How to apply a theme / style in android without restarting the activity?

I have an application where the user can chose between several different colored themes from a PreferenceActivity and thereby change the theme / color of the entire application. But the changes selected in the PreferenceActivity do not apply immediately. The changes are applied only when the user reenters the PreferenceActivity.

I know I can call recreate() every time a theme is chosen, but I want to know if a better solution exists without recreating the entire activity.

Here is an video of how it currently works: https://www.youtube.com/watch?v=oU8xIUi_48A

This is where I set the chosen value from the preferenceList in my PreferenceActivity:

@Override
public void onCreate(Bundle savedInstanceState) {
    setTheme();
    themecolorList.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            switch (themecolorList.getValue()) {

                case "grey":
                    themecolorList.getEditor().putString("grey", "green").apply();
                    break;
                case "green":
                    themecolorList.getEditor().putString("green", "green").apply();
                    setTheme(R.style.AppTheme_default);
                    break;
                case "blue":
                    themecolorList.getEditor().putString("blue", "green").apply();
                    break;
                case "yellow":
                    themecolorList.getEditor().putString("yellow", "green").apply();
                    break;
                case "red":
                    themecolorList.getEditor().putString("red", "green").apply();
                    break;
                case "pink":
                    themecolorList.getEditor().putString("pink", "green").apply();
                    break;

                default:
                    themecolorList.getEditor().putString("green", "green").apply();
                    break;
            }

            recreate();
            return true;


        }
    });
  }

The method setTheme(); is called in my PreferenceActivitys onCreate(); method

private void setTheme() {

   SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
    switch (sharedPreferences.getString("THEME_KEY", "green")) {

        case "grey":
            setTheme(R.style.AppTheme_Grey);
            break;

        case "green":
            setTheme(R.style.AppTheme_default);
            break;

        case "blue":
            setTheme(R.style.AppTheme_Blue);
            break;

        case "yellow":
            setTheme(R.style.AppTheme_Yellow);
            break;

        case "red":
            setTheme(R.style.AppTheme_Red);
            break;

        case "pink":
            setTheme(R.style.AppTheme_Pink);
            break;

        default:
            getApplication().setTheme(R.style.AppTheme_default);
            setTheme(R.style.AppTheme_default);
            break;
    }
}