SettingFragment.kt

    private val modeChangeListener =
        Preference.OnPreferenceChangeListener { preference, newValue ->
            Log.i("newValue", newValue.toString())
            newValue as? String
            when (newValue) {
                getString(R.string.pf_light_on) -> {
                    updateTheme(AppCompatDelegate.MODE_NIGHT_YES)
                }
                getString(R.string.pf_light_off) -> {
                    updateTheme(AppCompatDelegate.MODE_NIGHT_NO)
                }
                else -> {
                    if (BuildCompat.isAtLeastQ()) {
                        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
                    } else {
                        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_AUTO_BATTERY);
                    }
                }
            }
            true
        }