OrmLite数据库的使用方法

public class DataBaseHelper extends OrmLiteSqliteOpenHelper {
private static final String DB_NAME="biying.db";
private static final int DB_VERSON=1;
private DataBaseHelper(Context mContext){
super(mContext,DB_NAME,null,DB_VERSON);
    }
/**
     * 基本单例模式:
     *  1、先把构造函数私有化
*  2、对外提供一个静态方法
*  3、在方法中判断如果已经存在就不再创建，如果不存在再创建
*  这样保证永远只有一个DataBaseHelper对象
*  4、为了线程安全，需要在方法前提供一个线程安全关键字synchronized
     *  如果一个调用时，另一个就不允许调用
*/
private static DataBaseHelper dataBaseHelper;
public synchronized static DataBaseHelper getInstance(Context mContext){
if (dataBaseHelper == null) {
dataBaseHelper = new DataBaseHelper(mContext);
        }
return dataBaseHelper;
    }

@Override
public void onCreate(SQLiteDatabase sqLiteDatabase, ConnectionSource connectionSource) {
//创建表
try {
//CardImg
TableUtils.createTableIfNotExists(connectionSource, CardImg.class);

        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, ConnectionSource connectionSource, int i, int i1) {
//删除表
try {
            TableUtils.dropTable(connectionSource,CardImg.class,true);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

}

package com.jereh.biyingapplication.dao;

import android.content.Context;

import com.j256.ormlite.dao.Dao;
import com.j256.ormlite.stmt.DeleteBuilder;
import com.jereh.biyingapplication.db.DataBaseHelper;
import com.jereh.biyingapplication.entity.CardImg;
import com.jereh.biyingapplication.entity.Images;

import java.sql.SQLException;
import java.util.List;

/**
 * Created by zhangdi on 2016/8/31.
 */
public class CardImgDao {
private Dao<CardImg,Integer> cardImgDao;
public CardImgDao(Context mContext){
        DataBaseHelper dataBaseHelper = DataBaseHelper.getInstance(mContext);
try {
cardImgDao = dataBaseHelper.getDao(CardImg.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

/**
     * 添加一条数据，一个对象
* @param cardImg
* @return
*/
public long addCardImg(CardImg cardImg){
int id =0;
try {
            id = cardImgDao.create(cardImg);
        } catch (SQLException e) {
            e.printStackTrace();
        }
return id;
    }

public void addAll(List<CardImg> images){
for (CardImg img:images){
            addCardImg(img);
        }
    }
/**
     * 查询表中所有属性
* @return  表的集合
*/
public List<CardImg> findAll(){
try {
return cardImgDao.queryForAll();
        } catch (SQLException e) {
            e.printStackTrace();
        }
return null;
    }
/**
     * 根据对象删除某条数据
* @param cardImg
*/
public void delete(CardImg cardImg){
        DeleteBuilder deleteBuilder = cardImgDao.deleteBuilder();
try {
            deleteBuilder.where().eq("img",cardImg.getImg());
            deleteBuilder.delete();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

/**
     * 删除所有数据
* @param images
*/
public void removeAll(List<CardImg> images){
for (CardImg img:images){
            delete(img);
        }
    }
}