应该使用 WidgetsFlutterBinding.ensureInitialized(); 两次？

Question

I have used firebase and shared_preferences in the main function so I should use the instruction WidgetsFlutterBinding.ensureInitialized(); two times or one enough?

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  WidgetsFlutterBinding.ensureInitialized();
  SharedPreferences prefs = await SharedPreferences.getInstance();
 .....
  runApp( MyApp());
}

Answer 1

One time initialization is enough.

If you look at ensureInitialized() 's source code,
all it does is to check whether the WidgetsBinding instance is null or not.
If it's null , a new instance is created.

Here's the function:

    static WidgetsBinding ensureInitialized() {
      if (WidgetsBinding.instance == null)
        WidgetsFlutterBinding();
      return WidgetsBinding.instance!;
    }