Android菜鸟成长记12 -- ORMLite的简单使用

　　在我们的开发中，为了提高开发效率，我们一般都会使用到框架，ormilte则是我们必不可少的数据库框架。

　　对于ORMLite我也是今天才刚刚接触，我们先从一个简单的项目来了解它吧。

ORMLite jar

　　要想使用ormlite，我们要先下载其jar包。

　　下载方法：

　　　　我们可以到官网去下载：http://ormlite.com/releases/

　　　　下载的时候，我们要下载一个core的jar和android的jar，本人用的是ormlite-android-5.0.jar和ormlite-core-5.0.jar

　　　　然后把我们下载好的jar放在我项目中的lib下，然后加载到项目中即可

　　　

编写Bean类

 package com.example.bean;

 import com.j256.ormlite.field.DatabaseField;
 import com.j256.ormlite.table.DatabaseTable;

 @DatabaseTable(tableName="t_student")
 public class student {

     //generatedId表示该字段名为主键，却自增长
     @DatabaseField(generatedId=true)
     private int stuId;
     @DatabaseField(columnName="stuName")
     private String stuName;
     @DatabaseField(columnName="age")
     private int age;
     public int getStuId() {
         return stuId;
     }
     public void setStuId(int stuId) {
         this.stuId = stuId;
     }
     public String getStuName() {
         return stuName;
     }
     public void setStuName(String stuName) {
         this.stuName = stuName;
     }
     public int getAge() {
         return age;
     }
     public void setAge(int age) {
         this.age = age;
     }

 }

@DatabaseTable(tableName = "tb_user")，标明这是数据库中的一张表

@DatabaseField(columnName = "name") ，columnName的值为该字段在数据中的列名

@DatabaseField(generatedId = true) ，generatedId 表示id为主键且自动生成

编写ORMilte的dao包

package com.example.ormlitetest;

import java.sql.SQLException;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.util.Log;

import com.example.bean.student;
import com.j256.ormlite.android.apptools.OrmLiteSqliteOpenHelper;
import com.j256.ormlite.dao.Dao;
import com.j256.ormlite.support.ConnectionSource;
import com.j256.ormlite.table.TableUtils;

public class DataBaseHelp extends OrmLiteSqliteOpenHelper{

    private static final int version = ;
    private static final String DB_NAME = "text_data.db";
    //每张表对应一个
    private Dao<student,Integer> studao ;

    public Dao<student,Integer> getDao() throws SQLException{
        if(studao == null){
            studao = getDao(student.class);
        }
        return studao;
    }

    public DataBaseHelp(Context context) {
        super(context, DB_NAME, null, version);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db, ConnectionSource connectionSource) {
        try {
            TableUtils.createTable(connectionSource, student.class);
            Log.i("tag", "创建数据库success");
        } catch (Exception e) {
            Log.i("tag", "错误");
        }

    }

    @Override
    public void onUpgrade(SQLiteDatabase arg0, ConnectionSource arg1, int arg2,
            int arg3) {
        // TODO Auto-generated method stub

    }

    @Override
    public void close() {
        // TODO Auto-generated method stub
        super.close();
        studao = null;
    }

}

这里我们需要继承OrmLiteSqliteOpenHelper，其实就是间接继承了SQLiteOpenHelper

然后需要实现两个方法：

1、onCreate(SQLiteDatabase database,ConnectionSource connectionSource)

创建表，我们直接使用ormlite提供的TableUtils.createTable(connectionSource, User.class);进行创建~

2、onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion)

更新表，使用ormlite提供的TableUtils.dropTable(connectionSource, User.class, true);进行删除操作~

删除完成后，别忘了，创建操作：onCreate(database, connectionSource);

MainActivity类通用数据库

 package com.example.ormlitetest;

 import java.sql.SQLException;
 import java.util.*;

 import com.example.bean.student;

 import android.app.Activity;
 import android.database.sqlite.SQLiteDatabase;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.BaseAdapter;
 import android.widget.ListView;
 import android.widget.TextView;

 public class MainActivity extends Activity {

     private SQLiteDatabase db;
     private ListView lv;
     private List<student> stulist = new ArrayList<student>();

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         DataBaseHelp help = new DataBaseHelp(MainActivity.this);

         for (int i = ; i < ; i++) {
             student s = new student();
             s.setStuName("好无聊" + i);
             s.setAge(i);
             try {
                 help.getDao().create(s);
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         try {
             stulist = help.getDao().queryForAll();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         lv = (ListView) findViewById(R.id.listView1);
         lv.setAdapter(new BaseAdapter() {

             public View getView(int position, View convertView, ViewGroup parent) {
                 View view = null;
                 if (convertView == null) {
                     Log.i("info:", "没有缓存，重新生成" + position);
                     LayoutInflater inflater = MainActivity.this
                             .getLayoutInflater();
                     // 因为getView()返回的对象，adapter会自动赋给ListView
                     view = inflater
                             .inflate(R.layout.list_item, null);
                 } else {
                     Log.i("info:", "有缓存，不需要重新生成" + position);
                     view = convertView;
                 }
                 student s = stulist.get(position);

                 TextView tv_userName = (TextView) view
                         .findViewById(R.id.tv_stuName);
                 tv_userName.setText(s.getStuName());
                 tv_userName.setTextSize();

                 TextView tv_lastMessage = (TextView) view
                         .findViewById(R.id.tv_age);
                 tv_lastMessage.setText(s.getAge()+"");
                 tv_lastMessage.setTextSize();

                 return view;
             }

             @Override
             public long getItemId(int arg0) {
                 // TODO Auto-generated method stub
                 return ;
             }

             @Override
             public Object getItem(int arg0) {
                 // TODO Auto-generated method stub
                 return null;
             }

             @Override
             public int getCount() {
                 // TODO Auto-generated method stub
                 return stulist.size();
             }
         });
         help.close();
     }

 }

然后我们运行一下程序看一下

好了， 这就是本人对于ORMLite的初步了解。