andorid SQLite數據庫創建文件

package com.hanqi.application3;

import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Toast;

public class DataActivity2 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_data2);
    }
    //繼承SQLiteOpenHelper
    class DBHelper extends SQLiteOpenHelper
    {
        //構造方法
        //name 數據庫名
        //version數據庫版本號
        public DBHelper(String name,  int version) {
            //寫在第一行
            super(DataActivity2.this, name, null, version);
        }
        //回調方法
        //在創建數據庫時調用
        //什麼時候創建數據庫：連接數據庫的時候,如果數據文件不存在
        //只調用一次
        @Override
        public void onCreate(SQLiteDatabase db) {

            //1.創建數據庫的語句
            String creatTable = "create table user1 (_id integer PRIMARY KEY AUTOINCREMENT NOT NULL,name varchar,age int)";
            db.execSQL(creatTable);

            //2.初始化數據
            ContentValues cv= new ContentValues();
            cv.put("name","tom");
            cv.put("age", 30);
            //如果不成功返回-1
            long l = db.insert("user1",null,cv);

            Toast.makeText(DataActivity2.this, "id="+l, Toast.LENGTH_SHORT).show();

        }
        //升級數據庫
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        }
    }
    //創建數據庫
    public void bt_bt1onClick(View v)
    {
        //創建
        DBHelper dh = new DBHelper("test.db",1);
        //獲取數據庫實例
        SQLiteDatabase sdd = dh.getWritableDatabase();



    }
}