实例教程六：创建数据库与完成数据添删改查--第一种写法

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cn.itcast.db"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<uses-library android:name="android.test.runner"/>
</application>
<instrumentation android:name="android.test.InstrumentationTestRunner"
android:targetPackage="cn.itcast.db" android:label="Tests for My App"></instrumentation>
</manifest>

package cn.itcast.db;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
//在Android平台上，集成了一个嵌入式关系型数据库——SQLite
//SQLite3支持NULL、INTEGER、REAL(浮点数字)、TEXT(字符串文本)和BLOB(二进制对象)数据类型
//虽然它支持的类型只有5种，但实际上sqlite3也接受varchar(n)、char(n)、decimal(p, s)等数据
//只不过在运行或保存时会转成对应的五种数据类型
//SQLite最大的特点是你可以把各种类型的数据保存到任何字段中，而不用关心字段声明的数据类型是什么
 
}

package cn.itcast.domain;
public class Person {
private Integer id;
private String name;
private String phone;
public Person(String name, String phone){
this.name = name;
this.phone = phone;
}
public Person(Integer id, String name, String phone){
this.id = id;
this.name = name;
this.phone = phone;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}        
}

package cn.itcast.service;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBOpenHelper extends SQLiteOpenHelper{
private static final int VERSION = 2; //数据库版本
public DBOpenHelper(Context context){
super(context, "itcast.db", null, VERSION); //<包>/database/
 
}
@Override
public void onCreate(SQLiteDatabase db) { //是在数据库第一次被创建的时候调用的
 
db.execSQL("CREATE TABLE person(personId integer primary key autoincrement, " + "name varchar(20))");                
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { //数据库版本号发生改变的时候调用的
                 db.execSQL("ALTER TABLE person ADD phone VARCHAR(12) NULL");
}
}

package cn.itcast.service;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import cn.itcast.domain.Person;
public class PersonService {
private DBOpenHelper dbOpenHelper;      
public PersonService(Context context){
this.dbOpenHelper = new DBOpenHelper(context); 
} 
/** 
* 添加记录 
* @param person 
*/
public void save(Person person){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase(); 
db.execSQL("insert into person(name, phone) values(?, ?)",new Object[]{person.getName(), person.getPhone()});
//如果只在一个类中使用db，则不需要关闭，提高性能
//但是若是多处使用，则需要关闭
//                db.close();
         } 
/**
* 删除记录 
* @param id 记录ID 
*/
public void delete(Integer id){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase(); 
db.execSQL("delete from person where personId=?", new Object[]{id});
}
/**
* 更新记录
* @param person
*/
public void update(Person person){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
db.execSQL("update person set name=?, phone=? where personId=?",
new Object[]{person.getName(), person.getPhone(), person.getId()});
}
/**
* 查询记录
* @param id 记录ID
* @return
*/
public Person find(Integer id){
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
Cursor cursor = db.rawQuery("select * from person where personId=?", new String[]{id.toString()});
if(cursor.moveToFirst()){
int personId = cursor.getInt(cursor.getColumnIndex("personId")); 
String name = cursor.getString(cursor.getColumnIndex("name")); 
String phone = cursor.getString(cursor.getColumnIndex("phone")); 
return new Person(personId, name, phone); 
}
cursor.close();               
return null; 
}
/**
* 分布获取记录 
* @param offset 跳过前面 多少条记录 
* @param maxResult 每页获取多少条记录 
* @return 
*/
public List<Person> getScrollData(int offset, int maxResult){
List<Person> persons = new ArrayList<Person>();
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
Cursor cursor = db.rawQuery("select * from person order by personId asc limit ?,?", 
new String[]{String.valueOf(offset), String.valueOf(maxResult)});
while(cursor.moveToNext()){
int personId = cursor.getInt(cursor.getColumnIndex("personId"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone")); 
persons.add(new Person(personId, name, phone));
}
cursor.close();
return null;
}
/**
* 获取记录总数
* @return
         */
public long getCount(){
SQLiteDatabase db = dbOpenHelper.getReadableDatabase(); 
Cursor cursor = db.rawQuery("select count(*) from person", null);
cursor.moveToFirst();
long result = cursor.getLong(0);
cursor.close(); 
return result;
}
}

package cn.itcast.test;
import java.util.List;
import cn.itcast.domain.Person; 
import cn.itcast.service.DBOpenHelper; 
import cn.itcast.service.PersonService; 
import android.test.AndroidTestCase; 
import android.util.Log;
public class PersonServiceTest extends AndroidTestCase{
private static final String TAG = "PersonServiceTest";
public void testCreateDB() throws Exception{
DBOpenHelper dbOpenHelper = new DBOpenHelper(getContext());
dbOpenHelper.getWritableDatabase(); 
}        
public void testSave() throws Exception{
PersonService service = new PersonService(this.getContext()); 
for(int i = 0; i < 20; i++){
Person person = new Person("zhangsan", "123456");
service.save(person);
}
}
public void testDelete() throws Exception{
PersonService service = new PersonService(this.getContext());
service.delete(21);
}
public void testUpdate() throws Exception{
PersonService service = new PersonService(this.getContext());
Person person = service.find(1);
person.setName("zhangxiaoxiao");
service.update(person);
}
public void testFind() throws Exception{
PersonService service = new PersonService(this.getContext());
Person person = service.find(1);
Log.i(TAG, person.toString());
}
public void testScrollData() throws Exception{
PersonService service = new PersonService(this.getContext());
List<Person> persons = service.getScrollData(0, 5);
for(Person person : persons){
Log.i(TAG, person.toString());
} 
}
public void testCount() throws Exception{
PersonService service = new PersonService(this.getContext());
long result = service.getCount();
Log.i(TAG, result + "");
}
//除了execSQL()和rawQuery方法，还提供了对应于添加、删除、更新、查询的操作方法
//insert(), delete(), update(), query()
 
}