数据库

<span style="font-size:18px;"></span><h2><span style="font-size:18px;">Person </span></h2>

<span style="font-size:18px;"></span>

<span style="font-size:18px;">package com.xh.tx.bean;public class Person {private Integer _id;private String name;private Integer age;public Integer get_id() {return _id;}public void set_id(Integer _id) {this._id = _id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Person() {super();// TODO Auto-generated constructor stub}public Person(Integer _id, String name, Integer age) {super();this._id = _id;this.name = name;this.age = age;}@Overridepublic String toString(){return "Person[_id=]"+_id+",name="+name+",age"+age+"]";}}</span>

PersonDao

<span style="font-size:18px;">package com.xh.tx.dao;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import com.xh.tx.SQLite.SQLite;import com.xh.tx.bean.Person;public class PersonDao {private SQLite helper;public PersonDao(Context context){helper=new SQLite(context,null,null,-1);}/** * 添加一个对象 * sql：insert into person(name,age)values('zs',20); * 缺陷：1、传递参数很麻烦 2、不能有返回值 */public void savePerson(Person p){String sql="insert into person(name,age)values(?,?);";SQLiteDatabase db=helper.getWritableDatabase();//db代表的是一个数据库的一个连接if(db.isOpen()){db.execSQL(sql, new Object[] {p.getName(),p.getAge()});db.close();}}/** *  删除一个对象 *  sql:delete from person where _id=1; */public void deletePerson(Integer id){String sql="delete from person where _id=?;";SQLiteDatabase db=helper.getWritableDatabase();if(db.isOpen()){db.execSQL(sql, new Integer[] {id});db.close();}}/** * 修改一个对象 * sql:update person set name='cccc' where _id=1; */public void updatePerson(Person p){String sql="update person set name=? where _id=?;";SQLiteDatabase db=helper.getWritableDatabase();if(db.isOpen()){db.execSQL(sql, new Object[] {p.getName(),p.get_id()});db.close();}}/** * 查询所有 * sql:select * from person; */public List<Person> queryPerson(){String sql="select _id,name,age from person;";SQLiteDatabase db=helper.getWritableDatabase();List<Person>list=null;if(db.isOpen()){Cursor cursor=db.rawQuery(sql, null);//查询//cursor.getCount()查看执行sql以后返回的结果集的个数if(cursor != null && cursor.getCount()>0){list=new ArrayList<Person>();while(cursor.moveToNext()){Integer id=cursor.getInt(0);String name=cursor.getString(1);Integer age=cursor.getInt(2);list.add(new Person(id,name,age));}}}return list;}}</span>

PersonDao1

<span style="font-size:18px;">package com.xh.tx.dao;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import com.xh.tx.SQLite.SQLite;import com.xh.tx.bean.Person;public class PersonDao1 {private static final String TAG = "PersonDao1";private SQLite helper;public PersonDao1(Context context){helper =new SQLite(context,null,null,-1);}//添加数据public void savePerson(Person p){SQLiteDatabase db=helper.getWritableDatabase();if(db.isOpen()){//nullColumnHack 如果数据库里面的name设计的时候不允许为空，但是你传递过来的参数是空，//如果不设置这个nullColumnHack参数那么就会报错//如果设置nullColumnHack这个参数的值为name那么不会报错ContentValues values = new ContentValues();values.put("name", p.getName());values.put("age", p.getAge());Long id=db.insert("person", null, values);Log.d(TAG,"=============:"+id);db.close();}}//删除数据public void deletePerson(Integer id){SQLiteDatabase db=helper.getWritableDatabase();if(db.isOpen()){String whereClause="_id=?";String [] whereArgs=new String []{String.valueOf(id)};int _id=db.delete("person", whereClause, whereArgs);Log.d(TAG, "===========:"+_id);db.close();}} //修改数据public void updatePerson(Person p){SQLiteDatabase db=helper.getWritableDatabase();if(db.isOpen()){ContentValues values=new ContentValues();values.put("name", "wtw");values.put("age", "2");String whereClause="_id=?";String [] whereArgs=new String []{String.valueOf(p.get_id())};db.update("person", values, whereClause, whereArgs);db.close();}}//public void queryItem(Integer id){SQLiteDatabase db=helper.getWritableDatabase();if(db.isOpen()){String [] columns=new String[]{"_id","name","age"};String selection="_id=?";String [] selectionArgs = new String []{String.valueOf(id)};String groupBy=null;//按什么什么分组String having =null;//如果select里面包含组函数的时候，不能用where去查询 就只能用havingString orderBy=null;//按什么排序 order by id desc；Cursor cursor =db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);if(null!= cursor && cursor.moveToFirst()){Integer _id=cursor.getInt(0);String name = cursor.getString(1);Integer age=cursor.getInt(2);Log.d(TAG,"_id="+_id+"name="+name+"age="+age);db.close();}}}} </span>

MainActivity

<span style="font-size:18px;">package com.xh.tx.SQLite;import android.app.Activity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings) {return true;}return super.onOptionsItemSelected(item);}}</span>

SQLite

<span style="font-size:18px;">package com.xh.tx.SQLite;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class SQLite extends SQLiteOpenHelper {/** * 函数的作用：构造方法用来创建工具类 * @param context 上下文环境 * @param name  数据库的名称 * @param factory  游标对象 Cursor * @param version   数据库的版本 不能从0开始 *  */public SQLite(Context context, String name, CursorFactory factory,int version) {super(context, "test.db", null, 1);}/** * 用来创建数据库 */@Overridepublic void onCreate(SQLiteDatabase db) {String sql="create table person(_id integer primary key,name varchar(20),age integer);";db.execSQL(sql);//真正执行数据的创建}//数据库版本更新@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}//每次打开数据库的时候调用@Overridepublic void onOpen(SQLiteDatabase db) {super.onOpen(db);}}</span>

TestDB

<span style="font-size:18px;">package com.xh.tx.test;import java.util.List;import com.xh.tx.SQLite.SQLite;import com.xh.tx.bean.Person;import com.xh.tx.dao.PersonDao;import android.test.AndroidTestCase;import android.util.Log;public class TestDB extends AndroidTestCase{private static final String TAG = "TestDB";public void testdb(){SQLite helper=new SQLite(getContext(),null,null,-1);helper.getWritableDatabase();}//添加数据public void testsavePerson(){Person p=new Person (1,"lisa",23);PersonDao dao=new PersonDao(getContext());dao.savePerson(p);}//删除数据public void testdeletePerson(){PersonDao dao=new PersonDao(getContext());dao.deletePerson(1);}//修改数据public void testupdatePerson(){Person p=new Person(1,"zhoujielun",36);PersonDao dao=new PersonDao(getContext());dao.updatePerson(p);}//public void testQuery(){PersonDao dao=new PersonDao(getContext());List<Person> list=dao.queryPerson();for(Person p:list){Log.d(TAG, p.toString());}}}</span>