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Android SQLite增刪改查

日期：2017/3/1 10:51:04 编辑：Linux編程

//目錄結構

//編寫DbOpenHelper.java類，繼承SQLiteOpenHelper

package sn.len.sqlite.service;
import Android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DbOpenHelper extends SQLiteOpenHelper
{
private static final String DATABASENAME="database.db";
private static final int DATABASVERSION=1;
public DbOpenHelper(Context context)
{
//實例化父類，創建數據庫
super(context, DATABASENAME, null, DATABASVERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL("create table sqlitetable(id integer primary key autoincrement,name varchar(20))");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
}
/*
*1.如果數據庫文件不存在，SQLiteOpenHelper在自動創建數據庫後會調用oncreate()方法，
*在該方法中一般需要創建表、視圖等組件。在創建前數據庫一般是空的，因此不需要先刪除數據庫中相關的組件。
*2.如果數據庫文件存在，並且當前版本號高於上次創建或升級的版本號，SQLiteOpenHelper會調用onUpdate()方法
*調用該方法後會更新數據庫的版本號。在onupdate()方法中除了創建表、視圖等組件外，還需要先刪除這些相關的組件，
*因此，在調用onupdate()方法前，數據庫是存在的，裡面還原許多數據庫組建。
*詳細了解:請看:http://hi.baidu.com/%C8%F4%CB%AA/blog/item/3d839c132e80353bdc54017b.html
* */
}

編寫bean Person.java

package sn.len.sqllite.domain;
public class Person
{
private Integer id;
private String name;
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 Person(Integer id, String name)
{
this.id = id;
this.name = name;
}
public Person()
{
}
@Override
public String toString()
{
return "Person [id=" + id + ", name=" + name + "]";
}
}

//編寫具體實現功能的service層PersonServic.java

package sn.len.sqlite.service;
import java.util.ArrayList;
import java.util.List;
import sn.len.sqllite.domain.Person;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
public class PersonService
{
//拿到SQLiteDatabase對象
private DbOpenHelper dbhelp;
public PersonService(Context context)
{
this.dbhelp=new DbOpenHelper(context);
}
//保存
public void save(Person person)
{
SQLiteDatabase dbopen=dbhelp.getWritableDatabase();
dbopen.execSQL("insert into sqlitetable(name) values(?)", new Object[]{person.getName()});
}
//刪除
public void del(Integer id)
{
SQLiteDatabase dbopen=dbhelp.getWritableDatabase();
dbopen.execSQL("delete from sqlitetable where id=?", new Object[]{id});
}
//更新
public void update(Person person)
{
SQLiteDatabase dbopen=dbhelp.getWritableDatabase();
dbopen.execSQL("update sqlitetable set name=? where id=?", new Object[]{person.getName(),person.getId()});
}
//查找
public Person select(Integer id)
{
SQLiteDatabase dbopen=dbhelp.getReadableDatabase();
Cursor cursor=dbopen.rawQuery("select * from sqlitetable where id=?",new String[]{id.toString()});
int db_id=cursor.getInt(cursor.getColumnIndex("id"));
String name=cursor.getString(cursor.getColumnIndex("name"));
return new Person(db_id,name);
}
//分頁
public List<Person> getScrollData(Integer offset,Integer maxResult)
{
List<Person> p=new ArrayList<Person>();
SQLiteDatabase dbopen=dbhelp.getReadableDatabase();
Cursor cursor=dbopen.rawQuery("select * from sqlitetable limit ?,?", new String[]{offset.toString(),maxResult.toString()});
while(cursor.moveToNext())
{
int id=cursor.getInt(cursor.getColumnIndex("id"));
String name=cursor.getString(cursor.getColumnIndex("name"));
Person persons=new Person(id,name);
p.add(persons);
}
cursor.close();
return p;
}
//得到總行數
public long getCount()
{
SQLiteDatabase dbopen=dbhelp.getReadableDatabase();
Cursor cusor=dbopen.rawQuery("select count(*) from sqlitetable", null);
cusor.moveToFirst();//不用判斷，不管有沒能結果都會返回一條記錄
long count=cusor.getLong(0);
return count;
}
//操作數據，基本都用execSQL();
//查詢數據，基本都用rawQuery();
}