Where do I put recreate() after changing a theme using preferences?

Question

I have been trying to add a dark mode to my app and have mainly been using this site (Tutorial) to learn how to implement it. Everything works other than the theme does not change until I restart the app. After some research I have found that recreate() would be the correct way to fix this issue, but I do not know where to implement it.

Currently my oncreate method in the main activity looks like:

PreferenceManager.setDefaultValues(this, R.xml.settings_pref, false);
    SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
    Boolean contrastPref = sharedPref.getBoolean (Navigation.KEY_PREF_CONTRAST_SWITCH, false);
    setTheme(contrastPref? R.style.AppTheme_Dark : R.style.AppTheme);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_navigation);........

With this just below the oncreate method

public static final String
        KEY_PREF_CONTRAST_SWITCH = "contrast_switch";

The fragment that holds the preference switch looks like this:

public  class SettingsFragment extends PreferenceFragmentCompat {
@Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
    setPreferencesFromResource(R.xml.settings_pref, rootKey);
}}

Thanks for the help :)

Answer 1

If you are changing theme from SettingFragment then call getActivity().recreate() from SettingFragment.