title: UIPickerView selects entity from managedObjectContext
body: <p>I'm struggling with a CoreData related problem for a while now:</p>
  
  <p>I have a View-based application with a tabbar in it.
  The first two tabs are view controllers that display content from my CoreData, the third tab has a UIPickerView, where I can select data.
  The third and the second view controllers then should select the right entity based on the UIPickerView selection.</p>
  
  <p>To clarify this a little bit more: in my managedobjectcontext I have 16 entities. Based on the UIPickerView selection in ThirdViewController I want to use the corresponding entity and update the FirstViewController and SecondViewController.</p>
  
  <p>This should also be a persistent solution, so that the user can quit the application, but the selection from UIPickerView should be stored. Maybe this is something for NSUserDefaults?</p>
  
  <p>Any help would be greatly appreciated!</p>