The Core iOS Developer’s Cookbook, Fifth Edition

Using Tags to Find Views

Tags let you avoid passing user interface elements around your program by making them directly accessible from any parent view. The viewWithTag: method recovers a tagged view from a child hierarchy. The search is recursive, so the tagged item need not be an immediate child of the view in question. You can search from the window with [window viewWithTag:101] and find a view that is several branches down the hierarchy tree. When more than one view uses the same tag, viewWithTag: returns the first item it finds.

The only challenge about using viewWithTag: is that it returns a UIView object. This means you often have to cast it to the proper type before you can use it. For example, you can retrieve a label and set its text ...