Fix CustomCollectionView-Swift sample

[george-gw]

The sample was crashing, the crash was reported on Slack.
This is a quick fix

[CLAassistant]

All committers have signed the CLA.

[maicki]

@Adlai-Holler Did this change due to our initializer changes?

[Adlai-Holler]

@george-gw @maicki Could someone link to the Slack conversation about the issue, and open a GitHub issue for it? I searched around but couldn't find it.

[george-gw]

@Adlai-Holler #39

[maicki]

@Adlai-Holler Any thoughts on it based on the issue? Did the initializer changed due to our changes?

[maicki]

Following up with that, this change does not have anything to do with the initializer change @Adlai-Holler did a while back.

The reason looking into it bit more actually is:
The collection node get's allocated with CGSize.zero in init and the frame get
s updated in viewWillLayoutSubviews in the view controller. Unfortunately a layout pass get’s through before viewWillLayoutSubviews occur and the frame of the collection node is CGSize.zero . Unfortunately the collection layout calculates the size of an item via collectionView.bounds.size.width - sectionInsets.width * 2 or similar. The result is that we get a minus width and the whole thing crashes as we try to layout a node that does not have a valid size.

Another resolution would be if we would not move to ASViewController is to do something like that:

  required init?(coder aDecoder: NSCoder) {
    let layout = MosaicCollectionViewLayout()
    layout.numberOfColumns = 3;
    layout.headerHeight = 44;
    _collectionNode = ASCollectionNode(frame: CGRect.zero, collectionViewLayout: layout)
    
    super.init(coder: aDecoder)
    
    layout.delegate = self
    
    _sections.append([]);
    var section = 0
    for idx in 0 ..< kNumberOfImages {
      let name = String(format: "image_%d.jpg", idx)
      _sections[section].append(UIImage(named: name)!)
      if ((idx + 1) % 5 == 0 && idx < kNumberOfImages - 1) {
        section += 1
        _sections.append([])
      }
    }
  }
  
  override func viewDidLoad() {
    super.viewDidLoad()
    
    _collectionNode.frame = self.view.bounds;
    _collectionNode.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    _collectionNode.dataSource = self;
    _collectionNode.delegate = self;
    _collectionNode.backgroundColor = UIColor.white
    _collectionNode.registerSupplementaryNode(ofKind: UICollectionElementKindSectionHeader)
    _collectionNode.view.isScrollEnabled = true
    _collectionNode.view.layoutInspector = _layoutInspector
    self.view.addSubnode(_collectionNode!)
  }

[maicki]

@george-gw Thanks for fixing that. Will merge now.