The document provides an overview of Collection View in iOS. It describes the key classes like UICollectionView, UICollectionViewCell, UICollectionViewLayout and protocols like UICollectionViewDataSource and UICollectionViewDelegate. It covers concepts like registering cells and views, performing batch updates, flow layout, custom layouts, interactive reordering and improvements in iOS 10 and 13 like self-sizing cells, prefetching and diffable data sources. Code examples are provided to demonstrate implementation of collection views.

1. Collection View

2. Collection View ?
Collection View

3. ' ?'
Collection View

4. -
-
-
?
-
-
- Layout? Flow Layout?
-
- ?
Collection View

5. !
Collection View

6. iOS 10
iOS 13
Collection View

7. Collection View

8. Collection View
Collection View
-
-
-
-
- Grid View Collection View
-
-
-

9. Collection View
UICollectionView
UICollectionViewController
UICollectionViewDataSource
UICollectionViewDelegate
UICollectionReusableView
UICollectionViewCell
UICollectionViewLayout
UICollectionViewLayoutAttributes
UICollectionViewUpdateItem
UICollectionViewFlowLayout
UICollectionViewDelegateFlowLayout

10. Collection View
- class UICollectionView
-
-
- UIScrollView
- class UICollectionViewController
- View Controller
- UIViewController

11. Collection View
- protocol UICollectionViewDataSource
-
- ,
-
- protocol UICollectionViewDelegate
-
-
-
-

12. Collection View
- class UICollectionReusableView
-
-
- class UICollectionViewCell
-
- UICollectionReusableView

13. Collection View
- class UICollectionViewLayout
-
- , , ,
- class UICollectionViewLayoutAttributes
-
- ,
- class UICollectionViewUpdateItem
- , ,
-

14. Collection View
- class UICollectionViewFlowLayout
-
- ,
- UICollectionViewLayout
- protocol UICollectionViewDelegateFlowLayout
-
- UICollectionViewDelegate

15. Collection View
Cell
Supplementary View
Decoration View

16. Collection View
Cell
-
-
-

17. Collection View
Supplementary View
-
-
-
-

18. Collection View
Decoration View
-
-
-
-

19. Collection View
-
- , ,
- ,
- ! .
- , ,

20. Collection View
- , ,
- ,
-

21. Collection View
- ?
- numberOfSections(in:)
- ?
- collectionView(_:numberOfItemsInSection:)
- ?
- collectionView(_:cellForItemAt:)
- collectionView(_:viewForSupplementaryElementOfKind:at:)

22. Collection View
-
-
- 1-depth : Section
- 2-depth : Item
-
[[1, 2], [3, 4, 5], [6, 7, 8, 9]]
- 3
- 2, 3, 4

23. Collection View
-
-
- reloadData()
- performBatchUpdates(_:completion:) , , ,

24. Collection View
- register(_:withReuseIdentifier:)
- register(_:forSupplementaryViewOfKind:withReuseIdentifier:)
- collectionView(_:cellForItemAt:)
- collectionView(_:viewForSupplementaryElementOfKind:at:)
- dequeueReusableCell(withReuseIdentifier:for:)
- dequeueReusableSupplementaryView(ofKind:withReuseIdentifier:for:)

25. Collection View
- ,
- ,
- , (UINib.instantiate / init(frame:))
- ,
-
- prepareForReuse()

26. - register(_:withReuseIdentifier:)
- register(_:forSupplementaryViewOfKind:withReuseIdentifier:)
- collectionView(_:cellForItemAt:)
- collectionView(_:viewForSupplementaryElementOfKind:at:)
- dequeueReusableCell(withReuseIdentifier:for:)
- dequeueReusableSupplementaryView(ofKind:withReuseIdentifier:for:)
Collection View

27. Collection View
Kind String
- kind
- UICollectionViewFlowLayout , ,
UICollectionView Kind String
- UICollectionView.elementKindSectionHeader
- UICollectionView.elementKindSectionFooter
-

28. Collection View
, ,
1.
2. , ,
- performBatchUpdates(_:completion:)
- ,

29. Collection View
- UITableViewCell.selectionStyle
-
-
-

30. Collection View
TableLikeCollectionViewController.swift

31. Collection View
- ( -> )
- , true false
- , false true
-
- true
- false

32. Collection View
UICollectionViewCell
- backgroundView
- selectedBackgroundView
UICollectionViewDelegate
- collectionView(_:shouldSelectItemAt:)
- collectionView(_:shouldDeselectItemAt:)
- collectionView(_:didSelectItemAt:)
- collectionView(_:didDeselectItemAt:)
- collectionView(_:shouldHighlightItemAt:)
- collectionView(_:didHighlightItemAt:)
- collectionView(_:didUnhighlightItemAt:)

