PreferenceCategory account = (PreferenceCategory) getPreferenceScreen().findPreference(getString(R.string.pref_sipaccount_key));
EditTextPreference username = (EditTextPreference) account.getPreference(0);
username.setText(mPrefs.getAccountUsername(n));
username.getEditText().setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_EMAIL_ADDRESS);
username.setOnPreferenceChangeListener(usernameChangedListener);
username.setSummary(username.getText());