Bài giảng lập trình cho thiết bị di động chương 7 đh công nghệ đồng nai

DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors

2. Monitoring
the Battery

1


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors
The emulator does not provide any sensor data. All sensor testing must be done on a physical device.
Alternatively, OpenIntents.org also provides a handy Sensor Simulator: http://
code.google.com/p/openintents/wiki/SensorSimulator
This tool simulates accelerometer, compass, and temperature sensors, and it transmits data to the
emulator.

Android devices have a variety of sensors :

2


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors
TYPE_ACCELEROMETER: Measures acceleration in three directions; values are in SI units (m/s2).
TYPE_GYROSCOPE: Measures angular orientation in three directions; values are angles in degrees.
TYPE_LIGHT: Measures ambient light; values are in SI lux units.
TYPE_MAGNETIC_FIELD: Measures magnetism in three directions; the compass values are in micro-Tesla

(uT).
TYPE_PRESSURE: Measures barometric pressure.
TYPE_PROXIMITY: Measures the distance to an object; values are in centimeters, or “near” versus “far.”
TYPE_RELATIVE_HUMIDITY: Measures the relative humidity.
TYPE_AMBIENT_TEMPERATURE: Measures temperature.

3


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors

 Here are the major classes related to sensor.
Class

Comment

Sensor

Class representing a sensor. Use getSensorList(int) to get the list of available Sensors.

SensorEvent

This class represents a Sensor event and holds informations such as the sensor's type,
the time-stamp, accuracy and of course the sensor's data.

SensorEventListener

An interface: Used for receiving notifications from the SensorManager when sensor

values have changed.

SensorManager

SensorManager lets you access the device's sensors. Get an instance of this class by
calling Context.getSystemService() with the argument SENSOR_SERVICE.

4


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Working with Sensor

 To get a Sensor, you need to use SensorManager.

5


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Working with Sensor

 Register EventListener to it.

6


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Working with Sensor

 UnRegister EventListener.

Register in the onResume method and
Unregister in the onPause method

7


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



SensorManager.SENSOR_DELAY
Frequence

Comment

SENSOR_DELAY_FASTEST

get sensor data as fast as possible

SENSOR_DELAY_NORMAL

rate (default) suitable for screen orientation changes

SENSOR_DELAY_GAME

rate suitable for games

SENSOR_DELAY_UI

rate suitable for the user interface

8


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Receive SensorEvent
Normally, onSensorChanged is the method in which we need to put your sensor handle logic.

9


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



SensorEvent
Type

Name
public int accuracy

public Sensor sensor

public long timestamp

public final float[] values

Comment
The accuracy of this event.

The sensor that generated this event.

The time in nanosecond at which the event happened

The length and contents of the values array depends on

which sensor type is being monitored.

10


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_TEMPERATURE

11


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_TEMPERATURE

12


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_LIGHT

13


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_LIGHT

14


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_PRESSURE

15

DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_PRESSURE

16


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor. TYPE_PROXIMITY

17


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor. TYPE_PROXIMITY

18


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor. TYPE_PROXIMITY

19


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_ACCELEROMETER

2
The accelerometer values are represented in SI units (m/s ). The device at right has the bottom of the
2
device screen pointing toward the center of gravity. Gravity on Earth is 9.80665 m/s .

2
All values are in SI units (m/s )
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

20


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_ACCELEROMETER

Use to Accelerometer to detect SHAKING Device

21


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_ACCELEROMETER

22

DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_ACCELEROMETER

23


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_GYROSCOPE

measure, or maintain, the orientation of a device.
rate of rotation around a particular axis
values[0]: Angular speed around the x-axis
values[1]: Angular speed around the y-axis
values[2]: Angular speed around the z-axis

24


DONG NAI UNIVERSITY OF TECHNOLOGY

1. Sensors



Sensor.TYPE_GYROSCOPE

25