33. Collection View
UICollectionViewDelegate
- collectionView(_:shouldShowMenuForItemAt:)
- collectionView(_:canPerformAction:forItemAt:withSender:)
- collectionView(_:performAction:forItemAt:withSender:)
iOS 13 deprecated -> Context Menu

34. Collection View

35. Collection View
iOS 10

36. Collection View
iOS 10
Cell ( ) (iOS 10 )
1. prepareForReuse()
2. collectionView(_:willDisplay:forItemAt:)
3. collectionView(_:didEndDisplaying:forItemAt:)
4.

37. Collection View
iOS 10
Cell ( ) (iOS 10 )
1. prepareForReuse()
2. collectionView(_:willDisplay:forItemAt:)
3. collectionView(_:didEndDisplaying:forItemAt:)
4.
• ,
prepareForReuse() collectionView(_:willDisplay:forItemAt:)
.

38. Collection View
iOS 10
Pre-Fetching
protocol UICollectionViewDataSourcePrefetching
collectionView(_:prefetchItemsAt:)
collectionView(_:cancelPrefetchingForItemsAt:)
isPrefetchingEnabled
prefetchDataSource
- ,
-
-
- Prefetch ,
- Prefetch ,
-

39. Collection View
iOS 10
Self-Sizing Cell
UICollectionViewFlowLayout
- UICollectionViewFlowLayout.automaticSize
- UICollectionViewFlowLayout.estimatedItemSize ,
- CGSize.zero

40. Collection View
iOS 10
Interactive Reordering
- collectionView(_:canMoveItemAt:)
- collectionView(_:moveItemAt:to:)

41. Collection View
iOS 10
Interactive Reordering
UICollectionViewController
-installsStandardGestureForInteractiveMovement true
- true
UICollectionView
- UILongPressGesture
- ,
-beginInteractiveMovementForItem(at:)
-updateInteractiveMovementTargetPosition(_:)
-endInteractiveMovement()
-cancelInteractiveMovement()

42. Collection View
iOS 10
Interactive Reordering

43. Collection View
iOS 10
Interactive Reordering

44. Collection View
iOS 10
Interactive Reordering
InteractiveReorderingCollectionViewController.swift

45. Collection View

46. Collection View
class UICollectionViewFlowLayout
- UICollectionViewLayout
-
-itemSize
- minimumLineSpacingForSection /
minimumInteritemSpacingForSection / insetForSection
- referenceSizeForHeader / referenceSizeForFooter

47. Collection View
protocol UICollectionViewDelegateFlowLayout
- UICollectionViewDelegate
-
-
- ,

48. Collection View
UICollectionViewDelegateFlowLayout
Methods
UICollectionViewFlowLayout
Properties
collectionView(_:layout:sizeForItemAt:) itemSize
collectionView(_:
layout:minimumLineSpacingForSectionAt:)
minimumLineSpacing
collectionView(_:
layout:minimumInteritemSpacingForSectionAt:)
minimumInteritemSpacing
collectionView(_:layout:insetForSectionAt:) insetForSection
collectionView(_:
referenceSizeForHeaderInSection:)
referenceSizeForHeader
collectionView(_:
referenceSizeForFooterInSection:)
referenceSizeForFooter

49. Collection View
Line
- ,
- ,
- ,

50. Collection View
Inter-Item Spacing
-
- ,
- ,
- minimumInteritemSpacing
Line Spacing
-
- ,
- ,
- minimumLineSpacing

51. Collection View
.
-
-
-
-

52. Collection View
- .
- .
- ,
.
layoutAttributesForElements(in:)
layoutAttributesForItem(at:)
layoutAttributesForSupplementaryView(ofKind:at:)
layoutAttributesForDecorationView(ofKind:at:)

53. Collection View
-
layoutAttributesForElements(in:)

54. Collection View
-
.
UICollectionViewLayoutAttributes
layoutAttributesClass
layoutAttributesForElements(in:)
layoutAttributesForItem(at:)

55. Collection View
- .
initialLayoutAttributesForAppearingItem(at:)
initialLayoutAttributesForAppearingSupplementaryElement(ofKind:at:)
initialLayoutAttributesForAppearingDecorationItem(ofKind:at:)
finalLayoutAttributesForDisappearingItem(at:)
finalLayoutAttributesForDisappearingSupplementaryItem(ofKind:at:)
finalLayoutAttributesForDisappearingDecorationItem(ofKind:at:)

