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.

Device Status Type Parameters

Parameters for Subscribing to Device Status events

Returned Device Status Parameters

Available APIs

Constraints

The device must support the acceleration sensor. Currently, only the algorithm framework is provided. The API test framework returns the following result: data={"type":3,"value":-1}. If the relative stationary and absolute stationary capabilities are required, you must implement them in device_status/libs/src/algorithm. The following code snippet is for reference:

algoPara_.resultantAcc =
   sqrt((algoPara_.x * algoPara_.x) + (algoPara_.y * algoPara_.y) + (algoPara_.z * algoPara_.z));
if ((algoPara_.resultantAcc > RESULTANT_ACC_LOW_THRHD) && (algoPara_.resultantAcc < RESULTANT_ACC_UP_THRHD)) {
   if (state_ == STILL) {
      return;
   }
   counter_--;
   if (counter_ == 0) {
      counter_ = COUNTER_THRESHOLD;
      UpdateStateAndReport(VALUE_ENTER, STILL, TYPE_ABSOLUTE_STILL);
   }
} else {
   counter_ = COUNTER_THRESHOLD;
   if (state_ == UNSTILL) {
      return;
   }
   UpdateStateAndReport(VALUE_EXIT, UNSTILL, TYPE_ABSOLUTE_STILL);
}

How to Develop

1. Subscribe to the event indicating entering the absolute still state, and the event is reported every 1 second.

   import { stationary } from '@kit.MultimodalAwarenessKit';
   import { BusinessError } from '@kit.BasicServicesKit';
   let reportLatencyNs = 1000000000;
   try {
      stationary.on('still', stationary.ActivityEvent.ENTER, reportLatencyNs, (data) => {
         console.log('data='+ JSON.stringify(data));
      })
   } catch (error) {
      let message = (error as BusinessError).message;
      console.error('stationary on failed:' + message);
   }
   

2. Obtain the event indicating entering the absolute still state.

   import { stationary } from '@kit.MultimodalAwarenessKit';
   import { BusinessError } from '@kit.BasicServicesKit';
   try {
      stationary.once('still', (data) => {
         console.log('data='+ JSON.stringify(data));
      })
   } catch (error) {
      let message = (error as BusinessError).message;
      console.error('stationary once failed:' + message);
   }
   

3. Unsubscribe from the event indicating entering the absolute still state.

   import { stationary } from '@kit.MultimodalAwarenessKit';
   import { BusinessError } from '@kit.BasicServicesKit';
   try {
      stationary.off('still', stationary.ActivityEvent.ENTER, (data) => {
         console.log('data='+ JSON.stringify(data));
      })
   } catch (error) {
      let message = (error as BusinessError).message;
      console.error('stationary off failed:' + message);
   }
   

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