Android SQLiteDatabase的使用

需要實現兩個類

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1.自己寫一個OpenHelper繼承SQLiteOpenHelper實現裏面的方法

實現這個類就可以不用管數據庫的創建和連接。。等等操作
實現如下：

package com.tu.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseOpenHelper extends SQLiteOpenHelper {


    public DatabaseOpenHelper(Context context) {
        super(context, "testdatabase", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        String sql = "create table person(_id integer primary key,name varchar(20),age integer);";
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

}

2.寫一個DAO類 用來對數據庫進行增刪改查等操作

實現如下：

package com.tu.dao;

import java.util.LinkedList;
import java.util.List;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import com.tu.bean.Person;
import com.tu.db.DatabaseOpenHelper;

public class PersonDao {

    private SQLiteOpenHelper mHelper = null;

    public PersonDao(Context context) {
        this.mHelper = new DatabaseOpenHelper(context);
    }

    /**
     * 插入一條Person數據
     */
    public void insert(String personNmae,int personAge){
        SQLiteDatabase db = mHelper.getWritableDatabase();
        if(db.isOpen()){
            db.execSQL("insert into person(name,age) values(?,?);", new Object[]{personNmae,personAge});
            db.close();
        }
    }

    /**
     * 根據Person名字刪除數據庫中的條目
     * @param personNmae
     */
    public void delete(String personNmae){
        SQLiteDatabase db = mHelper.getWritableDatabase();
        if(db.isOpen()){
            db.execSQL("delete from person where name = ?;", new String[]{personNmae});
            db.close();
        }
    }

    public List<Person> queryAll(){
        SQLiteDatabase db = mHelper.getReadableDatabase();
        if(db.isOpen()){
            List<Person> personList = new LinkedList<Person>();
            Person person = null;
            Cursor cursor = db.rawQuery("select name,age from person;", null);
            if(cursor != null && cursor.getCount() > 0){
                while(cursor.moveToNext()){
                    person = new Person(0, cursor.getString(0), cursor.getInt(1));
                    personList.add(person);
                }
                cursor.close();
                db.close();
                return personList;
            }
        }
        db.close();
        return null;
    }

}