mine is not really a programming problem but a design problem regarding the Model-View-Controller design pattern in IOS programming. I am new to IOS but I really want to do the things in the right way. So I have this view that does some animations but I want to "notify" the Controller when the animations end. I know that the View cannot have a reference to the Controller. Reading the page: <https://developer.apple.com/library/ios/#referencelibrary/GettingStarted/RoadMapiOS/chapters/StreamlineYourAppswithDesignPatterns/StreamlineYourApps/StreamlineYourApps.html>

In the first figure the view - controller communication is only **user action** (IBActions from the view) and **update** from controller. Possible solution that I have thought:

* Notification, even it does not exist in the figure it could be OK
* Controller polls the status of a property of the view until the animations finishes (might block the main thread if I'm not wrong)
* Key Value Observing, seems to be like a Notification.

Do you have any idea or best practice to exchange? Thanks in advance