Android : Android rotating arrow to GPS location

I'm implementing a feature in Android to point an arrow to a GPS location. According to this tutorial http://www.javacodegeeks.com/2013/09/android-compass-code-example.html . Originally, the code in the event onSensorChanged will point the Compass to the true north, now I have changed code in the event onSensorChanged to point to my GPS location like this:

@Override
public void onSensorChanged(SensorEvent event) {

    // get the angle around the z-axis rotated
    float degree = Math.round(event.values[0]);
    Location currentLoc = // get location from GPS or network
    GeomagneticField geoField = new GeomagneticField(
         (float) currentLoc.getLatitude(),
         (float) currentLoc.getLongitude(),
         (float) currentLoc.getAltitude(),
         System.currentTimeMillis());
    degree += geoField.getDeclination();

    tvHeading.setText("Heading: " + Float.toString(degree) + " degrees");

    // create a rotation animation (reverse turn degree degrees)
    RotateAnimation ra = new RotateAnimation(
            currentDegree, 
            -degree,
            Animation.RELATIVE_TO_SELF, 0.5f, 
            Animation.RELATIVE_TO_SELF,
            0.5f);

    // how long the animation will take place
    ra.setDuration(210);

    // set the animation after the end of the reservation status
    ra.setFillAfter(true);

    // Start the animation
    image.startAnimation(ra);
    currentDegree = -degree;

}

But after some test, it does not point to the correct place. Can anyone help me on this or explain what I have done wrong.

Thanks a lot.