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        //factory 数据库工厂 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();            }}