Move emptyView API to a property on IGListAdapter

[rnystrom]

There's really no need for this to be a required method on IGListAdapterDataSource. It could simply be a property, defaulted to nil. When you set the property we use it when the adapter is empty.

Not sure if we need to bother what happens if you set the property after everything has been updated.

[jessesquires]

It could simply be a property...

A property on what? Not clear who the owner would be.

[rnystrom]

@jessesquires on IGListAdapter I think (or IGListCollectionView)

[jessesquires]

Ah. But then you'd have to alloc that view upfront (and potentially never use it)

[rnystrom]

This is true

[rnystrom]

Closing this as I think lazily loading the empty view, plus changing which view is returned based on state, is a better approach. It leaves us w/ a little more boilerplate but it keeps the functional nature of a lot of the infra.

[tunidev]

@rnystrom The empty view is conflict when you using something like this:
https://github.com/aschuch/StatefulViewController

so I hope that wether IGListKit provide a Loading, Error and Empty views or just remove emptyView or keep it optional

[weyert]

How would it conflict with it? I thought StatefulViewController doesn't mess around with the UICollectionView? Does it conflict with their UICollectionViewController hack?

As I always though it would the view state to the view of the UIViewController and not the UICollectionView?

[tunidev]

@weyert sorry for not being clear, I mean when I will use StatefulViewController I will not need the emptyView of IGListKit

[weyert]

Yes, so you can just return nil there?

[tunidev]

@weyert sure, but it will be confusing to have two different logic to handle empty state, hence the suggestion to make it optional like suggested in the initial issue

[weyert]

I think the idea is to switch away from optional's in the code base (@rnystrom correct?) so maybe it's better to have a default implementation which returns nil