private void onToggleColors() { if (K9.getK9MessageViewTheme() == K9.THEME_DARK) { K9.setK9MessageViewTheme(K9.THEME_LIGHT); } else { K9.setK9MessageViewTheme(K9.THEME_DARK); } new AsyncTask<Object, Object, Object>() { @Override protected Object doInBackground(Object... params) { Context appContext = getActivity().getApplicationContext(); Preferences prefs = Preferences.getPreferences(appContext); Editor editor = prefs.getPreferences().edit(); K9.save(editor); editor.commit(); return null; } }.execute(); mFragmentListener.restartActivity(); }