Android中使用ormlite实现持久化(一)--HelloOrmLite

新建一个model：Hello.java

package cn.sdx.model;

 

import com.j256.ormlite.field.DatabaseField;

 

public class Hello {

@DatabaseField(generatedId = true)

int id;

@DatabaseField

String word;

 

public Hello() {

}

 

@Override

public String toString() {

  StringBuilder sb = new StringBuilder();

  sb.append("id=").append(id);

  sb.append(" ,word=").append(word);

  return sb.toString();

}

 

}

@DatabaseField是声明id为数据库字段，generatedId =true声明id为自增长

然后重写了toString()

 

再添加一个DataHelper.java

 

package cn.sdx.utils;

 

import java.sql.SQLException;

 

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.util.Log;

 

 

import cn.sdx.model.Hello;

 

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 DataHelper extends OrmLiteSqliteOpenHelper {

 

private static final String DATABASE_NAME = "HelloOrmlite.db";

private static final int DATABASE_VERSION = 1;

private Dao<Hello, Integer> helloDao = null;

 

public DataHelper(Context context) {

  super(context, DATABASE_NAME, null, DATABASE_VERSION);

}

 

@Override

public void onCreate(SQLiteDatabase db, ConnectionSource connectionSource) {

  try {

   TableUtils.createTable(connectionSource, Hello.class);

  } catch (SQLException e) {

   Log.e(DataHelper.class.getName(), "创建数据库失败", e);

   e.printStackTrace();

  }

}

 

@Override

public void onUpgrade(SQLiteDatabase db, ConnectionSource connectionSource, int arg2,

   int arg3) {

  try {

   TableUtils.dropTable(connectionSource, Hello.class, true);

   onCreate(db, connectionSource);

  } catch (SQLException e) {

   Log.e(DataHelper.class.getName(), "更新数据库失败", e);

   e.printStackTrace();

  }

}

 

@Override

public void close() {

  super.close();

  helloDao = null;

}

 

public Dao<Hello, Integer> getHelloDataDao() throws SQLException {

  if (helloDao == null) {

   helloDao = getDao(Hello.class);

  }

  return helloDao;

}

}

 

在布局文件中添加一个TextView

HelloOrmliteActivity.java中添加对数据库的操作

 

代码如下：

 

package cn.sdx;

 

import java.sql.SQLException;

import java.util.List;

 

import com.j256.ormlite.android.apptools.OrmLiteBaseActivity;

import com.j256.ormlite.dao.Dao;

 

import android.os.Bundle;

import android.widget.TextView;

import cn.sdx.model.Hello;

import cn.sdx.utils.DataHelper;

 

public class HelloOrmliteActivity extends OrmLiteBaseActivity<DataHelper> {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.main);

  TextView tv = (TextView) this.findViewById(R.id.output);

  try {

   Dao<Hello, Integer> helloDao = getHelper().getHelloDataDao();

   // 添加数据

   for (int i = 0; i < 2; i++) {

    Hello hello = new Hello("Hello" + i);

    helloDao.create(hello);

   }

   tv.setText(tv.getText() + "\n" + "添加数据完成");

   // 查询添加的数据

   List<Hello> hellos = helloDao.queryForAll();

   for (Hello h : hellos) {

    tv.setText(tv.getText() + "\n" + h.toString());

   }

   // 删除数据第一条数据

   helloDao.delete(hellos.get(0));

   tv.setText(tv.getText() + "\n" + "删除数据完成");

   // 重新查询数据

   hellos = helloDao.queryForAll();

   for (Hello h : hellos) {

    tv.setText(tv.getText() + "\n" + h.toString());

   }

   // 修改数据

   Hello h1 = hellos.get(0);

   h1.setWord("这是修改过的数据");

   tv.setText(tv.getText() + "\n" + "修改数据完成");

   helloDao.update(h1);

   // 重新查询数据

   hellos = helloDao.query

补充：移动开发 , Android ,