title: ChangeNotifier not listening to value change
body: <p>I want to notify the wrapper when a value changes from null to a number, but the wrapper seems not to receive the change. Check my code below:</p>
  <pre><code>class setID with ChangeNotifier{
  String studyID;
  
  void setStudyID(String study){
    studyID = study;
    notifyListeners();
    }
  }
  </code></pre>
  <p>in main.dart,</p>
  <pre><code>return MultiProvider(
    providers: [
      ChangeNotifierProvider(create: (_) =&gt; setID()),
      // others providers here
      ],
    child: MaterialApp(
        home: Wrapper(),
      ),
  </code></pre>
  <p>in wrapper.dart,</p>
  <pre><code>final studyID = Provider.of&lt;setID&gt;(context).studyID;
  </code></pre>
  <p>When the value is changed in setID class, no value is received in the wrapper. Could anyone help me out? Thank you in advance.</p>