Advances in CollectionViews

The talk covers the new layout included in iOS 13. The compositional layout which enables you to create complex layouts without writing a lot of boilerplate code.
Demo Link: https://github.com/rahuljain01/CompositionalLayout

Speakers: Vinita Miranda & Rahul Jain
Vinita has 7.5+ years of experience in iOS. Currently working as an iOS Developer at Dream11.
LinkedIn: https://www.linkedin.com/in/vinita-miranda-3874a824
Rahul Jain: https://www.linkedin.com/in/rahuljain01/

Presented at Swift Mumbai Chapter 9 Meetup hosted by Dream11
https://www.meetup.com/Swift-Mumbai/events/260541095/

Transcript

1. Compositional Layouts - Vinita Miranda & Rahul Jain
2. Weekly Leaderboard
3. Current Approach • Multiple collection view • Abstract classes • Line based layout.
4. Custom Layout Challenges • Boilerplate Code • Supplementary/ Decorations Views • Self-sizing challenges
5. Compositional Layout • Composible • Flexible • Fast
6. Compositional Layout • Composing small layouts • Line based layout • Composition instead of subclassing
7. Components in Compositional Layout • NSCollectionLayoutSize • NSCollectionLayoutItem • NSCollectionLayoutGroup • NSCollectionLayoutSection • NSCollectionViewCompositionalLayout
9. Item -> Group -> Section -> Layout Layout Section Group Item
10. NSCollectionLayoutSize • Width • Height
11. NSCollectionLayoutDimension
12. Fractional Width 0.5
13. NSCollectionLayoutDimension
16. NSCollectionLayoutItem
17. NSCollectionLayoutGroup
18. NSCollectionLayoutSection
19. UICollectionViewCompositionalLayout
20. Current Collection Data Source
21. Controller UI Number of items Web Service Response Did Change
22. Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of sections. The number of sections contained in the collection view after the update (10) must be equal to the number of sections contained in the collection view before the update (10), plus or minus the number of sections inserted or deleted (0 inserted, 1 deleted).
23. UICollectionViewDiffableDataSource • Apply is used instead of performBatchUpdates.
24. NSDiffableDataSourceSnapshot • Unique identifiers for section and items. • No indexPath needed
25. Identifiers • Must be unique • Must conform to hashable
26. Demo