flutter_appfx/lib/theme/appTheme.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_riverpod/legacy.dart';

class AppTheme {
  static final appThemeProvider = StateProvider<ThemeMode?>((ref) {
    return ThemeMode.system;
  });

  static late WidgetRef? _appWidgetRef;
  static StateController<ThemeMode?>? _appThemeNotifier;
  static setRootWidgetRef(WidgetRef ref) {
    _appWidgetRef = ref;
    _appThemeNotifier = ref.watch(appThemeProvider.notifier);
  }

  static ThemeMode? getTheme([WidgetRef? ref]) {
    if (ref != null) {
      return ref.watch(appThemeProvider);
    } else {
      return _appWidgetRef!.watch(appThemeProvider);
    }
  }

  static setTheme(ThemeMode mode) {
    _appThemeNotifier?.state = mode;
  }
}