/*
******************************************************************************
* Parts of this code sample are licensed under Apache License, Version 2.0 *
* Copyright (c) 2009, Android Open Handset Alliance. All rights reserved. *
* * *
* Except as noted, this code sample is offered under a modified BSD license. *
* Copyright (C) 2010, Motorola Mobility, Inc. All rights reserved. *
* *
* For more details, see MOTODEV_Studio_for_Android_LicenseNotices.pdf *
* in your installation folder. *
******************************************************************************
*/
package me.evis.mobile.noodle;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
/**
* <p>
* This class copies a SQLite database from your application's assets directory
* to /data/data/<your_application_package>/databases/ so you can access it
* using the SQLite APIs provided by the Android SDK. Note that
* {@link NoodlesDbHelper#copyDatabaseFile()} checks for the existence of
* the database and only copies it if needed.
* </p>
* <p>
* {@link NoodlesDbHelper#copyDatabaseFile()} calls
* {@link SQLiteOpenHelper#getReadableDatabase()}, which in turn calls
* {@link SQLiteOpenHelper#onCreate(SQLiteDatabase)}. Be aware that the
* implementation of the overridden
* {@link SQLiteOpenHelper#onCreate(SQLiteDatabase)} must remain empty in order
* for the copy operation to work correctly.
* </p>
* <p>
* This class includes a constructor
* {@link NoodlesDbHelper#NoodlesMetaDbHelper(Context, boolean)} which
* allows you to control whether the database file should be copied when the
* class is instantiated.
* </p>
*
* @see SQLiteOpenHelper
*/
public class NoodlesDbHelper extends SQLiteOpenHelper {
// Android's default system path for your application's database.
private static String DB_PATH = "/data/data/me.evis.mobile.noodle/databases/";
private static String DB_NAME = "noodles.db";
private final Context myContext;
/**
* Constructor Keeps a reference to the passed context in order to access
* the application's assets.
*
* @param context
* Context to be used
*/
public NoodlesDbHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/**
* This constructor copies the database file if the copyDatabase argument is
* <code>true</code>. It keeps a reference to the passed context in order to
* access the application's assets.
*
* @param context
* Context to be used
* @param copyDatabase
* If <code>true</code>, the database file is copied (if it does
* not already exist)
*/
public NoodlesDbHelper(Context context, boolean copyDatabase) {
// call overloaded constructor
this(context);
// copy database file in case desired
if (copyDatabase) {
copyDatabaseFile();
}
}
/*
* (non-Javadoc)
*
* @see
* android.database.sqlite.SQLiteOpenHelper#onCreate(android.database.sqlite
* .SQLiteDatabase)
*/
@Override
public void onCreate(SQLiteDatabase db) {
// Leave this method empty
}
/*
* (non-Javadoc)
*
* @see
* android.database.sqlite.SQLiteOpenHelper#onUpgrade(android.database.sqlite
* .SQLiteDatabase, int, int)
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// fill in your code here
}
/**
* <p>
* Copy the database file from the assets directory to the proper location
* where the application can access it. The database location and name is
* given by the constants {@link #DB_PATH} and {@link #DB_NAME}
* respectively.
* </p>
* <p>
* If the database file already exists, it will not be overwritten.
* </p>
*/
public void copyDatabaseFile() {
// variables
InputStream myInput = null;
OutputStream myOutput = null;
SQLiteDatabase database = null;
// only proceed in case the database does not exist
if (!checkDataBaseExistence()) {
// get the database
database = this.getReadableDatabase();
try {
// Open your local db as the input stream
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
myOutput = new FileOutputStream(outFileName);
// transfer bytes from the input file to the output file
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
} catch (FileNotFoundException e) {
// handle your exception here
} catch (IOException e) {
// handle your exception here
} finally {
try {
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
// close the database in case it is opened
if (database != null && database.isOpen()) {
database.close();
}
} catch (Exception e) {
// handle your exception here
}
}
}
}
/**
* Returns whether the database already exists.
*
* @return <code>true</code> if the database exists, <code>false</code>
* otherwise.
*/
private boolean checkDataBaseExistence() {
// database to be verified
SQLiteDatabase dbToBeVerified = null;
try {
// get database path
String dbPath = DB_PATH + DB_NAME;
// try to open the database
dbToBeVerified = SQLiteDatabase.openDatabase(dbPath, null,
SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
// do nothing since the database does not exist
}
// in case it exists, close it
if (dbToBeVerified != null) {
// close DB
dbToBeVerified.close();
}
// in case there is a DB entity, the DB exists
return dbToBeVerified != null ? true : false;
}
}
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