//1数据库的增删查改,每次的操作都要打开数据库和关闭数据库.

//2在测试类中测试.注意在查询整个表的时候,因为要保存到一个集合里面,所以有个实体类.

//这是基本都是数据库操作语言db.execsql,db.rawQuery这两个方法.

package cn.itcast.db.dao;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.sqliteDatabase;
import android.util.Log;
import cn.itcast.db.MyDBOpenHelper;
import cn.itcast.db.domain.Person;

public class PersonDao {
	private static final String TAG = "PersonDao";
	private MyDBOpenHelper dbOpenHelper;

	// 在personDao被new出来的时候 就完成初始化

	public PersonDao(Context context) {
		dbOpenHelper = new MyDBOpenHelper(context);
		// dbOpenHelper.getReadableDatabase()
		// dbOpenHelper.getWritableDatabase()
	}

	// 增删改查

	/**
	 * 往数据库添加一条数据
	 */
	public void add(String name,String phone) {
		boolean result = find(name);
		if (result)
			return;

		sqliteDatabase db = dbOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			db.execsql("insert into person (name,phone) values (?,?)",new Object[] { name,phone });
			// 关闭数据库 释放数据库的链接
			db.close();
		}
	}

	/**
	 * 查找数据库的操作
	 */
	public boolean find(String name) {
		boolean result = false;
		sqliteDatabase db = dbOpenHelper.getReadableDatabase();
		if (db.isOpen()) {
			Cursor cursor = db.rawQuery("select * from person where name=?",new String[] { name });
			if (cursor.moveToFirst()) {
				int index = cursor.getColumnIndex("phone"); // 得到phone在表中是第几列
				String phone = cursor.getString(index);
				Log.i(TAG,"phone =" + phone);
				result = true;

			}
			// 记得关闭掉 cursor
			cursor.close();
			result = false;
			// 释放数据库的链接
			db.close();
		}
		return result;
	}

	/**
	 * 删除一条记录
	 * 
	 * @param name
	 */
	public void delete(String name) {
		sqliteDatabase db = dbOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			db.execsql("delete from person where name =?",new Object[] { name });
			db.close();
		}
	}

	/**
	 * 更新一条记录
	 * 
	 */
	public void update(String name,String newname,String newphone) {
		sqliteDatabase db = dbOpenHelper.getWritableDatabase();
		if (db.isOpen()) {
			db.execsql("update person set name=?,phone=? where name=?",new Object[] { newname,newphone,name });
			db.close();
		}
	}

	/**
	 * 查找全部,保存到list中.
	 */
	public List<Person> getAllPersons() {
		List<Person> persons=null;
		sqliteDatabase db = dbOpenHelper.getReadableDatabase();
		if (db.isOpen()) {
			persons = new ArrayList<Person>();
			Cursor cursor = db.rawQuery("select * from person ",null);
			while (cursor.moveToNext()) {
				Person person = new Person();
				int nameindex = cursor.getColumnIndex("name");
				int phoneindex = cursor.getColumnIndex("phone");
				String name = cursor.getString(nameindex);
				String phone = cursor.getString(phoneindex);
				person.setName(name);
				person.setNumber(phone);
				persons.add(person);
			}
			cursor.close();
			db.close();
		}
		return persons;
	}

}

<pre class="java" name="code">package cn.itcast.db.dao.test;

import java.util.List;

import cn.itcast.db.dao.PersonDao;
import cn.itcast.db.domain.Person;
import android.test.AndroidTestCase;

public class TestPersonDao extends AndroidTestCase {
	PersonDao dao;
	// 测试在执行测试代码时候的流程 
	//1 .new TestPersonDao 框架new出来 
	//2. 调用 setUp()
	//3. testAdd()  这个时候 上下文 才被创建出来 
	
	
/*	@Override
	protected void setUp() throws Exception {
		dao = new PersonDao(getContext());
		super.setUp();
	}*/
	public void testAdd() throws Exception{
		PersonDao dao = new PersonDao(getContext());
		for(int i=0;i<100;i++){
		dao.add("lisi"+i,"123456789"+i);
		}
	}
	public void testdelete() throws Exception{
		PersonDao dao = new PersonDao(getContext());
		dao.delete("lisi99");
	}
	public void testupdate() throws Exception{
		PersonDao dao = new PersonDao(getContext());
		dao.update("lisi98","wangwu","119");
	}
	
	public void testFindAll() throws Exception{
		PersonDao dao = new PersonDao(getContext());
		List<Person>  persons  = dao.getAllPersons();
		assertEquals(100,persons.size());
	}
 }

package cn.itcast.db.domain;

public class Person {
	String name;
	String number;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getNumber() {
		return number;
	}
	public void setNumber(String number) {
		this.number = number;
	}
	
}