增删改查操作 - 黑马程序员技术交流社区

package cn.itcast.service;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import cn.itcast.domain.Person;
public class OtherPersonService {
private DBOpenHelper dbOpenHelper;
public OtherPersonService(Context context) {
this.dbOpenHelper = new DBOpenHelper(context);
}
/**
* 添加记录
* @param person
*/
public void save(Person person){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("name", person.getName());
values.put("phone", person.getPhone());
values.put("amount", person.getAmount());
/*第二个参数为空值字段，当第三个参数为null或空时设置，不能设置为personid
db.execSQL("insert into person(name, phone, amount) values(?,?,?)",
new Object[]{person.getName(), person.getPhone(), person.getAmount()});
*/
db.insert("person", null, values);
}
/**
* 删除记录
* @param id 记录ID
*/
public void delete(Integer id){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
db.delete("person", "personid=?", new String[]{id.toString()});
//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();
ContentValues values = new ContentValues();
values.put("name", person.getName());
values.put("phone", person.getPhone());
values.put("amount", person.getAmount());
db.update("person", values, "personid=?", new String[]{person.getId().toString()});
//db.execSQL("update person set name=?,phone=?,amount=? where personid=?",
//new Object[]{person.getName(), person.getPhone(), person.getAmount(), person.getId()});
}
/**
* 查询记录
* @param id 记录ID
* @return
*/
public Person find(Integer id){
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
//第二个参数设为null表示获取虽有数据，等于new String[]{"name"+"phone"+"..."}
Cursor cursor = db.query("person", null, "personid=?", new String[]{id.toString()}, null, null, null);
//Cursor cursor = db.rawQuery("select * from person where personid=?", new String[]{id.toString()});
if(cursor.moveToFirst()){
int personid = cursor.getInt(cursor.getColumnIndex("personid"));
int amount = cursor.getInt(cursor.getColumnIndex("amount"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
return new Person(personid, name, phone, amount);
}
cursor.close();
return null;
}
/**
* 分页获取记录
* @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.query("person", null, null, null, null, null, "personid asc", offset+ ","+ maxResult);
//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"));
int amount = cursor.getInt(cursor.getColumnIndex("amount"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
persons.add(new Person(personid, name, phone, amount));
}
cursor.close();
return persons;
}
/**
* 获取记录总数
* @return
*/
public long getCount(){
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
Cursor cursor = db.query("person", new String[]{"count(*)"}, null, null, null, null, null);
// Cursor cursor = db.rawQuery("select count(*) from person", null);
cursor.moveToFirst();
long result = cursor.getLong(0);
cursor.close();
return result;
}
}

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