Flutter shared_preferences getString() not returning a String?

Question

I am quite new to Flutter, and I am now trying to use its shared_preferences package for saving a String and retrieving it back.

Now, I believe getString should return a String (at least that's what VS Code tells me), so I declared a wrapper function that returns a String:

String getName() async {
  final prefs = await SharedPreferences.getInstance();
  return prefs.getString('name');
}

However, this does not compile, with the error (notice the missing quotation mark of 'String):

A value of type 'String can't be returned from method 'getName' because it has a return type of 'String'

If I remove the return type altogether, the error goes away:

getName() async {
  final prefs = await SharedPreferences.getInstance();
  return prefs.getString('name');
}

Can anyone explain what is going on here? What does getString actually return?

Dheeraj Avvari · Accepted Answer · 2020-01-07 19:44:56Z

4

You have to return a Future as yours is an async function

Future<String> getName() async {
  final prefs = await SharedPreferences.getInstance();
  return prefs.getString('name');
}

answered Jan 7, 2020 at 19:44

Dheeraj Avvari

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Comments

Anis R. · Accepted Answer · 2020-01-07 19:59:20Z

0

Okay, I now figured out what I was missing: my function is async!

And as it turns out, async function in Dart have a return type of Future.

answered Jan 7, 2020 at 17:58

Anis R.

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