一般后端

The generic sensor backend provides emulation of some of the sensors that are not supported on the platform. For example, on a platform without a rotation sensor but with an accelerometer, the accelerometer is used to calculate the rotation, thus providing an emulated rotation sensor.

The following generic sensors are supported:

Emulated Sensor Source Sensor
Ambient Light Sensor Light Sensor
Orientation Sensor Accelerometer
Rotation Sensor Accelerometer
Tilt Sensor Accelerometer

If a platform doesn't support the source sensor, then the sensor cannot be emulated.