android——查詢所有，查詢個數、查詢分頁

1、PersonDao

完整版的PersonDao的代碼如下：

package com.njupt.sqllist;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;public class PersonDao {DBOpenHelper helper ;public PersonDao(Context context){helper = new DBOpenHelper(context);}public void insert(Person p){SQLiteDatabase db = helper.getWritableDatabase();db.execSQL("insert into person(name,balance) values(?,?)", new Object[]{ p.getName(),p.getBalance()});    db.close();}public void delete(int id){SQLiteDatabase db = helper.getWritableDatabase();db.execSQL("delete from person where id = ?", new Object[]{id});db.close();}public void update(Person p){SQLiteDatabase db = helper.getWritableDatabase();db.execSQL("update person set name = ? , balance = ? where id = ? ", new Object[]{p.getName(),p.getBalance(),p.getId()});}public Person query(int id){SQLiteDatabase db = helper.getReadableDatabase();Cursor c = db.rawQuery("select name , balance from person where id = ?", new String[]{id + ""});    Person p = null ;if(c.moveToNext()){String name = c.getString(c.getColumnIndex("name"));int balance = c.getInt(1);p = new Person(id,name,balance);}return p;}public List<Person> queryAll(){SQLiteDatabase db = helper.getReadableDatabase();Cursor c = db.rawQuery("select * from person", null);List<Person> persons = new ArrayList<Person>();while(c.moveToNext()){Person p = new Person(c.getInt(0),c.getString(1),c.getInt(2));persons.add(p);}return persons;}public int queryCount(){SQLiteDatabase db = helper.getReadableDatabase();Cursor c = db.rawQuery("select count(*) from person", null); c.moveToNext();  int count = c.getInt(0); return count;}public List<Person> queryPage(int pageNum , int pageSize){SQLiteDatabase db = helper.getReadableDatabase();Cursor c = db.rawQuery("select * from person limit ?,?", new String[]{(pageNum - 1)*pageSize + "",pageSize + ""  });List<Person> persons = new ArrayList<Person>();while(c.moveToNext()){Person p = new Person(c.getInt(0),c.getString(1),c.getInt(2));persons.add(p);}return persons;}}

2、DBTest

以下附上完整版的測試代碼：

package com.njupt.sqllist;import java.util.List;import java.util.Random;import android.test.AndroidTestCase;public class DBTest extends AndroidTestCase{public void test1(){DBOpenHelper helper = new DBOpenHelper(getContext());helper.getWritableDatabase();}public void testInsert(){PersonDao dao = new PersonDao(getContext());    Random r = new Random(40000);    for(int i = 0 ; i < 100 ; ++i ){Person p = new Person(0,"Test"+ i ,r.nextInt());dao.insert(p);}}public void testDelete(){PersonDao dao = new PersonDao(getContext());    dao.delete(1);}public void testUpdate(){PersonDao dao = new PersonDao(getContext());Person p = new Person(2,"劉亦菲",45000);dao.update(p);}public void testQuery(){PersonDao dao = new PersonDao(getContext());Person p = dao.query(3);System.out.println(p);}public void testQueryAll(){PersonDao dao = new PersonDao(getContext());List<Person> persons = dao.queryAll();    for(Person p : persons){System.out.println(p);}}public void testQueryCount(){PersonDao dao = new PersonDao(getContext());int count = dao.queryCount();System.out.println(count);}public void testQueryPage(){PersonDao dao = new PersonDao(getContext());List<Person> persons = dao.queryPage(2, 10);for(Person p : persons){System.out.println(p);}}}

===============================================

分頁的結果如下所示：

查詢總數：