Wednesday, April 27, 2011

Getting Your Big Ass Database onto Your Android Phone

Yeah, I effing did it!!!!!!!!!! (Sorry, still pumped from finally getting this to work.)

First off: giving credit where credit is due. Many many many thanks to my sources:

http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

http://www.mail-archive.com/android-developers@googlegroups.com/msg28194.html

http://www.chriskopec.com/blog/2010/mar/13/deploying-android-apps-with-large-databases/


My project requires a preformed database (SQLite), which in total comes out to a whopping 17mb. Ridiculous I know, but my boss wants it all packaged with the app, and not just to be available online. Hypothetically, getting this to work should be as easy as creating a blank db and then copying the existing one over it from assets or raw. And this totally works-- if your db is smaller than 1mb. So I went and got some free file splitting software (http://www.dekabyte.com/filesplitter/) and split my db file into 1mb pieces. I put the pieces in the raw directory.

I created the DataBaseHelper class and made the necessary tweaks:


public class DataBaseHelper extends SQLiteOpenHelper {


// The Android's default system path of your application database.
private static final String DB_PATH = "/data/data/com.instacare/databases/";


private static final String DB_NAME = "MDAtHand";


private SQLiteDatabase myDataBase;


private final Context myContext;
Resources resources;


/**
* Constructor Takes and keeps a reference of the passed context in order to
* access to the application assets and resources.

* @param context
*/
public DataBaseHelper(Context context) {


super(context, DB_NAME, null, 1);
this.myContext = context;


// super(context, DB_NAME, null, 1);
resources = context.getResources();
}


/**
* Creates a empty database on the system and rewrites it with your own
* database.
* */
public void createDataBase() throws IOException {


boolean dbExist = checkDataBase();


if (dbExist) {
// do nothing - database already exist


copyDataBase();


} else {


// By calling this method and empty database will be created into
// the default system path
// of your application so we are gonna be able to overwrite that
// database with our database.
this.getReadableDatabase();


try {


copyDataBase();


} catch (IOException e) {


throw new Error("Error copying database");


}
}


}


/**
* Check if the database already exist to avoid re-copying the file each
* time you open the application.

* @return true if it exists, false if it doesn't
*/
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 does't exist yet.


}


if (checkDB != null) {


checkDB.close();


}


return checkDB != null ? true : false;
}


/**
* Copies your database from your local assets-folder to the just created
* empty database in the system folder, from where it can be accessed and
* handled. This is done by transfering bytestream.
* */
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;


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


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


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


InputStream databaseInput = null;
// String outFileName = DB_PATH + DbConsts.DATABASE_NAME;
String outFileName = DB_PATH + DB_NAME;
OutputStream databaseOutput = new FileOutputStream(outFileName);


byte[] buffer = new byte[1024];
int length;


databaseInput = resources.openRawResource(R.raw.datafile01);
while ((length = databaseInput.read(buffer)) > 0) {
databaseOutput.write(buffer, 0, length);
databaseOutput.flush();
}
databaseInput.close();
databaseInput = resources.openRawResource(R.raw.datafile02);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile03);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();


   databaseInput = resources.openRawResource(R.raw.datafile04);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile05);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile06);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile07);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile08);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile09);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile10);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile11);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile12);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile13);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile14);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile15);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile16);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
   databaseInput = resources.openRawResource(R.raw.datafile17);
   while((length = databaseInput.read(buffer)) > 0) {
       databaseOutput.write(buffer, 0, length);
       databaseOutput.flush();
   }
   databaseInput.close();
databaseOutput.flush();
databaseOutput.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) {


}


// Add your public helper methods to access and get content from the
// database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd
// be easy
// to you to create adapters for your views.


}

Then I added this awesomeness to the main.java file


DataBaseHelper myDbHelper = new DataBaseHelper(this);
        //myDbHelper = new DataBaseHelper(this);

        try {

         myDbHelper.createDataBase();

  } catch (IOException ioe) {

  throw new Error("Unable to create database");

  }

  try {

  myDbHelper.openDataBase();

  }catch(SQLException sqle){

  throw sqle;

  }


Thats it :)

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