Adding some animation magic

We all know, as developers, the pain of finding that an idea that we had thought simple and quick to implement turns out to be much harder than we had imagined. But when programming with WatchKit, you will often find that some quite advanced-sounding technologies are, in fact, extremely easy to use.

WKInterfaceController animation methods are just that, and so we can add some flair to our app by changing the color of the button border – which is to say, the BorderGroup background color - using a call to animateWithDuration.

First, let's add some code to our InterfaceController class, and then we will take a look at what we have done.

1. Control-drag from the Group in the Document Outline to the code in the assistant editor, to create an Outlet connection:
   
2. Enter the name borderGroup as shown, and hit Connect.
   

   Xcode creates a new IBOutlet (connection) between the interface and the source code:

   @IBOutlet var borderGroup: WKInterfaceGroup!

3. Next, below the HelloButtonTapped...