I have one sqlite database stored in an "assets" folder and I'd like to store it into /data/data folder within the Android device. It's just a readonly db from which I want to retrieve data.
I've been reading a lot of topics talking about that but when I check the /data/data/ folder in my device, my package isn't there. Here's the code I've been using:
public class DatabaseManager extends SQLiteOpenHelper {
private static final String TAG = "DataBaseManager";
private static String DB_PATH = "/data/data/com.my_package/databases/";
private static String DB_NAME = "my_database";
public SQLiteDatabase myDataBase;
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
* @param context
*/
public DatabaseManager(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
try {
createDataBase();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 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
Log.d("DATABASE", "ALREADY EXIST");
}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.getWritableDatabase();
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){
Log.d("DATABASE", "DOESNT EXIST");
}
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[2048];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
Log.d("COPY DATABASE", "DATABASE COPIED");
}
public void openDataBase() throws SQLException {
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
Cursor cursor = myDataBase.rawQuery("SELECT * FROM chapters", null);
while (cursor.moveToNext()) {
cursor.getString(3);
Log.d("CONTENT", cursor.getString(3));
}
myDataBase.beginTransaction();
}
@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) {
}
Thanks to the Log.d() messages, I can see the following message : "database already exists" (message from createDatabase method) and yet, I have no data in the /data/data folder of my Android device.
This seems strange to me because in checkDatabase method, I check if a database exists in myPath variable, variable whose value corresponds to DB_PATH and DB_NAME, namely the /data/data folder and, like I said, I opened the internal memory of my device and checked if something was created in the /data/data folder but nothing.
