en/devices/sensors/interaction.html

page.title=Interaction
@jd:body

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<p>From the perspective of Android applications, every Android sensor is an
  independent entity, meaning there is no interaction between the different
  sensors.</p>
<ul>
  <li> This is true even though several Android sensors might share the same
    underlying physical sensor </li>
  <li> For example: step counter, significant motion and accelerometer, all relying on
    the same physical accelerometer, must be able to work concurrently </li>
  <li> This is also true for wake-up and non-wake-up versions of the same sensor </li>
</ul>
<p>Android sensors must be able to work simultaneously and independently of one
  another. That is, any action on one Android sensor must not impact the behavior
  of the other sensors.</p>
<p>Specifically, at the HAL level:</p>
<ul>
  <li> activating a sensor </li>
  <li> deactivating a sensor </li>
  <li> changing the sampling frequency of a sensor </li>
  <li> changing the maximum reporting latency of a sensor </li>
</ul>
<p>cannot cause:</p>
<ul>
  <li> another activated sensor to stop working </li>
  <li> another activated sensor to change sampling rate </li>
  <li> another activated sensor to decrease the quality of its measurements </li>
  <li> another non-activated sensor to start delivering events </li>
</ul>
<p>Nor can any of the actions above prevent actions (activation, deactivation,
  and parameter changes) on another sensor from succeeding. For instance,
  whether we can activate the step counter must be independent of whether the
  accelerometer is currently activated. </p>
<p>As another important example, a wake-up sensor activated at 5Hz must generate events
  at around 5Hz, even if its non-wake-up variant is being activated at 100Hz.</p>