getTheme method
Retrieves the current theme from SharedPreferences as a boolean value.
The retrieved value is true
if the app is currently using the dark
theme, and false
otherwise.
If the theme is not set, the default value is false
(i.e. the light theme).
Implementation
Future<bool> getTheme() async {
final sharedPreferences = await SharedPreferences.getInstance();
return sharedPreferences.getBool(themeKey) ?? false;
}