android数据库简单操作

package com.example.dbtest.dbHelper;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

//继承SQLiteOpenHelper类
public class DbOpenHelper extends SQLiteOpenHelper {

public DbOpenHelper(Context context) {
//Context 上下文
//name 数据库名
//CursorFactory 游标工厂模式 当为null时 使用默认值
//version 数据库版本 版本号从1开始
super(context, "test.db", null, 1);
}

/**
* 第一次访问数据库 执行方法
* */
@Override
public void onCreate(SQLiteDatabase db) {
//创建表结构
String sql = "create table person(id integer primary key autoincrement,name varchar(20),age int,phone varchar(11))";
db.execSQL(sql);

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

}

package com.example.dbtest.domain;

public class Person {
private int id;
private String name;
private int age;
private String phone;

public Person(){}

public Person(int id, String name, int age, String phone) {
super();
this.id = id;
this.name = name;
this.age = age;
this.phone = phone;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}

@Override
public String toString() {
return "个人信息[id=" + id + ", name=" + name + ", age=" + age
+ ", phone=" + phone + "]";
}

}

package com.example.dbtest.dao;

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

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.example.dbtest.dbHelper.DbOpenHelper;
import com.example.dbtest.domain.Person;

public class PersonDao {

private DbOpenHelper helper;

public PersonDao(Context context)
{
helper = new DbOpenHelper(context);
}

//添加一条记录
public void add(Person p)
{
SQLiteDatabase db = helper.getWritableDatabase();
String sql = "insert into person(name,age,phone) values(?,?,?)";
db.execSQL(sql, new Object[]{p.getName(),p.getAge(),p.getPhone()});

}

//修改一条记录
public void update(Person p)
{
SQLiteDatabase db = helper.getWritableDatabase();
String sql = "update person set age=?,phone=? where name=?";
db.execSQL(sql, new Object[]{p.getAge(),p.getPhone(),p.getName()});

}

//删除一条记录
public void delete(String name)
{
SQLiteDatabase db = helper.getWritableDatabase();
String sql = "delete from person where name=?";
db.execSQL(sql,new Object[]{name});
}

public Person findByName(String name)
{

SQLiteDatabase db = helper.getReadableDatabase();
String sql = "select * from person where name=?";
Cursor cursor = db.rawQuery(sql, new String[]{name});
Person p = null;
while(cursor.moveToNext())
{
int id = cursor.getInt(cursor.getColumnIndex("id"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
int age = cursor.getInt(cursor.getColumnIndex("age"));
p = new Person(id,name,age,phone);
}
return p;
}

public List<Person> findAll(String name)
{

SQLiteDatabase db = helper.getReadableDatabase();
String sql = "select * from person where name=?";
Cursor cursor = db.rawQuery(sql, new String[]{name});
List<Person> list = new ArrayList();
while(cursor.moveToNext())
{
int id = cursor.getInt(cursor.getColumnIndex("id"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
int age = cursor.getInt(cursor.getColumnIndex("age"));
Person p = new Person(id,name,age,phone);
list.add(p);
}
return list;
}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.dbtest.MainActivity" >

<Button
android:id="@+id/btn_createDB"
android:onClick="createDB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="创建数据库" />

<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/btn_createDB"
android:layout_below="@+id/btn_createDB"
android:text="姓名" />

<EditText
android:id="@+id/et_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginLeft="21dp"
android:layout_marginTop="24dp"
android:ems="10"
/>

<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/btn_createDB"
android:layout_below="@+id/et_name"
android:text="电话" />

<EditText
android:id="@+id/et_phone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView2"
android:layout_below="@+id/textView2"
android:layout_marginLeft="21dp"
android:layout_marginTop="24dp"
android:ems="10"
/>

<Button
android:id="@+id/btn_save"
android:onClick="save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/et_phone"
android:text="保存" />
<Button
android:id="@+id/btn_update"
android:onClick="update"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/btn_save"
android:text="修改" />
<Button
android:id="@+id/btn_find"
android:onClick="findOne"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/btn_update"
android:text="查询" />
<Button
android:id="@+id/btn_delete"
android:onClick="delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/btn_find"
android:text="删除" />

</RelativeLayout>

package com.example.dbtest;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.text.TextUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import com.example.dbtest.dao.PersonDao;
import com.example.dbtest.dbHelper.DbOpenHelper;
import com.example.dbtest.domain.Person;

public class MainActivity extends ActionBarActivity {

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

public void createDB(View v)
{
DbOpenHelper db = new DbOpenHelper(this);
//该句才真正创建数据库
db.getWritableDatabase();
Toast.makeText(this, "数据库创建成功", 0).show();

}

public void save(View v)
{
EditText nameText = (EditText)this.findViewById(R.id.et_name);
EditText phoneText = (EditText)this.findViewById(R.id.et_phone);
String name = nameText.getText().toString();
String phone = phoneText.getText().toString();
if(TextUtils.isEmpty(name) || TextUtils.isEmpty(phone))
{
Toast.makeText(this, "姓名和电话不能为空", 0).show();
return;
}
PersonDao dao = new PersonDao(this);
Person p = new Person();
p.setName(name);
p.setPhone(phone);
dao.add(p);
Toast.makeText(this, "保存成功", 0).show();

}

public void update(View v)
{
EditText nameText = (EditText)this.findViewById(R.id.et_name);
EditText phoneText = (EditText)this.findViewById(R.id.et_phone);
String name = nameText.getText().toString();
String phone = phoneText.getText().toString();

PersonDao dao = new PersonDao(this);
Person p = new Person();
p.setName(name);
p.setPhone(phone);
dao.update(p);
Toast.makeText(this, "修改成功", 0).show();

}

public void delete(View v)
{
EditText nameText = (EditText)this.findViewById(R.id.et_name);
EditText phoneText = (EditText)this.findViewById(R.id.et_phone);
String name = nameText.getText().toString();
String phone = phoneText.getText().toString();

PersonDao dao = new PersonDao(this);
dao.delete(name);
Toast.makeText(this, "删除成功", 0).show();

}

}