What is top level object in XIb file mentioned in the book


in the book this was mentioned
“Notice that headerView is a strong property. This is because it will be a top-level object in the XIB file; you use weak references for objects that are owned (directly or indirectly) by the top-level objects”

Excerpt From: Keur, Christian. “iOS Programming: The Big Nerd Ranch Guide (4th Edition) (Big Nerd Ranch Guides).” iBooks.

what does top-level object in the XIB file mean? how do you know that the headerView property will be the top-level object in XIB file?


Top level views in a XIB are views that do not have a superview. An example might help - take a look at this screen shot: cl.ly/image/3L1t0N2c1c0g


Thanks a lot !