将指南针指向特定位置

Question

我试图制作一个指向特定位置的指南针 我已经按照一些教程并在此处检查了之前的问题，但我没有得到正确的direction到目标

这是我的代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.compass_view);
    compassIcon = (ImageView) findViewById(R.id.imageViewCompass);
    sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    accelerometer = sensorManager
            .getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    magnetometer = sensorManager
            .getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);

    myLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

    currrentlocation = myLocationManager
            .getLastKnownLocation(LocationManager.GPS_PROVIDER);
    if (currrentlocation != null
            && currrentlocation.getTime() > Calendar.getInstance()
                    .getTimeInMillis() - 2 * 60 * 1000) {
        // get latitude and longitude values
        currentLatitude = currrentlocation.getLatitude();
        currentLongitude = currrentlocation.getLongitude();
        Log.d("myLocation at first ", currentLatitude + " "
                + currentLongitude);

    } else {
        myLocationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER, 1, 1, this);
    }
// target location 
    QiblaLocation = new Location("QiblaLocation");
    QiblaLocation.setLatitude(QiblaLatitude);
    QiblaLocation.setLongitude(QiblaLongitude);
}
@Override
protected void onResume() {
    super.onResume();
    // for the system's orientation sensor registered listeners
    sensorManager.registerListener(this, accelerometer,
            SensorManager.SENSOR_DELAY_UI);
    sensorManager.registerListener(this, magnetometer,
            SensorManager.SENSOR_DELAY_UI);

}

@Override
protected void onPause() {
    super.onPause();
    sensorManager.unregisterListener(this);
}
@Override
public void onSensorChanged(SensorEvent event) {
    // if (currrentlocation == null)
    // return;
        float[] mGravity = new float[3];
        float[] mGeomagnetic = new float[3];
        final float alpha = 0.97f;
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER)
            mGravity[0] = alpha * mGravity[0] + (1 - alpha)
                    * event.values[0];
        mGravity[1] = alpha * mGravity[1] + (1 - alpha) * event.values[1];
        mGravity[2] = alpha * mGravity[2] + (1 - alpha) * event.values[2];
        if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD)
            mGeomagnetic[0] = alpha * mGeomagnetic[0] + (1 - alpha)
                    * event.values[0];
        mGeomagnetic[1] = alpha * mGeomagnetic[1] + (1 - alpha)
                * event.values[1];
        mGeomagnetic[2] = alpha * mGeomagnetic[2] + (1 - alpha)
                * event.values[2];
        float R[] = new float[9];
        float I[] = new float[9];
        if (mGravity != null && mGeomagnetic != null) {
            boolean success = SensorManager.getRotationMatrix(R, I,
                    mGravity, mGeomagnetic);
            if (success) {
                float orientation[] = new float[3];
                SensorManager.getOrientation(R, orientation);
                azimuth = (float) Math.toDegrees(orientation[0]);
                // Log.d("first azimuth value"+String.valueOf(azimuth),null);
                calculateLocation();
            }
        }
    }

public void calculateLocation() {

    GeomagneticField geoField = new GeomagneticField(Double.valueOf(
            currrentlocation.getLatitude()).floatValue(), Double.valueOf(
            currrentlocation.getLongitude()).floatValue(), Double.valueOf(
            currrentlocation.getAltitude()).floatValue(),
            System.currentTimeMillis());

    azimuth -= geoField.getDeclination();
    Log.d("second azimuth", String.valueOf(azimuth));
    float bearTo = currrentlocation.bearingTo(QiblaLocation);

    if (bearTo < 0) {
        bearTo = bearTo + 360;
    }
    // point it
    float direction = bearTo - azimuth;
    if (direction < 0) {
        direction = direction + 360;
    }
    tvHeading.setText("Heading " + Float.toString(direction));

    RotateAnimation ra = new RotateAnimation(currentDegree, direction,
            Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
            0.5f);
    currentDegree = direction;
    ra.setDuration(1000);
    ra.setFillAfter(true);
    compassIcon.startAnimation(ra);
}
@Override
public void onLocationChanged(Location location) {
    currentLatitude = location.getLatitude();
    currentLongitude = location.getLongitude();
    location.setLatitude(currentLatitude);
    location.setLongitude(currentLongitude);
}