Inter-View communication.

I am writing an iPad app which has two views (Left and Right)
When something in the one view I want the other view to know.

LeftView.RightValueChanged
RightView.LeftValueChanged

In a model view controller application, shouldn’t the controller be the one to receive the value changed event from the view and pass it on to the other view

When you create and iOS app one gets an App class, is that where the events should go and be handled?

If you want to use the notifier pattern I have classes using native Xojo present in iOSKit. Look at the Notification_Center module. You can setup one view as an observer and have the other generate notifications. Super easy to use

You can possibly talk directly using public methods.

Cast the contents of master or detail to your view class, and call a method of it:

MyTypeOfView(self.ParentSplitView.detail).MyMethod("A Value")