Changes

iPhone user interfaces are constructed using a hierarchical approach whereby different views are related through a parent/child relationship. At the top of this hierarchy sits the UIWindow object. Other views are then added to the hierarchy. If we take the example from the chapter entitled [[Creating an Interactive iPhone App]], we have a design that consists of a window, a view, a text field, a button and a label. The view hierarchy for this user interface would be drawn as illustrated in the following figure:

[[Image:iphone_view_hierarchy.jpg|An example of an iPhone user interface view hierarchy]]