Flutter: Shared Preferences null on Startup : <p>Problem: Shared preference bool value is <code>null</code> on startup even though I have given it a value if <code>prefs.getBool('myBool')</code> returns <code>null</code> (though my shared preferences value should already be set and saved).  It does, however, work by the time I press a button (I assume because it has finished running the async code).</p>

<p>Question: How can I force shared preferences to load on startup (so my value is not <code>null</code>) without having to press the print button?</p>

<p>Example Code:</p>

<pre><code>import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:shared_preferences/shared_preferences.dart';

void main() =&gt; runApp(new MyApp());

class MyApp extends StatefulWidget {
  MyApp({Key key}) : super(key: key);

  @override
  createState() =&gt; new MyAppState();
}

class MyAppState extends State&lt;MyApp&gt; {
  final padding = const EdgeInsets.all(50.0);

  @override
  void initState() {
    super.initState();

    MySharedPreferences.load();
    MySharedPreferences.printMyBool();
  }

  @override
    Widget build(BuildContext context) {
      return new MaterialApp(
        home: new Scaffold(
          body: new Padding(
            padding: padding,
            child: new Column(
              children: &lt;Widget&gt;[
                new Padding(
                  padding: padding,
                  child: new RaisedButton(
                    child: new Text('Save True'),
                    onPressed: () =&gt; MySharedPreferences.save(myBool: true),
                  ),
                ),
                new Padding(
                  padding: padding,
                  child: new RaisedButton(
                    child: new Text('Save False'),
                    onPressed: () =&gt; MySharedPreferences.save(myBool: false),
                  ),
                ),
                new Padding(
                  padding: padding,
                  child: new RaisedButton(
                    child: new Text('Print myBool'),
                    onPressed: () =&gt; MySharedPreferences.printMyBool(),
                ),
              ),
            ],
          ),
        ), 
      ),
    );
  }
}

class MySharedPreferences {
  static bool _myBool;

  static void load() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    _myBool = prefs.getBool('myBool') ?? false;
  }

  static void save({myBool: bool}) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    _myBool = myBool;
    await prefs.setBool('myBool', _myBool);
  }

  static void printMyBool() {
    print('myBool: ${_myBool.toString()}');
  }
}
</code></pre>

<p>Results:
  On startup, <code>myBool: null</code> is printed.  Once the button is pressed, <code>myBool: false/true</code> is then printed.</p>
