温故知新----5种数据存储方式之SQLiteOpenHelper

温故知新----5种数据存储方式之SQLiteOpenHelper,第1张

概述SQLiteOpenHelper常用方法: DBHelper.Java <span style="font-family:Microsoft YaHei;font-size:18px;">import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sql

sqliteOpenHelper常用方法:



DBHelper.Java

<span >import androID.content.Context;import androID.database.sqlite.sqliteDatabase;import androID.database.sqlite.sqliteOpenHelper;/** * Created by tangjiarao on 16/9/7. */public class DbHelper extends sqliteOpenHelper{    private static final String DATABASE_name = "person.db"; //数据库名称    private static final int DATABASE_VERSION = 1;//数据库版本    public DbHelper(Context context){        super(context,DATABASE_name,null,DATABASE_VERSION);    }        public voID onCreate(sqliteDatabase db) {        db.execsql("CREATE table person " +                "(_ID integer primary key autoincrement," +                "name varchar(20)," +                "age varchar(10))");    }    @OverrIDe    public voID onUpgrade(sqliteDatabase db,int i,int i1) {        db.execsql("DROP table IF EXISTS person");        onCreate(db);    }}</span>
PersonService.Java
<span >import androID.content.Context;import androID.database.Cursor;import androID.database.sqlite.sqliteDatabase;import java.util.ArrayList;import java.util.List;import tplusr.storagetest.db.DbHelper;public class PersonService {    private DbHelper dbHelper;    private sqliteDatabase db;    public PersonService(Context context) {        dbHelper=new DbHelper(context);        db=dbHelper.getReadableDatabase();    }    /**     * 插入方法     * @param person     */    public voID insert(Person person){        sqliteDatabase db=dbHelper.getWritableDatabase();        db.execsql("insert into person(name,age) values(?,?)",new Object[]{person.getname(),person.getAge()});    }    /**     * 删除方法     * @param _ID     */    public voID delete(Integer _ID){        sqliteDatabase db=dbHelper.getWritableDatabase();        db.execsql("delete from person where _ID=?",new Object[]{_ID});    }    /**     * 查找某行数据方法     * @param _ID     * @return     */    public Person find(Integer _ID){        sqliteDatabase db=dbHelper.getWritableDatabase();        Cursor cursor=db.rawquery("select * from person where _ID=?",new String[]{_ID.toString()});        if(cursor.movetoFirst()){            int ID = cursor.getInt(cursor.getColumnIndex("_ID"));            String name = cursor.getString(cursor.getColumnIndex("name"));            String age = cursor.getString(cursor.getColumnIndex("age"));            Person person = new Person();            person.set_ID(ID);            person.setname(name);            person.setAge(age);            return person;        }        return null;    }    /**     * 查找所有数据方法     * @return     */    public List<Person> findAll(){        sqliteDatabase db=dbHelper.getReadableDatabase();        List<Person> persons = new ArrayList<Person>();        Cursor cursor=db.rawquery("select * from person",null);        while(cursor.movetoNext()){            Person person=new Person();            int ID=cursor.getInt(cursor.getColumnIndex("_ID"));            String name=cursor.getString(cursor.getColumnIndex("name"));            String age=cursor.getString(cursor.getColumnIndex("age"));            person.set_ID(ID);            person.setname(name);            person.setAge(age);            persons.add(person);        }        return persons;    }}</span>
Person.Java
<span >public class Person {    private int _ID;    private String name;    private String age;    public int get_ID() {        return _ID;    }    public voID set_ID(int _ID) {        this._ID = _ID;    }    public String getname() {        return name;    }    public voID setname(String name) {        this.name = name;    }    public String getAge() {        return age;    }    public voID setAge(String age) {        this.age = age;    }}</span>
DBActivity.Java
<span >import androID.support.v7.app.AppCompatActivity;import androID.os.Bundle;import androID.util.Log;import java.util.List;import tplusr.storagetest.R;public class DBActivity extends AppCompatActivity {    @OverrIDe    protected voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_db);        PersonService service =new PersonService(this);        Person person =new Person();        person.setname("ahdad");        person.setAge("39");        service.insert(person);        List<Person> p =service.findAll();        for (int i =0;i<p.size();i++){            Log.d("db",p.get(i).toString());        }    }}</span>
结果:
总结

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