1.4. Hooking up the user interface

At this stage, you can determine from the CoinTossViewController class definition that the user interface should have at least two UILabel controls and that it should invoke the callHeads or callTails messages whenever the user wants to call the result of a new coin toss. You haven’t yet specified where on the screen the labels should be positioned or how the user requests that a coin toss be made.

There are two ways to specify this kind of detail. The first is to write source code that creates the user interface controls, configures their properties such as font size and color, and positions them onscreen. This code can be time consuming to write, and you can spend a lot of your time trying to visualize how things look onscreen.