The Apple guy in the What's new in Cocoa Touch WWDC video said that the new large-title navigation bar will magically hook into the top-level scroll view of the underlying view controller and collapse/expand itself automatically while scrolling up and down. (And by "magically", he probably meant that they failed to monkey patch this functionality into the already embarassing UINavigationController-UINavigationBar-UINavigationitem APIs in a usable way, so they had to resort to hooking into some heuristically chosen scroll view behind the scenes)
Even though I was prepared that this "automatic" collapse/expand wouldn't work if I deviate the slightest from the basic UINavigationController + UITableView/UICollectionView setup, it seems that even in this simplest case it doesn't work as expected.
Here's what I have:
A UITabBarController which contains a UINavigationController, which contains a UIViewController, which has a UITableView as its view. Tapping the first cell in the table will push a second view controller on the navigation stack:
No code, just the storyboard.
I've checked "Prefers large titles" for the navigation bar to activate large titles. Now, if I run the app and scroll up/down on the table view, the navigation bar stays the same - large - size; it doesn't collapse:
However, I've found that if I set the second view controller's navigation item to use the small navigation bar (by setting "Large Title" to the value "Never"), then if I open that page and navigate back, the interactive collapse magically starts working on the first page:
Am I missing something here, or is this feature not working properly? Here's the sample project I'm using: https://github.com/tzahola/iOS-11-Large-Title-Navigation-Bar
And by the way, I'm using the officially released iOS 11, not the betas.
2017-09-23 Update: I've sent a bug report to Apple, and opened a ticket on openradar.me: http://www.openradar.me/radar?id=5017601935671296
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
