public class TestDB extends SQLiteOpenHelper {

    private static final String DATABASE_NAME = "usertest.db";

    private static final int DATABASE_VERSION = 1;

    public TestDB (Context context){

        super(context, context.getExternalFilesDir(null).getAbsolutePath() + "/" +  DATABASE_NAME, null, DATABASE_VERSION );

    }

    ...

}

http://*.com/questions/4806181/sqlite-database-on-sd-card