SQLite存储和检索双值

Question

我想在数据库中存储和检索double值，但是当我插入纬度值时我遇到了一个问题，它完全插入但是当我检索纬度值时，它得到0.0意味着null ....下面的代码

import com.play.findnearplace.FD;


    public class Database extends SQLiteOpenHelper {
        protected static final int DATABASE_VERSION = 1;
        protected static final String DATABASE_NAME = "place";
        protected static final String TABLE_NAME = "tbl_place";

        public Database(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            String createdb = "CREATE TABLE IF NOT EXISTS "
                    + TABLE_NAME
                    + "(id INTEGER PRIMARY KEY AUTOINCREMENT,title VARCHAR NOT NULL ,description TEXT NOT NULL , refereceid TEXT NOT NULL ,place_id TEXT NOT NULL, delat DOUBLE ,delon DOUBLE)";
            db.execSQL(createdb);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO Auto-generated method stub
            db.execSQL("DROP TABLE IF NOT EXISTS " + TABLE_NAME);
            onCreate(db);
        }

        public void insertdata(String title,String decription,String refernce,String place_id,Double delat,Double delon){
            SQLiteDatabase db=getWritableDatabase();
            ContentValues v =new ContentValues();
            Logger.i("Query",refernce);
            v.put("title",title);
            v.put("description",decription);
            v.put("refereceid",refernce);
            v.put("place_id",place_id);
            v.put("delat",delat);//here value of delat="2252215.25"

            v.put("delon",delon);
            db.insert(TABLE_NAME,null, v);
            db.close();
        }

        public void isLikedelete(int id) {
            // TODO Auto-generated method stub
            SQLiteDatabase db = this.getWritableDatabase(); 
                    db.delete(TABLE_NAME, "id="+id, null);
                    db.close();         
        }

        public void isLikealldelete() {
            // TODO Auto-generated method stub
            SQLiteDatabase db = this.getWritableDatabase(); 
                    db.delete(TABLE_NAME,null, null);
                //db.execSQL("delete from "+ TABLE_NAME);
                    db.close();         
        }

        public void isLikeDeleteByRef(String place_id) {
            // TODO Auto-generated method stub

            SQLiteDatabase db = this.getWritableDatabase(); 

                    db.delete(TABLE_NAME, "place_id="+"'"+place_id+"'", null);
                    db.close();         
        }

        public List<FD> bookmarkdata(){
            SQLiteDatabase db=getReadableDatabase();
            List<FD> book=new ArrayList<FD>();
            String query="select * from "+ TABLE_NAME;
            Cursor c=db.rawQuery(query,null);


            if(c.moveToFirst()){
                do{
                    FD bookmark = new FD();
                    bookmark.setid(c.getInt(0));
                    bookmark.settitle(c.getString(1));
                    bookmark.setshort_title(c.getString(2));
                    bookmark.setreference(c.getString(3));
                    bookmark.setlat(c.getDouble(4));
                    bookmark.setlon(c.getDouble(5));
                    Logger.i("DAta",""+c.getDouble(4));//but here value getting c.getDouble(4)=0.0
                    book.add(bookmark);
                }while(c.moveToNext());
            }
            db.close();
            c.close();

            return book;
            }

        public boolean checkdataexist(String place_id){
            SQLiteDatabase db=getReadableDatabase();

            String query="select id from "+ TABLE_NAME +" where place_id='"+place_id+"'";
            Logger.i("Query",query);
            Cursor c=db.rawQuery(query,null);
            int count=c.getCount();
            boolean status;
            if (count==0){
                status= false;
            }else{
                status= true;
            }
            db.close();
            c.close();
            return status;
            }


    }

在insertdata（）方法中插入值很好，但是当我在bookmarkdata（）方法中检索纬度值时，它让我为空（0.0）这里有什么问题？