final String user=PreferenceManager.getDefaultSharedPreferences(context).getString("username", null);
final String password=PreferenceManager.getDefaultSharedPreferences(context).getString("password", null);
if(user == null || password == null)
final String user=PreferenceManager.getDefaultSharedPreferences(context).getString("username", null);
final String password=PreferenceManager.getDefaultSharedPreferences(context).getString("password", null);
if(user == null || password == null)