title: Do I need to use ProxyProvider - or restructure my data model?
body: <p>This is my first flutter app - it's an Expenses splitter.  Passing around callbacks was getting very complex, so I switched to Provider - but was getting errors which I think are because of my data model having dependencies (see snippet below).  Note: I've assumed that change notifiers on the dependent classes is a better approach than just having one change-notifier for any change. </p>
  
  <p>So I'm now switching to a ProxyProvider setup.  Which is all feeling a bit too complex for what I thought would be quite a simple app.</p>
  
  <p>Question: is there a simpler way to set-up the data model so I can use a simple provider pattern - or is ProxyProvder and the model (as it already is) the best approach? </p>
  
  <pre><code>class DBModel with ChangeNotifier {
    List&lt;TripModel&gt; _trips; // all the trips
    List&lt;PersonModel&gt; _addressBook; // Addressbook of people
  
  ...etc
  
  
  class TripModel with ChangeNotifier {
  
     final String id;
     String destination;
     DateTime startDate;
     DateTime endDate;
     List&lt;String&gt; memberIDs;
     List&lt;ExpenseModel&gt; _expenses;
  
    TripModel ({this.id, this.destination, this.startDate, this.endDate, this.memberIDs, this.expenses});
  
  
    List&lt;ExpenseModel&gt; get expenses {
      return [..._expenses];
    }
  </code></pre>