# @ohos.stationary (Device Status Awareness Framework)

The **stationary** module provides APIs to report the device status, including absolute still and relative still.

> **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.
>
> This module does not support x86 emulators.

## Modules to Import

```js
import stationary from '@ohos.stationary'
```

## ActivityResponse

Defines the response interface to receive the device status.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

### Attributes

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| state | [ActivityState](#activitystate) | Yes| No| New device status.|

## ActivityType

Enumerates the device status types.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

| Name| Description|
| -------- | -------- |
| still | Absolutely still.|
| relativeStill | Relatively still.|

## ActivityEvent

Enumerates the device status events.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

| Name                            | Value   | Description                                      |
| ------------------------------ | ---- | ---------------------------------------- |
| ENTER         | 1    | Event indicating entering device status.  |
| EXIT | 2   | Event indicating exiting device status.|
| ENTER_EXIT | 3   | Event indicating entering and exiting device status.|

## ActivityState

Enumerates the device statuses.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

| Name                            | Value   | Description                                      |
| ------------------------------ | ---- | ---------------------------------------- |
| ENTER         | 1    | Entering device status.  |
| EXIT | 2   | Exiting device status.|

## stationary.on('still' | 'relativeStill')

on(activity: ActivityType, event: ActivityEvent, reportLatencyNs: number, callback: Callback<ActivityResponse>): void

Subscribes to the device status.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

**Parameters**

| Name                 | Type                                              | Mandatory| Description                         |
| -------------------- | -------------------------------------------------- | ---- | ---------------------------- |
| activity  | [ActivityType](#activitytype)  | Yes  | Device status type.             |
| event  | [ActivityEvent](#activityevent)  | Yes  | Event type.             |
| reportLatencyNs  | number  | Yes  | Event reporting period.             |
| callback             | Callback<[ActivityResponse](#activityresponse)\>  | Yes  | Callback used to receive reported data.   |

**Example**

```js
var reportLatencyNs = 100;
stationary.on('still', stationary.ActivityEvent.ENTER, reportLatencyNs, (data) => {
    console.log('data='+ JSON.stringify(data));
})
```

## stationary.once('still' | 'relativeStill')

once(activity: ActivityType, callback: Callback&lt;ActivityResponse&gt;): void

Obtains the device status.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

**Parameters**

| Name                 | Type                                              | Mandatory| Description                         |
| -------------------- | -------------------------------------------------- | ---- | ---------------------------- |
| activity  | [ActivityType](#activitytype)  | Yes  | Device status type.             |
| callback             | Callback<[ActivityResponse](#activityresponse)\>  | Yes  | Callback used to receive reported data.   |

**Example**

```js
stationary.once('still', (data) => {
    console.log("data="+ JSON.stringify(data));
})
```

## stationary.off('still' | 'relativeStill')

off(activity: ActivityType, event: ActivityEvent, callback?: Callback&lt;ActivityResponse&gt;): void

Unsubscribes from the device status.

**System capability**: SystemCapability.Msdp.DeviceStatus.Stationary

**Parameters**

| Name                 | Type                                              | Mandatory| Description                         |
| -------------------- | -------------------------------------------------- | ---- | ---------------------------- |
| activity  | [ActivityType](#activitytype)  | Yes  | Device status type.             |
| event  | [ActivityEvent](#activityevent)  | Yes  | Event type.             |
| callback | Callback:\<[ActivityResponse](#activityresponse)>  | No  | Callback used to receive reported data, If the callback parameter is not passed or the type passed is undefined, all callbacks associated with the specified event in the process will be unregistered. |

**Example**

```js
stationary.off('still', stationary.ActivityEvent.ENTER);
```