Geo tagging in android

Question

Camera.Parameters p = mCamera.getParameters();

p.setGpsLatitude(-81.626470);
p.setGpsLongitude(30.084970);
java.util.Date dt=new java.util.Date();
p.setGpsTimestamp(dt.getTime());
mCamera.setParameters(p);

The code above does not seem to geo tag the image.