56. Collection View
UICollectionViewLayout
-
-

57. Collection View
-
-

58. Collection View
- invalidateLayout()
- reloadData()
-
1. prepare()
2. collectionViewContentSize
3. layoutAttributesForElements(in:)

59. Collection View
prepare()
-
-

60. Collection View
collectionViewContentSize
-
- UICollectionViewFlowLayout ,
UICollectionViewLayout

61. Collection View
layoutAttributesForElements(in:)
- ,
- UICollectionViewLayoutAttributes
- init(forCellWith:)
- init(forSupplementaryViewOfKind:with:)
- init(forDecorationViewOfKind:with:)

62. Collection View
- invalidate
- invalidateLayout()
- shouldInvalidateLayout(forBoundsChange:)
- bounds invalidate
- false

63. Collection View
prepare(forCollectionViewUpdates:)
finalizeCollectionViewUpdates()
initialLayoutAttributesForAppearingItem(at:)
initialLayoutAttributesForAppearingSupplementaryElement(ofKind:at:)
initialLayoutAttributesForAppearingDecorationElement(ofKind:at:)
finalLayoutAttributesForDisappearingItem(at:)
finalLayoutAttributesForDisappearingSupplementaryElement(ofKind:at:)
finalLayoutAttributesForDisappearingDecorationElement(ofKind:at:)

64. Collection View
targetContentOffset(forProposedContentOffset:)
targetContentOffset(forProposedContentOffset:withScrollingVelocity:)

65. Collection View

66. Collection View

67. Collection View

68. Collection View

69. Collection View

70. Collection View
CustomFlowLayoutViewController.swift

71. Collection View
,

72. Collection View

73. Collection View

74. Collection View

75. Collection View

76. Collection View
CustomLayoutViewController.swift

77. Collection View
iOS 13

78. Collection View
iOS 13
UICollectionViewDiffableDateSource
RxDataSources / kickstarter/ios-oss

79. class UICollectionViewDiffableDataSource
<SectionIdentifierType: Hashable, ItemIdentifierType: Hashable>
: NSObject, UICollectionViewDataSource
init(collectionView:cellProvider:)
supplementaryViewProvider
apply(_:animatingDifferences:completion:)
Collection View
iOS 13
UICollectionViewDiffableDateSource

80. struct NSDiffableDataSourceSnapshot
<SectionIdentifierType: Hashable, ItemIdentifierType: Hashable>
numberOfItems
numberOfItems(inSection:)
numberOfSections
sectionIdentifiers
itemIdentifiers
itemIdentifiers(inSection:)
sectionIdentifiers(containingItem:)
appendItems(_:toSection:)
insertItems(_:beforeItem:)
insertItems(_:afterItem:)
deleteItems(_:)
deleteAllItems()
moveItem(_:beforeItem:)
moveItem(_:afterItem:)
reloadItems(_:)
appendSections(_:)
insertSections(_:beforeSection:)
insertSections(_:afterSection:)
deleteSections(_:)
deleteAllSections()
moveSection(_:beforeSection:)
moveSection(_:afterSection:)
reloadSections(_:)
Collection View
iOS 13
UICollectionViewDiffableDateSource

81. Collection View
iOS 13
UICollectionViewDiffableDateSource

82. Collection View
iOS 13
UICollectionViewDiffableDateSource

83. Collection View
iOS 13
UICollectionViewDiffableDateSource

84. Collection View
iOS 13
UICollectionViewDiffableDateSource

85. performBatchUpdates(_:completion:)
-
-
-
-
- Index Path
-
reloadData()
-
-
-
Collection View
iOS 13
UICollectionViewDiffableDateSource

86. UICollectionViewDiffableDataSource ?
- apply() !
-
Collection View
iOS 13
UICollectionViewDiffableDateSource

87. BeforeDiffableDataSourceViewController.swift
AfterDiffableDataSourceViewController.swift
Collection View
iOS 13
UICollectionViewDiffableDateSource

88. UICollectionViewLayout
,
Collection View
iOS 13
UICollectionViewCompositionalLayout

89. Dimension -> Size -> Item -> Group -> Section -> Layout
Collection View
iOS 13
UICollectionViewCompositionalLayout

90. Dimension -> Size -> Item -> Group -> Section -> Layout
NSCollectionLayoutDimension
- ,
absolute(_:)
estimated(_:)
fractionalWidth(_:)
fractionalHeight(_:)
Collection View
iOS 13
UICollectionViewCompositionalLayout

