Question

Can I load a UiViewController in a UIView in another UIViewcontrller.

suppose UIViewControllerA has a UIView named subuiview. Can I load UIViewControllerB into subbuiview?

Thanks!

Answer 1

Starting with iOS 5

“Container view controllers” have been added in iOS 5. You can add a view controller as a child of another one with addChildViewController:.
You also are responsible for adding its view to its parent’s view.

Everything is well documented in the iOS SDK documentation: Implementing a Custom Container View Controller.

To add a child view controller:

childViewController.frame = ...
[self.view addSubview:childViewController.view];
[self addChildViewController:childViewController];
[childViewController didMoveToParentViewController:self];

and to remove it:

[self willMoveToParentViewController:nil];
[self.view removeFromSuperview];
[self removeFromParentViewController];

Prior to iOS 5

It’s possible to load another view controller and add its view as a subview of another controller’s view.

UIViewController *subController = ...
[self.view addSubview:subController.view];

Although it’s not recommended by Apple’s guidelines:

Each custom view controller object you
create is responsible for managing all
of the views in a single view
hierarchy. […] The one-to-one
correspondence between a view
controller and the views in its view
hierarchy is the key design
consideration. You should not use
multiple custom view controllers to
manage different portions of the same
view hierarchy.

(from the View Controller Programming Guide)

Your sub-controller won’t receive rotation events, or viewWillAppear, viewWillDisappear, etc (except viewDidLoad).

So Apple advises us to use a single view controller managing the entire view hierarchy (but doesn’t forbid to use multiple ones).

Each view may still be a custom subclass of UIView. Maybe you don’t need another view controller but rather a custom view.