isWakeUpSensor property

bool? isWakeUpSensor
final

Returns true if the sensor is a wake-up sensor.

Application Processor Power modes

Application Processor(AP), is the processor on which applications run. When no wake lock is held and the user is not interacting with the device, this processor can enter a “Suspend” mode, reducing the power consumption by 10 times or more.

Non-wake-up sensors

Non-wake-up sensors are sensors that do not wake the AP out of suspend to report data. While the AP is in suspend mode, the sensors continue to function and generate events, which are put in a hardware FIFO. The events in the FIFO are delivered to the application when the AP wakes up. If the FIFO was too small to store all events generated while the AP was in suspend mode, the older events are lost: the oldest data is dropped to accommodate the newer data. In the extreme case where the FIFO is non-existent {@code maxFifoEventCount() == 0}, all events generated while the AP was in suspend mode are lost. Applications using non-wake-up sensors should usually:

  • Either unregister from the sensors when they do not need them, usually in the activity’s {@code onPause} method. This is the most common case.
  • Or realize that the sensors are consuming some power while the AP is in suspend mode and that even then, some events might be lost.

Wake-up sensors

In opposition to non-wake-up sensors, wake-up sensors ensure that their data is delivered independently of the state of the AP. While the AP is awake, the wake-up sensors behave like non-wake-up-sensors. When the AP is asleep, wake-up sensors wake up the AP to deliver events. That is, the AP will wake up and the sensor will deliver the events before the maximum reporting latency is elapsed or the hardware FIFO gets full. See {@link SensorManager#registerListener(SensorEventListener, Sensor, int, int)} for more details.

@return true if this is a wake-up sensor, false otherwise.

Implementation

final bool? isWakeUpSensor;