91. NSCollectionLayoutSize
-
init(widthDimension:heightDimension:)
Dimension -> Size -> Item -> Group -> Section -> Layout
Collection View
iOS 13
UICollectionViewCompositionalLayout

92. NSCollectionLayoutItem
-
init(layoutSize:)
contentInsets
edgeSpacing
init(layoutSize:supplementaryItems:)
Dimension -> Size -> Item -> Group -> Section -> Layout
Collection View
iOS 13
UICollectionViewCompositionalLayout

93. NSCollectionLayoutGroup
-
- NSCollectionLayoutItem :
horizontal(layoutSize:subitem:count:)
horizontal(layoutSize:subitems:)
vertical(layoutSize:subitem:count:)
vertical(layoutSize:subitems:)
interItemSpacing
supplementaryItems
Dimension -> Size -> Item -> Group -> Section -> Layout
Collection View
iOS 13
UICollectionViewCompositionalLayout

94. NSCollectionLayoutSection
-
init(group:)
contentInsets
interGroupSpacing
orthogonalScrollingBehavior
boundarySupplementaryItems
decorationItems
Dimension -> Size -> Item -> Group -> Section -> Layout
Collection View
iOS 13
UICollectionViewCompositionalLayout

95. UICollectionViewCompositionalLayout
-
init(section:)
init(section:configuration:)
init(sectionProvider:)
init(sectionProvider:configuration:)
Dimension -> Size -> Item -> Group -> Section -> Layout
Collection View
iOS 13
UICollectionViewCompositionalLayout

96. Collection View
iOS 13
UICollectionViewCompositionalLayout

97. Collection View
iOS 13
UICollectionViewCompositionalLayout

98. Collection View
iOS 13
UICollectionViewCompositionalLayout

99. Collection View
iOS 13
UICollectionViewCompositionalLayout

100. Collection View
iOS 13
UICollectionViewCompositionalLayout

101. Collection View
iOS 13
UICollectionViewCompositionalLayout

102. Collection View
iOS 13
UICollectionViewCompositionalLayout

103. Collection View
iOS 13
UICollectionViewCompositionalLayout
SimpleCompositionalLayoutViewController.swift

104. NSCollectionLayoutSection.orthogonalScrollingBehavior
Collection View
iOS 13
UICollectionViewCompositionalLayout

105. enum NSCollectionLayoutSectionOrthogonalScrollingBehavior {
case continuous
case continuousGroupLeadingBoundary
case paging
case groupPaging
case groupPagingCentered
case none
}
Collection View
iOS 13
UICollectionViewCompositionalLayout

106. Collection View
iOS 13
UICollectionViewCompositionalLayout

107. Collection View
iOS 13
UICollectionViewCompositionalLayout

108. Collection View
iOS 13
UICollectionViewCompositionalLayout

109. continous
-
Collection View
iOS 13
UICollectionViewCompositionalLayout

110. continousGroupLeadingBoundary
-
- leading
Collection View
iOS 13
UICollectionViewCompositionalLayout

111. paging
-
Collection View
iOS 13
UICollectionViewCompositionalLayout

112. groupPaging
-
-
Collection View
iOS 13
UICollectionViewCompositionalLayout

113. groupPagingCentered
-
-
Collection View
iOS 13
UICollectionViewCompositionalLayout

114. none
-
Collection View
iOS 13
UICollectionViewCompositionalLayout

115. OrthogonalScrollBehaviorCompositionalLayoutViewController.swift
Collection View
iOS 13
UICollectionViewCompositionalLayout

116. API
Diffable Data Source / Compositional Layout
Collection View

117. Collection View Programming Guide for iOS
[https://developer.apple.com/library/archive/documentation/WindowsViews/
Conceptual/CollectionViewPGforIOS]
WWDC 2016 : What's New in UICollectionView in iOS 10
[https://developer.apple.com/videos/play/wwdc2016/219/]
WWDC 2018 : A Tour of UICollectionView
[https://developer.apple.com/videos/play/wwdc2018/225/]
WWDC 2019 : Advances in Collection View Layout
[https://developer.apple.com/videos/play/wwdc2019/215/]
WWDC 2019 : Advances in UI Data Sources
[https://developer.apple.com/videos/play/wwdc2019/220/]
Collection View

118. Using Collection View Compositional Layouts and Diffable Data Sources
[https://developer.apple.com/documentation/uikit/views_and_controls/
collection_views/
using_collection_view_compositional_layouts_and_diffable_data_sources]
CollectionViewExamples
[https://github.com/presto95/CollectionViewExamples]
Collection View

119. .