Android 数据存储之 SQLite嵌入式数据库

核心提示：// 仅演示用，所以先删除表然后再创建，Android 数据存储之 SQLite嵌入式数据库(4)，db.execSQL("DROP TABLE IF EXISTS contacts");this.onCreate(db);}}4.编写ContactsService类ContactsService类

// 仅演示用，所以先删除表然后再创建。

db.execSQL("DROP TABLE IF EXISTS contacts");

this.onCreate(db);

}

}

4.编写ContactsService类

ContactsService类主要实现对业务逻辑和数据库的操作。

package com.changcheng.sqlite.service;

import java.util.ArrayList;

import java.util.List;

import android.content.Context;

import android.database.Cursor;

import com.changcheng.sqlite.MyOpenHelper;

import com.changcheng.sqlite.entity.Contact;

public class ContactsService {

private MyOpenHelper openHelper;

public ContactsService(Context context) {

this.openHelper = new MyOpenHelper(context);

}

/**

* 保存

*

* @param contact

*/

public void save(Contact contact) {

String sql = "INSERT INTO contacts (name, phone) VALUES (?, ?)";

Object[] bindArgs = { contact.getName(), contact.getPhone() };

this.openHelper.getWritableDatabase().execSQL(sql, bindArgs);

}

/**

* 查找

*

* @param id

* @return

*/

public Contact find(Integer id) {

String sql = "SELECT _id,name, phone FROM contacts WHERE _id=?";

String[] selectionArgs = { id + "" };

Cursor cursor = this.openHelper.getReadableDatabase().rawQuery(sql,

selectionArgs);

if (cursor.moveToFirst())

return new Contact(cursor.getInt(0), cursor.getString(1), cursor

.getString(2));

return null;

}

/**

* 更新

*

* @param contact

*/

public void update(Contact contact) {

String sql = "UPDATE contacts SET name=?, phone=? WHERE _id=?";

Object[] bindArgs = { contact.getName(), contact.getPhone(),