private void recalculateProjectedCoordinates() {
        //update currentCoords and coordinate Views
        final Geopoint base = this.preprojectedCoords;

        final ProjectionType pType = this.projectionType.get();
        final boolean projectionEnabled = waypoint == null || (waypoint.isUserDefined() || waypoint.isOriginalCoordsEmpty());

        if (!projectionEnabled || pType == ProjectionType.NO_PROJECTION || base == null) {
            this.currentCoords = base;
        } else {
            this.currentCoords = calculateProjection(base);
        }
        ViewUtils.setCoordinates(base, binding.buttonLatLongitude);
        ViewUtils.setCoordinates(this.currentCoords, binding.projectedLatLongitude);
    }
this method assumes a correctly filled "preprojectedCoord"-var.
It recalculates the "currentCoord" value and updates view according to projection settings
main/src/main/java/cgeo/geocaching/EditWaypointActivity.java