Android 平台支持的位置传感器主要有三种: TYPE_MAGNETIC_FIELD。 TYPE_ORIENTATION。 TYPE_PROXIMITY。 下面对这三种传感器做简单介绍。 磁场传感器 磁场传感器用于测量地球磁场的强度。获取磁场
- TYPE_MAGNETIC_FIELD。
- TYPE_ORIENTATION。
- TYPE_PROXIMITY。
下面对这三种传感器做简单介绍。
磁场传感器
磁场传感器用于测量地球磁场的强度。获取磁场传感器实例的代码如下:private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);磁场传感器获取的原始数据记录的是在三个方向上地球磁场的强度。通常情况下,这些数据并不会直接使用,而是和旋转向量传感器、加速度传感器的数据一起用于计算设备的位置数据。
方位传感器
方位传感器用于监测设备相对于地球坐标系的位置。方位传感器从 Android 2.2(API Level 8)就被淘汰,在之后的设备上的访问传感器都是软件传感器。获取方位传感器实例的代码如下:
private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);以下代码演示了从方位传感器获取数据的过程:
public class SensorActivity extends Activity implements SensorEventListener { private SensorManager mSensorManager; private Sensor mOrientation; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); mOrientation = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION); } @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { // Do something here if sensor accuracy changes. // You must implement this callback in your code. } @Override protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mOrientation, SensorManager.SENSOR_DELAY_NORMAL); } @Override protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } @Override public void onSensorChanged(SensorEvent event) { float azimuth_angle = event.values[0]; float pitch_angle = event.values[1]; float roll_angle = event.values[2]; // Do something with these orientation angles. } }
距离传感器
距离传感器用于探测 Android 设备与其他物体的距离,例如手机与耳朵的距离。获取距离传感器实例的代码如下:private SensorManager mSensorManager; private Sensor mSensor; ... mSensorManager=(SensorManager)getSystemService(Context.SENSOR_SERVICE); mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);下列代码演示了使用距离传感器的方法:
public class SensorActivity extends Activity implements SensorEventListener { private SensorManager mSensorManager; private Sensor mProximity; @Override public final void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Get an instance of the sensor service, and use that to get an instance of // a particular sensor. mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } @Override public final void onAccuracyChanged(Sensor sensor, int accuracy) { // Do something here if sensor accuracy changes. } @Override public final void onSensorChanged(SensorEvent event) { float distance = event.values[0]; // Do something with this sensor data. } @Override protected void onResume() { // Register a listener for the sensor. super.onResume(); mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL); } @Override protected void onPause() { // Be sure to unregister the sensor when the activity pauses. super.onPause(); mSensorManager.unregisterListener(this); } }