.<br>- **1**: The unlock fails.<br>- **2**: The unlock is canceled.|
The **systemTime** module provides system time and time zone features. You can use the APIs of this module to set and obtain the system time and time zone.
> **NOTE**
>- The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>- The APIs of this module are system APIs and cannot be called by third-party applications.
>
> - The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.
## Modules to Import
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@@ -60,7 +60,7 @@ Sets the system time. This API uses a promise to return the result.
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------ |
| time | number | Yes | Timestamp to set, in milliseconds.|
| time | number | Yes | Timestamp to set, in milliseconds.|
**Return value**
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@@ -83,7 +83,7 @@ Sets the system time. This API uses a promise to return the result.
The **systemTimer** module provides system timer features. You can use the APIs of this module to implement the alarm clock and other timer services.
> **NOTE**<br/>
> **NOTE**
>- The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>- The APIs of this module are system APIs and cannot be called by third-party applications.
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@@ -25,11 +25,8 @@ Creates a timer. This API uses an asynchronous callback to return the result.
| options | TimerOptions | Yes | Timer options.<br>**TIMER_TYPE_REALTIME**: sets the timer to the real-time type. If it is not specified, the timer is of the non-real-time type.<br>**TIMER_TYPE_WAKEUP**: sets the timer to the wakeup type. If it is not specified, the timer is of the non-wakeup type.<br>**TIMER_TYPE_EXACT**: sets the timer to the exact type. If it is not specified, the timer is of the non-exact type.<br>**TIMER_TYPE_IDLE: number**: sets the timer to the idle type. If it is not specified, the timer is of the non-idle type (not yet supported).|
| repeat | boolean | Yes | Whether the timer is a repeating timer. The value **true** means that the timer is a repeating timer, and **false** means that the timer is a one-shot timer. |
| interval | number | No | Repeat interval. For a repeating timer, the value must be greater than 5000 ms. For a one-shot timer, the value is **0**. |
| wantAgent| wantAgent | No | **wantAgent** object of the notification to be sent when the timer expires. (An OpenHarmony application MainAbility can be started, but not an SA service.) |
| options | TimerOptions | Yes | Timer options.<br>**TIMER_TYPE_REALTIME**: sets the timer to the real-time type. If it is not specified, the timer is of the non-real-time type.<br>**TIMER_TYPE_WAKEUP**: sets the timer to the wakeup type. If it is not specified, the timer is of the non-wakeup type.<br>**TIMER_TYPE_EXACT**: sets the timer to the exact type. If it is not specified, the timer is of the non-exact type.<br>**TIMER_TYPE_IDLE: number**: sets the timer to the idle type. If it is not specified, the timer is of the non-idle type (not yet supported).|
| repeat | boolean | Yes | Whether the timer is a repeating timer. The value **true** means that the timer is a repeating timer, and **false** means that the timer is a one-shot timer. |
| interval | number | No | Repeat interval. For a repeating timer, the value must be greater than 5000 ms. For a one-shot timer, the value is **0**. |
| wantAgent| wantAgent | No | **wantAgent** object of the notification to be sent when the timer expires. (An OpenHarmony application MainAbility can be started, but not an SA service.) |
| type | number | Yes | **const TIMER_TYPE_REALTIME**: sets the timer to the CPU time type. If it is not specified, the timer is of the wall-time type.<br>**const TIMER_TYPE_WAKEUP**: sets the timer to the wakeup type. If it is not specified, the timer is of the non-wakeup type.<br>**const TIMER_TYPE_EXACT**: sets the timer to the exact type. If it is not specified, the timer is of the non-exact type.<br>**const TIMER_TYPE_IDLE: number**: sets the timer to the idle type. If it is not specified, the timer is of the non-idle type (not yet supported). |
| repeat | boolean | Yes | Whether the timer is a repeating timer. The value **true** means that the timer is a repeating timer, and **false** means that the timer is a one-shot timer. |
| interval | number | No | Repeat interval. For a repeating timer, the value must be greater than 5000 ms. For a one-shot timer, the value is **0**. |
| wantAgent| wantAgent | No | **wantAgent** object of the notification to be sent when the timer expires. (An application MainAbility can be started, but not a Service ability.) |
| callback | number | Yes | Callback used to return the timer ID. |
