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< p > < a href = "index.html" > IGListKit 4.1.0 Docs< / a > (93% documented)< / p >
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Working with UICollectionView Reference
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< a href = "Constants.html#/c:@IGListKitVersionNumber" > IGListKitVersionNumber< / a >
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< a href = "Constants.html#/c:@IGListKitVersionString" > IGListKitVersionString< / a >
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< a href = "Enums/IGListDiffOption.html" > IGListDiffOption< / a >
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< a href = "Protocols/IGListAdapterDelegate.html" > IGListAdapterDelegate< / a >
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< a href = "Protocols/IGListAdapterUpdateListener.html" > IGListAdapterUpdateListener< / a >
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< a href = "Protocols/IGListAdapterUpdaterDelegate.html" > IGListAdapterUpdaterDelegate< / a >
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< a href = "Protocols/IGListCollectionViewDelegateLayout.html" > IGListCollectionViewDelegateLayout< / a >
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< a href = "Protocols/IGListDiffable.html" > IGListDiffable< / a >
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< a href = "Protocols/IGListUpdatingDelegate.html" > IGListUpdatingDelegate< / a >
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< a href = "Type%20Definitions/IGListCollectionScrollingTraits.html" > IGListCollectionScrollingTraits< / a >
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< a href = "Type%20Definitions.html#/c:IGListUpdatingDelegate.h@T@IGListCollectionViewBlock" > IGListCollectionViewBlock< / a >
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< a href = "Type%20Definitions.html#/c:IGListUpdatingDelegate.h@T@IGListDataSourceChangeBlock" > IGListDataSourceChangeBlock< / a >
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< a href = "Type%20Definitions.html#/c:IGListUpdatingDelegate.h@T@IGListItemUpdateBlock" > IGListItemUpdateBlock< / a >
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< a href = "Type%20Definitions.html#/c:IGListUpdatingDelegate.h@T@IGListObjectTransitionBlock" > IGListObjectTransitionBlock< / a >
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< a href = "Type%20Definitions.html#/c:IGListUpdatingDelegate.h@T@IGListReloadUpdateBlock" > IGListReloadUpdateBlock< / a >
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< article class = "main-content" >
< section >
< section class = "section" >
< h1 id = 'working-with-code-uicollectionview-code' class = 'heading' > Working with < code > UICollectionView< / code > < / h1 >
< p > This guide provides details on how to work with < a href = "https://developer.apple.com/reference/uikit/uicollectionview" > < code > UICollectionView< / code > < / a > and < code > IGListKit< / code > .< / p >
< h2 id = 'background' class = 'heading' > Background< / h2 >
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< p > Early versions of < code > IGListKit< / code > (2.x and prior) shipped with a subclass of < code > UICollectionView< / code > called < a href = "https://github.com/Instagram/IGListKit/blob/2.1.0/Source/IGListCollectionView.h" > < code > < a href = "Classes/IGListCollectionView.html" > IGListCollectionView< / a > < / code > < / a > . The class contained < em > no< / em > special functionality and was merely used to enforce compile-time restrictions to prevent users from calling certain methods directly on < code > UICollectionView< / code > . Beginning with 3.0, < code > < a href = "Classes/IGListCollectionView.html" > IGListCollectionView< / a > < / code > < a href = "https://github.com/Instagram/IGListKit/commit/2284ce389708f62d99f48ff2ec15644f1ec59537" > was removed< / a > for a number of reasons.< / p >
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< p > For further discussion see < a href = "https://github.com/Instagram/IGListKit/issues/240" > #240< / a > and < a href = "https://github.com/Instagram/IGListKit/issues/409" > #409< / a > .< / p >
< h2 id = 'methods-to-avoid' class = 'heading' > Methods to avoid< / h2 >
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< p > One of the primary purposes of < code > IGListKit< / code > is to perform optimal batch updates for < code > UICollectionView< / code > . Thus, clients < strong > should never< / strong > call any APIs on < code > UICollectionView< / code > that involved reloading, inserting, deleting, or otherwise updating cells and index paths. Instead, use the APIs provided by < a href = "https://instagram.github.io/IGListKit/Classes/IGListAdapter.html" > < code > < a href = "Classes/IGListAdapter.html" > IGListAdapter< / a > < / code > < / a > . You should also avoid setting the < a href = "https://developer.apple.com/reference/uikit/uicollectionview/1618033-delegate" > < code > delegate< / code > < / a > and < a href = "https://developer.apple.com/reference/uikit/uicollectionview/1618091-datasource" > < code > dataSource< / code > < / a > of the collection view, as this is also the responsibility of < code > < a href = "Classes/IGListAdapter.html" > IGListAdapter< / a > < / code > .< / p >
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< p > Avoid calling the following methods:< / p >
< pre class = "highlight objective_c" > < code > < span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > performBatchUpdates< / span > < span class = "p" > :(< / span > < span class = "kt" > void< / span > < span class = "p" > (< / span > < span class = "o" > ^< / span > < span class = "p" > )(< / span > < span class = "kt" > void< / span > < span class = "p" > ))< / span > < span class = "nv" > updates< / span >
