Flutter语言 - 如何使用共享偏好和SwitchTile保存memode偏好

Question

我的目标是保存ThemeMode首选项，即使在应用程序关闭时。我试着遵循一些指南，但没有成功，我需要知道我做错了什么。

有人能帮我，给我提供正确的代码吗?

provider.dart

class ThemeProvider extends ChangeNotifier {
  ThemeMode themeMode = ThemeMode.light;
  bool get isDarkMode => themeMode == ThemeMode.dark;
  void toggleTheme(bool isOn) {
    themeMode = isOn ? ThemeMode.dark : ThemeMode.light;
    notifyListeners();
  }
}

drawer.dart

@override
  Widget build(BuildContext context) {
    final themeProvider = Provider.of<ThemeProvider>(context);
    return Drawer(
      child: ListView(
        physics: const ScrollPhysics(),
        padding: EdgeInsets.zero,
        children: <Widget>[
          SwitchListTile(
            secondary: Icon(
              themeProvider.isDarkMode ? Icons.dark_mode : Icons.light_mode,
            ),
            title: const Text('Tema'),
            value: themeProvider.isDarkMode,
            onChanged: (value) {
              final provider =
                  Provider.of<ThemeProvider>(context, listen: false);
              provider.toggleTheme(value);
            },
          ),
        ],
      ),
    );
  }

Answer 1

这就是我为我的应用程序使用的，它有三个主题，但工作…

  ThemeNotifier(IAppRepository appRepository) {
    _appPrefsUseCase = AppPrefsUseCase(appRepository);
    _loadFromPrefs();
  }
  toggleTheme(int index) {
    var type = ThemeType.values[index];
    _saveToPrefs(type);
    notifyListeners();
  }
  void _loadFromPrefs() async {
    final _theme = _appPrefsUseCase?.call<String>(AppKeys.theme);
    _userTheme = ThemeType.values
        .firstWhere((t) => t.toString() == _theme, orElse: () => _userTheme);
    notifyListeners();
  }
  void _saveToPrefs(ThemeType type) {
    _userTheme = type;
    _appPrefsUseCase?.savePref(key: AppKeys.theme, value: type.toString());
  }
}