storing android application data on SD Card

It's better practice to use Environment.getExternalStorageDirectory() than to hard code "/sdcard"It's not always certain that the folder name will be called that. Also, the Environment class offers a getExternalStorageState() method to check on if the external storage is even available.

To begin:

Depending on the model/os, you can access the sd card root directory with:

File externalStorage = Environment.getExternalStorageDirectory();

This will refer to the internal sd storage or internal sd memory.

externalStorage.getAbsolutePath() 

will return one of the following values

"/sdcard/" or "/mnt/sdcard/"

To access the external sd memory or micro SD, that you usually plug from the outside of the phone/tablet, you must use one of the following folders that android creates to point to the external memory:

"/mnt/sdcard/sd" "/mnt/sdcard/external_sd""/sdcard/external_sd""/sdcard/sd" "/mnt/sdcard/"

ps: you can notice an empty folder external_sd or sd on the internal sdcard

memory, this folder is empty and its used to point to external micro sd card.

at the end make sure that you have read/write access to the sd card android.permission.WRITE_EXTERNAL_STORAGE in the android manifest xml.

finally you must specify the file name and your ready

private SQLiteDatabase DB = null;private static final String DATABASE_NAME = "MyDb.db"; ////////////File sdcard = Environment.getExternalStorageDirectory();String dbfile = sdcard.getAbsolutePath() + File.separator+ "external_sd" + File.separator + DATABASE_NAME;DB = SQLiteDatabase.openDatabase(dbfile, null,SQLiteDatabase.NO_LOCALIZED_COLLATORS);///////////

and your ready to go ...

Here is another neat little trick.The Application has a number of methods which are called to acquire paths.In particular the application has the method getDatabasePath with is used by SQLiteOpenHelper to construct the path.A custom application class can override these methods to provide different paths including paths in the getExternalStorageDirectory.

The external storage is either application specific or public.There are methods, replacing the getExternalStorageDirectory mechanism,getExternalFilesDir() and getExternalStoragePublicDirectory() respectively.