SensorEvent

extends Object

java.lang.Object
↳	android.hardware.SensorEvent

Class Overview

This class represents a sensor event and holds informations such as the sensor type (eg: accelerometer, orientation, etc...), the time-stamp, accuracy and of course the sensor's data.

Definition of the coordinate system used by the SensorEvent API.

 The coordinate space is defined relative to the screen of the phone 
 in its default orientation. The axes are not swapped when the device's
 screen orientation changes.
 
 The OpenGL ES coordinate system is used. The origin is in the
 lower-left corner  with respect to the screen, with the X axis horizontal
 and pointing  right, the Y axis vertical and pointing up and the Z axis
 pointing outside the front face of the screen. In this system, coordinates
 behind the screen have negative Z values.
 
 Note: This coordinate system is different from the one used in the
 Android 2D APIs where the origin is in the top-left corner. 

   x<0         x>0
                ^
                |
    +-----------+-->  y>0
    |           |
    |           |
    |           |
    |           |   / z<0
    |           |  /
    |           | /
    O-----------+/
    |[]  [ ]  []/
    +----------/+     y<0
              /
             /
           |/ z>0 (toward the sky)

    O: Origin (x=0,y=0,z=0)

Summary

Fields
public int	accuracy	The accuracy of this event.
public Sensor	sensor	The sensor that generated this event.
public long	timestamp	The time in nanosecond at which the event happened
public final float[]	values	The length and contents of the values array vary depending on which sensor type is being monitored (see also SensorEvent for a definition of the coordinate system used): Sensor.TYPE_ORIENTATION: All values are angles in degrees.

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Inherited Methods

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Is called before the object's memory is being reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of Class which represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.

Fields

public int accuracy

The accuracy of this event. See SensorManager for details.

public Sensor sensor

The sensor that generated this event. See SensorManager for details.

public long timestamp

The time in nanosecond at which the event happened

public final float[] values

The length and contents of the values array vary depending on which sensor type is being monitored (see also SensorEvent for a definition of the coordinate system used):

Sensor.TYPE_ORIENTATION:

All values are angles in degrees.

values[0]: Azimuth, angle between the magnetic north direction and the Y axis, around the Z axis (0 to 359). 0=North, 90=East, 180=South, 270=West

values[1]: Pitch, rotation around X axis (-180 to 180), with positive values when the z-axis moves toward the y-axis.

values[2]: Roll, rotation around Y axis (-90 to 90), with positive values when the x-axis moves away from the z-axis.

Note: This definition is different from yaw, pitch and roll used in aviation where the X axis is along the long side of the plane (tail to nose).

Note: It is preferable to use getRotationMatrix() in conjunction with remapCoordinateSystem() and getOrientation() to compute these values; while it may be more expensive, it is usually more accurate.

Sensor.TYPE_ACCELEROMETER:

All values are in SI units (m/s^2) and measure the acceleration applied to the phone minus the force of gravity.

values[0]: Acceleration minus Gx on the x-axis

values[1]: Acceleration minus Gy on the y-axis

values[2]: Acceleration minus Gz on the z-axis

Examples:

When the device lies flat on a table and is pushed on its left side toward the right, the x acceleration value is positive.

When the device lies flat on a table, the acceleration value is +9.81, which correspond to the acceleration of the device (0 m/s^2) minus the force of gravity (-9.81 m/s^2).

When the device lies flat on a table and is pushed toward the sky with an acceleration of A m/s^2, the acceleration value is equal to A+9.81 which correspond to the acceleration of the device (+A m/s^2) minus the force of gravity (-9.81 m/s^2).

Sensor.TYPE_MAGNETIC_FIELD:

All values are in micro-Tesla (uT) and measure the ambient magnetic field in the X, Y and Z axis.

Interfaces

Classes