android中传感器的学习
关于Sensor有关键的三个类：Sensor，SensorManger，SensorEventListener(是一个监听接口)
在Sensor类中可以看到android中定义的所有支持的传感器:
| Constants | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| int | TYPE_ACCELEROMETER | A constant describing an accelerometer sensor type. // 加速表传感器 | |||||||||
| int | TYPE_ALL | A constant describing all sensor types. // 周边温度传感器 api level 14以上支持 | |||||||||
| int | TYPE_AMBIENT_TEMPERATURE | A constant describing an ambient temperature sensor type // 温度传感器 | |||||||||
| int | TYPE_GRAVITY | A constant describing a gravity sensor type. // 重力传感器，api level 9以上支持 | |||||||||
| int | TYPE_GYROSCOPE | A constant describing a gyroscope sensor type // 陀螺仪传感器 | |||||||||
| int | TYPE_LIGHT | A constant describing an light sensor type. // 光线传感器 | |||||||||
| int | TYPE_LINEAR_ACCELERATION | A constant describing a linear acceleration sensor type. // 直线加速度传感器 api level 9以上支持 | |||||||||
| int | TYPE_MAGNETIC_FIELD | A constant describing a magnetic field sensor type. // 地磁传感器 | |||||||||
| int | TYPE_ORIENTATION | This constant is deprecated. use SensorManager.getOrientation() instead. |
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| int | TYPE_PRESSURE | A constant describing a pressure sensor type // 压力传感器 | |||||||||
| int | TYPE_PROXIMITY | A constant describing an proximity sensor type. // 近距传感器（打电话过程中结合光线传感器自动关闭屏幕使用） | |||||||||
| int | TYPE_RELATIVE_HUMIDITY | A constant describing a relative humidity sensor type. | |||||||||
| int | TYPE_ROTATION_VECTOR | A constant describing a rotation vector sensor type. | |||||||||
| int | TYPE_TEMPERATURE | This constant is deprecated. use Sensor.TYPE_AMBIENT_TEMPERATURE instead. // 温度传感器 |
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得到一个Sensor对象的步骤:
1.SensorManager sm = (SensorManager) getSystemService(SENSOR_SERVICE);
2.Sensor sensor = _sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); // 参数从上表中选择
注册SensorEvent监听器:
sm.registerListener(this, sensor, SensorManager.SENSOR_DELAY_GAME);
第二个参数是灵敏度，系统中定义了几个：
| int | SENSOR_DELAY_FASTEST | get sensor data as fast as possible |
| int | SENSOR_DELAY_GAME | rate suitable for games |
| int | SENSOR_DELAY_NORMAL | rate (default) suitable for screen orientation changes |
| int | SENSOR_DELAY_UI | rate suitable for the user interface |
注意：注册监听器后当程序不再需要监听时要取消监听，因为系统不会自动将其取消，这样对电池损耗很大，所以最好在onPause函数中取消监听。
