Android: File not showing up on file system while trying to copy SQL file from assets to app data directory

Question

I am trying to ship an SQL file with my Android application and have the app use it. I have the file in the assets folder and I check for it and copy it if necessary when the app is created. I followed this blog post: http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

The sql file is in the assets directory when it is installed and it does perform write operations that seem correct, but the file doesn't appear anywhere on the filesystem.

Here's the code for my database helper:

package com.example.myapp;

import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

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

public class DataBaseHelper extends SQLiteOpenHelper {
private static String DB_PATH;
private static String DB_NAME = "myapp.sql";
private SQLiteDatabase myDataBase;
private final Context myContext;

public DataBaseHelper(Context context){
    super(context, DB_NAME, null, 1);
    this.myContext = context;
    DB_PATH = myContext.getFilesDir().getPath();
}

public void createDatabase() throws IOException {
    boolean dbExist = checkDataBase();
    if (dbExist) {
        // do nothing, db exists
    } else {
        this.getReadableDatabase();

        try {
            copyDataBase();
        } catch (IOException e) {
            throw new Error("Error copying database");
        }
    }
}

private boolean checkDataBase() {
    SQLiteDatabase checkDB = null;

    try {
        String myPath = DB_PATH + "/" + DB_NAME;
        checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
    } catch (SQLiteException e) {
        // database doesn't exist yet
    }

    if (checkDB != null) {
        checkDB.close();
    }

    if (checkDB != null) {
        Log.e("myapp", "Database exists");
    }

    return checkDB != null ? true : false;
}

private void copyDataBase() throws IOException {

    //Open your local db as the input stream
    InputStream myInput = myContext.getAssets().open(DB_NAME);

    // Path to the just created empty db
    String outFileName = DB_PATH + "/" + DB_NAME;
    Log.e("myapp", outFileName);

    //Open the empty db as the output stream
    OutputStream myOutput = new FileOutputStream(outFileName);
    BufferedOutputStream os = new BufferedOutputStream(myOutput);

    //transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer))>0){
        Log.e("myapp", "writing buffer");
        os.write(buffer, 0, length);
    }

    //Close the streams
    myOutput.flush();
    myOutput.close();
    myInput.close();

}

public void openDataBase() throws SQLException{

    //Open the database
    String myPath = DB_PATH + "/" + DB_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

}

@Override
public synchronized void close() {

        if(myDataBase != null)
            myDataBase.close();

        super.close();

}

@Override
public void onCreate(SQLiteDatabase db) {

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}
}

And for my main activity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    DataBaseHelper dbHelper = new DataBaseHelper(this);

    try {
        dbHelper.createDatabase();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        //e.printStackTrace();
        Log.e("myapp", "ERROR in creating database");
    }

    try {
        dbHelper.openDataBase();
    } catch (SQLException sqle) {
        Log.e("myapp", "ERROR in opening database");
        throw sqle;
    }

    SQLiteDatabase db = dbHelper.getReadableDatabase();

    String sortOrder =
            MyApp.COLUMN_NAME_NAME + " DESC";

    Cursor c = db.rawQuery("SELECT name FROM sqlite_master WHERE type='table'", null);
    if (c.moveToFirst()) {
        while (!c.isAfterLast()) {
            Log.e("myapp", c.getString(c.getColumnIndex("name")));
            c.moveToNext();
        }
    }
}

Answer 1

I had to override the getReadableDatabase function for the helper class because it has no idea to return myDatabase. The helper loads it up properly and everything, but it never actually returns it.

@Override
public SQLiteDatabase getReadableDatabase(){
    return myDataBase;
}