Update docs against 14433

Signed-off-by: wusongqing<wusongqing@huawei.com>

en/application-dev/device/Readme-EN.md

-# Device
+# Device Management
 
 - USB Service
   - [USB Service Overview](usb-overview.md)
@@ -17,3 +17,5 @@
 - Update Service
   - [Sample Server Overview](sample-server-overview.md)
   - [Sample Server Development](sample-server-guidelines.md)
+- Stationary
+  - [Stationary Development](stationary-guidelines.md)

en/application-dev/device/stationary-guidelines.md

+# Stationary Development
+
+
+## When to Use
+
+An application can call the **Stationary** module to obtain the device status, for example, whether the device is absolutely or relatively still.
+
+For details about the APIs, see [Stationary](../reference/apis/js-apis-stationary.md).
+
+## Device Status Type Parameters
+
+| Name| Description|
+| -------- | -------- |
+| still | Absolutely still.|
+| relativeStill | Relatively still.|
+
+## Parameters for Subscribing to Device Status events
+
+| 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.|
+
+## Returned Device Status Parameters
+
+| Name                            | Value   | Description                                      |
+| ------------------------------ | ---- | ---------------------------------------- |
+| ENTER         | 1    | Entering device status.  |
+| EXIT | 2   | Exiting device status.|
+
+## Available APIs
+
+| Module         | Name                                                      | Description                                                        |
+| ------------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
+| ohos.stationary | on(activity: ActivityType, event: ActivityEvent, reportLatencyNs: number, callback: Callback<ActivityResponse>): void | Subscribes to the device status. This API uses an asynchronous callback to return the result.|
+| ohos.stationary | once(activity: ActivityType, callback: Callback<ActivityResponse>): void | Obtains the device status. This API uses an asynchronous callback to return the result.|
+| ohos.stationary | off(activity: ActivityType, event: ActivityEvent, callback?: Callback<ActivityResponse>): void | Unsubscribes from the device status.                                |
+
+## Constraints
+
+The device must support the acceleration sensor.
+
+## How to Develop
+
+1. Subscribe to the event indicating entering the absolute still state, and the event is reported every 1 second.
+
+   ```js
+   import stationary from '@ohos.stationary';
+   var reportLatencyNs = 1000000000;
+   try {
+      stationary.on('still', stationary.ActivityEvent.ENTER, reportLatencyNs, (data) => {
+         console.log('data='+ JSON.stringify(data));
+      })
+   } catch (err) {
+      console.error('errCode: ' + err.code + ' ,msg: ' + err.message);
+   }
+   ```
+
+2. Obtain the event indicating entering the absolute still state.
+
+   ```js
+   import stationary from '@ohos.stationary';
+   try {
+      stationary.once('still', (data) => {
+         console.log('data='+ JSON.stringify(data));
+      })
+   } catch (err) {
+      console.error('errCode: ' + err.code + ' ,msg: ' + err.message);
+   }
+   ```
+
+3. Unsubscribe from the event indicating entering the absolute still state.
+
+   ```js
+   import stationary from '@ohos.stationary';
+   try {
+      stationary.off('still', stationary.ActivityEvent.ENTER, (data) => {
+         console.log('data='+ JSON.stringify(data));
+      })
+   } catch (err) {
+      console.error('errCode: ' + err.code + ' ,msg: ' + err.message);
+   }
+   ```