< span class = "nf" > completion< / span > < span class = "p" > :(< / span > < span class = "kt" > void< / span > < span class = "p" > (< / span > < span class = "o" > ^< / span > < span class = "p" > )(< / span > < span class = "n" > BOOL< / span > < span class = "p" > ))< / span > < span class = "nv" > completion< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "n" > reloadData< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > reloadSections< / span > < span class = "p" > :(< / span > < span class = "n" > NSIndexSet< / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > sections< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > insertSections< / span > < span class = "p" > :(< / span > < span class = "n" > NSIndexSet< / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > sections< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > deleteSections< / span > < span class = "p" > :(< / span > < span class = "n" > NSIndexSet< / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > sections< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > moveSection< / span > < span class = "p" > :(< / span > < span class = "n" > NSInteger< / span > < span class = "p" > )< / span > < span class = "nv" > section< / span > < span class = "nf" > toSection< / span > < span class = "p" > :(< / span > < span class = "n" > NSInteger< / span > < span class = "p" > )< / span > < span class = "nv" > newSection< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > insertItemsAtIndexPaths< / span > < span class = "p" > :(< / span > < span class = "n" > NSArray< / span > < span class = "o" > < < / span > < span class = "n" > NSIndexPath< / span > < span class = "o" > *> < / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > indexPaths< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > reloadItemsAtIndexPaths< / span > < span class = "p" > :(< / span > < span class = "n" > NSArray< / span > < span class = "o" > < < / span > < span class = "n" > NSIndexPath< / span > < span class = "o" > *> < / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > indexPaths< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > deleteItemsAtIndexPaths< / span > < span class = "p" > :(< / span > < span class = "n" > NSArray< / span > < span class = "o" > < < / span > < span class = "n" > NSIndexPath< / span > < span class = "o" > *> < / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > indexPaths< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > moveItemAtIndexPath< / span > < span class = "p" > :(< / span > < span class = "n" > NSIndexPath< / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > indexPath< / span > < span class = "nf" > toIndexPath< / span > < span class = "p" > :(< / span > < span class = "n" > NSIndexPath< / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > newIndexPath< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > setDelegate< / span > < span class = "p" > :(< / span > < span class = "n" > id< / span > < span class = "o" > < < / span > < span class = "n" > UICollectionViewDelegate< / span > < span class = "o" > > < / span > < span class = "p" > )< / span > < span class = "nv" > delegate< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > setDataSource< / span > < span class = "p" > :(< / span > < span class = "n" > id< / span > < span class = "o" > < < / span > < span class = "n" > UICollectionViewDataSource< / span > < span class = "o" > > < / span > < span class = "p" > )< / span > < span class = "nv" > dataSource< / span > < span class = "p" > ;< / span >
< span class = "k" > -< / span > < span class = "p" > (< / span > < span class = "kt" > void< / span > < span class = "p" > )< / span > < span class = "nf" > setBackgroundView< / span > < span class = "p" > :(< / span > < span class = "n" > UIView< / span > < span class = "o" > *< / span > < span class = "p" > )< / span > < span class = "nv" > backgroundView< / span > < span class = "p" > ;< / span >
< / code > < / pre >
< h2 id = 'performance' class = 'heading' > Performance< / h2 >
< p > In iOS 10, a new < a href = "https://developer.apple.com/reference/uikit/uicollectionviewdatasourceprefetching" > cell prefetching API< / a > was introduced. At Instagram, enabling this feature substantially degraded scrolling performance. We recommend setting < a href = "https://developer.apple.com/reference/uikit/uicollectionview/1771771-isprefetchingenabled" > < code > isPrefetchingEnabled< / code > < / a > to < code > NO< / code > (< code > false< / code > in Swift). Note that the default value is < code > true< / code > .< / p >
< p > You can set this globally using < code > UIAppearance< / code > :< / p >
< pre class = "highlight objective_c" > < code > < span class = "k" > if< / span > < span class = "p" > ([[< / span > < span class = "n" > UICollectionView< / span > < span class = "nf" > class< / span > < span class = "p" > ]< / span > < span class = "nf" > instancesRespondToSelector< / span > < span class = "p" > :< / span > < span class = "k" > @selector< / span > < span class = "p" > (< / span > < span class = "nf" > setPrefetchingEnabled< / span > < span class = "p" > :)])< / span > < span class = "p" > {< / span >
< span class = "p" > [[< / span > < span class = "n" > UICollectionView< / span > < span class = "nf" > appearance< / span > < span class = "p" > ]< / span > < span class = "nf" > setPrefetchingEnabled< / span > < span class = "p" > :< / span > < span class = "nb" > NO< / span > < span class = "p" > ];< / span >
< span class = "p" > }< / span >
< / code > < / pre >
< pre class = "highlight swift" > < code > < span class = "k" > if< / span > < span class = "kd" > #available(iOS 10, *)< / span > < span class = "p" > {< / span >
< span class = "kt" > UICollectionView< / span > < span class = "o" > .< / span > < span class = "nf" > appearance< / span > < span class = "p" > ()< / span > < span class = "o" > .< / span > < span class = "n" > isPrefetchingEnabled< / span > < span class = "o" > =< / span > < span class = "kc" > false< / span >
< span class = "p" > }< / span >
< / code > < / pre >
< / section >
< / section >
< section id = "footer" >
2023-04-07 07:23:43 +00:00
< p > © 2023 < a class = "link" href = "https://twitter.com/MetaOpenSource" target = "_blank" rel = "external noopener" > Instagram< / a > . All rights reserved. (Last updated: 2023-04-07)< / p >
< p > Generated by < a class = "link" href = "https://github.com/realm/jazzy" target = "_blank" rel = "external noopener" > jazzy ♪♫ v0.14.3< / a > , a < a class = "link" href = "https://realm.io" target = "_blank" rel = "external noopener" > Realm< / a > project.< / p >
2017-05-12 14:19:12 +00:00
< / section >
< / article >
< / div >
< / body >
< / html >
