安卓方向传感器

Question

是否可以在看相机预览时知道手机指向哪个方向，或者是否必须让手机像指南针一样平放。

感谢

Answer 1

是 - 下面的代码应该做的工作

public class Test extends Activity implements SensorEventListener{ 

public static float swRoll; 
public static float swPitch; 
public static float swAzimuth; 


public static SensorManager mSensorManager; 
public static Sensor accelerometer; 
public static Sensor magnetometer; 

public static float[] mAccelerometer = null; 
public static float[] mGeomagnetic = null; 


public void onAccuracyChanged(Sensor sensor, int accuracy) { 
} 

@Override 
public void onSensorChanged(SensorEvent event) { 
    // onSensorChanged gets called for each sensor so we have to remember the values 
    if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) { 
     mAccelerometer = event.values; 
    } 

    if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) { 
     mGeomagnetic = event.values; 
    } 

    if (mAccelerometer != null && mGeomagnetic != null) { 
     float R[] = new float[9]; 
     float I[] = new float[9]; 
     boolean success = SensorManager.getRotationMatrix(R, I, mAccelerometer, mGeomagnetic); 

     if (success) { 
      float orientation[] = new float[3]; 
      SensorManager.getOrientation(R, orientation); 
      // at this point, orientation contains the azimuth(direction), pitch and roll values. 
       double azimuth = 180 * orientation[0]/Math.PI; 
       double pitch = 180 * orientation[1]/Math.PI; 
       double roll = 180 * orientation[2]/Math.PI; 
     } 
    } 
} 



@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); 
    accelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); 
    magnetometer = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD); 
} 

@Override 
protected void onResume() { 
    super.onResume(); 

    mSensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_GAME); 
    mSensorManager.registerListener(this, magnetometer, SensorManager.SENSOR_DELAY_GAME); 
} 

@Override 
protected void onPause() { 
    super.onPause(); 
    mSensorManager.unregisterListener(this, accelerometer); 
    mSensorManager.unregisterListener(this, magnetometer); 
} 

}