Question

I’m trying to create a container view controller using iOS5 and new methods like addChildViewController.

Do I have to call addSubview after calling addChildViewController?

Do I have to call removeFromSuperview before calling removeChildViewController?

I don’t see anything about this in Apple docs.
What do you think?

Answer 1

Short answer: “Yes, and yes.” The view hierarchy and the view controller hierarchy are still independent. The containment API simply allows views from other controllers to present themselves within a parent controller’s view in a clean and consistent way.

You can find a bit in Apple’s docs here… this is a relevant passage from the “Container View Controllers Arrange Content of Other View Controllers” section:

A container manages a view hierarchy just as other view controllers do. A container can also add the views of any of its children into its view hierarchy. The container decides when such a view is added and how it should be sized to fit the container’s view hierarchy, but otherwise the child view controller remains responsible for the view and its subviews.

If you have access, I would highly recommend checking out the WWDC 2011 video entitled “Implementing UIViewController Containment” (download it from Apple Developer Video Archive).