Cảm biến hướng Android

Question

là có thể biết hướng điện thoại đang trỏ đến khi xem trước máy ảnh hoặc bạn có để điện thoại phẳng như la bàn hay không.

Cảm ơn

Answer 1

Có - Các mã sau đây nên làm công việc

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); 
} 

}