006_02SQLite_OpenHelper

package com.example.sqliteopenhelper;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class MydbOpenHelper extends SQLiteOpenHelper{
    
    public MydbOpenHelper(Context context, String name, CursorFactory factory, int version){
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createtable = "create table user(id int, name varchar(20), password char(8))";
        db.execSQL(createtable);
        System.out.println("MydbOpenHelper.onCreate()");
        
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i("MydbOpenHelper","oldVersion" + oldVersion + "newVersion" + newVersion);
        System.out.println("MydbOpenHelper.onUpgrade()");
        
    }
}

package com.example.sqliteopenhelper;

import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

public class MainActivity extends Activity {
    SQLiteDatabase db = null;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        MydbOpenHelper dbhelper = new MydbOpenHelper(this, "userinfo.db", null, 1);
        db = dbhelper.getWritableDatabase();

    }
    
    public void insert(View v){
        ContentValues c = new ContentValues();
        //c.put("id", 2);
        //c.put("name", "user222");
        //c.put("password", "222");
        
        c.put("id", 1);
        c.put("name", "user1");
        c.put("password", "222");
        
        db.insert("user", null, c);
    }
    public void delete(View v){
        db.delete("user", "id=? and name=?", new String[]{"1","user1"});
    }
    public void update(View v){
        ContentValues c = new ContentValues();
        c.put("name", "user222");
        c.put("password", "88888888");
        db.update("user", c, "id=?", new String[]{"2"});
    }
    public void query(View v){
        String[] colums = {"id", "name", "password"};
        Cursor c = db.query("user", colums, null, null, null, null, null);
        
        while(c.moveToNext()){
            int id = c.getInt(c.getColumnIndex("id"));
            String username = c.getString(c.getColumnIndex("name"));
            String password = c.getString(c.getColumnIndex("password"));
            Log.i("sqliteopenhelper", id + "," +username+"," +password);
        }
    }
}