Problems creating BD android

I'm following the Android Developers tutorial to create a BD: link

I use Android Studio 2.2.3 and an Alcatel Pixi 4 with Android 6.0 for testing. When you run the App you just have to create a BD with a table and insert a record, on the device the App screen appears with the typical Hello world. The problem is that I do not see the file with the BD in the ADM / DDMS In the File explorer the directory "data /" only contains a file "default.pro"

These are the classes with the code:

// MainActivity.java
package com.example.orici.dbtest;
import android.app.Activity;
import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView( R.layout.activity_main );

        FeedReaderDbHelper mDbHelper = new FeedReaderDbHelper( this );
        SQLiteDatabase db = mDbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE, "Mi título");
        values.put(FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE, "Unas pruebas");

        long newRowId = db.insert(
            FeedReaderContract.FeedEntry.TABLE_NAME, null, values
        );
    }

} //class



// FeedReaderContract.java
package com.example.orici.dbtest;
import android.provider.BaseColumns;

public final class FeedReaderContract {

    private static final String TEXT_TYPE = " TEXT";
    private static final String COMMA_SEP = ",";
    protected static final String SQL_CREATE_ENTRIES =
            "CREATE TABLE " + FeedEntry.TABLE_NAME + " (" +
                    FeedEntry._ID + " INTEGER PRIMARY KEY," +
                    FeedEntry.COLUMN_NAME_TITLE + TEXT_TYPE + COMMA_SEP +
                    FeedEntry.COLUMN_NAME_SUBTITLE + TEXT_TYPE + " )";
    protected static final String SQL_DELETE_ENTRIES =
            "DROP TABLE IF EXISTS " + FeedEntry.TABLE_NAME;

    private FeedReaderContract() {}

    // Inner class that defines the table contents
    public static class FeedEntry implements BaseColumns {
        public static final String TABLE_NAME           = "entry";
        public static final String COLUMN_NAME_TITLE    = "title";
        public static final String COLUMN_NAME_SUBTITLE = "subtitle";

    } //class
} //class



//FeedReaderDbHelper.java
package com.example.orici.dbtest;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import static com.example.orici.dbtest.FeedReaderContract.SQL_CREATE_ENTRIES;

public class FeedReaderDbHelper extends SQLiteOpenHelper {
    public static final int DATABASE_VERSION = 1;
    public static final String DATABASE_NAME = "FeedReader.db";

    public FeedReaderDbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL( FeedReaderContract.SQL_CREATE_ENTRIES );
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL( FeedReaderContract.SQL_DELETE_ENTRIES );
        onCreate(db);
    }
    @Override
    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        onUpgrade(db, oldVersion, newVersion);
    }

} //class