working with sqliteopenhelper

MyDBHandler.java

public class MyDBHandler extends SQLiteOpenHelper {

    // ...existing methods...

  public static class StudentDetailCursor extends SQLiteCursor {
    /** The query for this cursor */
    private static final String QUERY =
        "SELECT _id, _studentname, _phone, _address, lat, lng, zom FROM students ";
    /** Cursor constructor */
    private StudentDetailCursor(SQLiteDatabase db, SQLiteCursorDriver driver,
            String editTable, SQLiteQuery query) {
        super(db, driver, editTable, query);
    }
    /** Private factory class necessary for rawQueryWithFactory() call */
    private static class Factory implements SQLiteDatabase.CursorFactory{
        @Override
        public Cursor newCursor(SQLiteDatabase db,
                SQLiteCursorDriver driver, String editTable,
                SQLiteQuery query) {
            return new StudentDetailCursor(db, driver, editTable, query);
        }
    }
    /* Accessor functions -- one per database column */
    public long getColStudentsId() {
        return getLong(getColumnIndexOrThrow("_id"));
    }
    public String getColPhone() {
        return getString(getColumnIndexOrThrow("_phone"));
    }
    public String getColAddress(){
        return getString(getColumnIndexOrThrow("_address"));
    }
    public long getColLatitude() {
        return getLong(getColumnIndexOrThrow("lat"));
    }
    public long getColLongitude() {
        return getLong(getColumnIndexOrThrow("lng"));
    }
    public long getColZoom() {
        return getLong(getColumnIndexOrThrow("zom"));
    }
}

/** Returns a Student for the specified studentID
 * @param studentID The _id of the student
 */
public StudentDetailCursor getStudentDetails(String studentID) {
    String sql = StudentDetailCursor.QUERY + studentID;
    SQLiteDatabase d = getReadableDatabase();
    StudentDetailCursor c = (StudentDetailCursor)
        d.rawQueryWithFactory(
        new StudentDetailCursor.Factory(),
        sql,
        null,
        null);
    c.moveToFirst();
    return c;
}
}

XActivity.java

private MyDBHandler.StudentDetailCursor student;
MyDBHandler db;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    db = new MyDBHandler(this);
    student = db.getStudentDetails(student_id);

    student_lng = student.getColLongitude
    student_lat = student.getColLatitude

    double lng = Double.parseDouble(student_lng);
    double lat = Double.parseDouble(student_lat);
}