Is it wise to “nest” UIViewControllers inside other UIViewControllers like you would UIViews?

Question

I\'ve got a fairly complex view, for me anyway, that has a few \"trays\" with custom interface items on them. They slide in and out of my root view. I\'d like to nest (addSu

Answer 1

I'm trying to do the same thing, but was dissuaded from your approach by Apple's documentation, which states that "You should not use view controllers to manage views that fill only a part of their window—that is, only part of the area defined by the application content rectangle. If you want to have an interface composed of several smaller views, embed them all in a single root view and manage that view with your view controller."

Answer 2

My experience on what you are trying to do has been a good one. I try to keep nib files as simple as possible, so I take any posible "subview" and encapsulate it in its own nib file with it's own view controller, therefore I end up having nested view controllers. In one of my apps I have a very complex table view cell, that has a subview. So I ended up having a hierarchy that goes like this: the tableview controller on the top level, the tableviewcell's controllers for each row and inside each of these a subviewcontroller for the subview inside each cell.

And everything works fine.

Pardon my english.

Answer 3

Prior to iOS 5.0 this will specifically not recommended because the nested view controllers' lifecycle events – viewWillAppear, etc. – won't be called. See Abusing UIViewControllers.

With multiple UIViewController’s views visible at once some of those controllers may not receive important messages like -viewWillAppear: or -didReceiveMemoryWarning. Additionally some of their properties like parentViewController and interfaceOrientation may not be set or updated as expected.

iOS 5.0 added containment UIViewControllers that correctly handles those lifecycle events by adding child view controllers.

- (void)addChildViewController:(UIViewController *)childController

I spent countless hours trying to get nested view controllers to work in iOS 4. I eventually did, but it required a lot of glue code that was easy to get wrong. Then I saw the warning in the docs.