Can't Initialize Async SharedPreferences Class via Constructor

[Matthew Jones]

I'm attempting to use this package:

https://pub.dartlang.org/packages/shared_preferences

Here's my code:

import 'package:shared_preferences/shared_preferences.dart';


class SharedPreferencesProvider {
  SharedPreferences prefs;


  SharedPreferencesProvider() {
    init();
  }


  // Get get instance of SharedPreferences upon instantiation.
  void init() async {
    prefs = await SharedPreferences.getInstance();
  }


  // Save some data
  void saveData() {
      prefs.setString('key', 'value');
  }
}

When I run this, I get an error stating that setString was called on null. I did some investigating, and it appears that the prefs property is never actually initiated. It really is null when called by saveData(). 

I'm guessing this has to do with async operations in Dart and the way constructors work, but I'm not sure how to get around it. How can I initialize my prefs property so I can utilize it across my class?

[Matthew Jones]

Nevermind... This fixed my issue:

https://stackoverflow.com/questions/38933801/calling-an-async-method-from-component-constructor-in-dart

[Steven McDowall]

You need to await the init() call since it’s also asynchronous 

--
You received this message because you are subscribed to the Google Groups "Flutter Dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to flutter-dev...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.