title: Computed (NSObject) Properties in SwiftUI don't update the view
body: <p>So, I want to have a <code>Text</code> that changes its content based on the contents of my CoreData Model. To do that I used a computed property in Xcode beta 4 but it doesn't seem to work anymore. Either that's a bug or there is some other issue I don't see?</p>
  
  <p>The problem I have exactly is that my View (and the computed property) don't seem to get updated when <code>self.objectWillChange.send()</code> is called in my store.</p>
  
  <p>I also tried to 'export' my var into the store and get it from there, with the same result...</p>
  
  <hr>
  
  <p><strong>EDIT:</strong>
  I just tried the same with another class and it didn't work with just <code>objectWillChange.send()</code> but only with <code>@Published</code> however, even that stopped working if the class inherited from NSObject...</p>
  
  <hr>
  
  <p>I just found out: with </p>
  
  <pre class="lang-swift prettyprint-override"><code>struct Today: View {
      @EnvironmentObject var myStore: DateStore
      var hasPlans: Bool {
          guard let plans = myStore.getPlans() else { return false }
          return plans.isEmpty
      }
  
      var body: some View{
          VStack{
              Text(hasPlans ? "I have plans":"I have time today")
              Button(action: {
                  self.myStore.addPlans(for: Date())
              }) {
                  Text("I have plans")
              }
      }
  }
  
  class DateStore: NSObject, ObservableObject, NSFetchedResultsControllerDelegate {
      private var fetchedResultsController: NSFetchedResultsController&lt;DateStore&gt;
      //...
      public func addPlans(for date: Date){
          //{...}
          if let day = self.dates.first(where: { $0.date == date}){
              day.plans += 1
              saveChanges()
          }else{
              self.create(date: dayDate)
          }
      }
  
      func controllerDidChangeContent(_ controller: NSFetchedResultsController&lt;NSFetchRequestResult&gt;) {
          self.objectWillChange.send()
      }
  }
  
  
  </code></pre>
  
  <p>That's a very simplified version of my problem and I know that my DataModel works because the values change and <code>self.objectWillChange.send()</code> is called, but my View isn't updated for some reason....</p>