View as SubView VS ChildViewController

Question

Can any one explain when should we add a UIViewController as ChildViewController?

What is the benefits of adding it as ChildViewController instead of subView?

Please help me to understand the purpose of ChildViewController.

Answer 1

When you add a view controller as child view controller, the parent view controller will hold a strong pointer to the child view controller so it doesn't get released instantly. This does not automatically add child's view to parent's view. So you will have to call them both.

I only used it when I needed to create multiple view controllers to be inserted in another view controller and didn't need to directly access it.

Answer 2

its all about UI and code management if you are using subview to achieve what you want to implement inside your app you need to code for your view inside same viewcontrollers class but something interesting i found by creating childviewcontrollers.

1. empowered to work on a seprate viewcontroller will invoked along with its parent viewcontroller along with its seprate class.
2. infinite controllers that will be updated tapping a button.

Creation of childViewControllers can be achived by implementing containerView.
or you must have a look of this link hope its helpful to understand.