Best Practice: UIViewController or UIView

Question

I am gonna design a component in IOS, in which we will have Table view and Grid View; means user can see his data in table or grid. So what i am doing is i added a UIViewController and added two child view controller one for table and another one for collection view. I am handling everything using UIViewController only. Its means when user wants to use my component he has to add as a child view controller only. My question is that "Is it the best practice to use UIViewController like i am doing or Should I convert everything to UIView because UIView is light weight." I am gonna write only presentation logic in my component. We will get data from outside using delegate. And if i should use UIView then when should i use UIViewController?

Thanks

Answer 1

Your current approach is correct.

UIViews should do one and only one thing: paint a view when asked to.

UIViewControllers are more complex. They are are responsible for setting up views with any data they need to do their job, compositing multiple views (or view controllers) together if needed, responding to events from view components or from the device in general, and communicating with the rest of the code/system.

Because your code wants to show two different kinds of information, it fits the UIViewController much better than the plain UIView style.

As you've pointed out, Apple themselves have many examples of UIView subclasses that have delegates and do complex things. However, if you're writing a new component and it is complex (as yours is), I seriously recommend going for the UIViewController approach.

A note on history: Apple used to be of the advice that UIViewControllers should only show/composit UIViews and not other UIViewControllers (even though, confusingly, they didn't always follow their own advice!). This would align with their making of some quite complex UIView subclasses. However, they changed this stance a while back, and added support to UIViewControllers for compositing other UIViewControllers' views inside them. If Apple's stance had always been as it is now, you might find that some of their UIView subclasses were implemented as UIViewControllers!

As an experiment, it would probably be quite educational to try and implement your component both ways. I predict that you'd find UIView approach more unwieldy, with you having manually re-plumb some of the 'wiring' that you'd get 'for free' with the UIViewController approach.

Answer 2

Avoid putting logic in UIView subclass.