apple.uikit

Class UICollectionViewLayout

java.lang.Object

org.moe.natj.general.NativeObject

org.moe.natj.objc.ObjCObject

apple.NSObject

apple.uikit.UICollectionViewLayout

All Implemented Interfaces:

NSCoding, NSObject

Direct Known Subclasses:

UICollectionViewCompositionalLayout, UICollectionViewFlowLayout, UICollectionViewTransitionLayout

public class UICollectionViewLayout
extends NSObject
implements NSCoding

Nested Class Summary

Nested classes/interfaces inherited from class apple.NSObject

NSObject.Function_instanceMethodForSelector_ret, NSObject.Function_methodForSelector_ret

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	UICollectionViewLayout(org.moe.natj.general.Pointer peer)

Method Summary

Modifier and Type	Method and Description
static boolean	accessInstanceVariablesDirectly()
static UICollectionViewLayout	alloc()
static UICollectionViewLayout	allocWithZone(org.moe.natj.general.ptr.VoidPtr zone)
static boolean	automaticallyNotifiesObserversForKey(java.lang.String key)
static void	cancelPreviousPerformRequestsWithTarget(java.lang.Object aTarget)
static void	cancelPreviousPerformRequestsWithTargetSelectorObject(java.lang.Object aTarget, org.moe.natj.objc.SEL aSelector, java.lang.Object anArgument)
static NSArray<java.lang.String>	classFallbacksForKeyedArchiver()
static org.moe.natj.objc.Class	classForKeyedUnarchiver()
UICollectionView	collectionView() Methods in this class are meant to be overridden and will be called by its collection view to gather layout information.
CGSize	collectionViewContentSize() Subclasses must override this method and use it to return the width and height of the collection view’s content.
static java.lang.String	debugDescription_static()
static java.lang.String	description_static()
long	developmentLayoutDirection() Default implementation returns the layout direction of the main bundle's development region; FlowLayout returns leftToRight.
void	encodeWithCoder(NSCoder coder)
void	finalizeAnimatedBoundsChange() also called inside the animation block
void	finalizeCollectionViewUpdates() called inside an animation block after the update
void	finalizeLayoutTransition() called inside an animation block after the transition
UICollectionViewLayoutAttributes	finalLayoutAttributesForDisappearingDecorationElementOfKindAtIndexPath(java.lang.String elementKind, NSIndexPath decorationIndexPath)
UICollectionViewLayoutAttributes	finalLayoutAttributesForDisappearingItemAtIndexPath(NSIndexPath itemIndexPath)
UICollectionViewLayoutAttributes	finalLayoutAttributesForDisappearingSupplementaryElementOfKindAtIndexPath(java.lang.String elementKind, NSIndexPath elementIndexPath)
boolean	flipsHorizontallyInOppositeLayoutDirection() Base implementation returns false.
static long	hash_static()
NSArray<? extends NSIndexPath>	indexPathsToDeleteForDecorationViewOfKind(java.lang.String elementKind)
NSArray<? extends NSIndexPath>	indexPathsToDeleteForSupplementaryViewOfKind(java.lang.String elementKind) These methods are called by collection view during an update block.
NSArray<? extends NSIndexPath>	indexPathsToInsertForDecorationViewOfKind(java.lang.String elementKind)
NSArray<? extends NSIndexPath>	indexPathsToInsertForSupplementaryViewOfKind(java.lang.String elementKind)
UICollectionViewLayout	init()
UICollectionViewLayoutAttributes	initialLayoutAttributesForAppearingDecorationElementOfKindAtIndexPath(java.lang.String elementKind, NSIndexPath decorationIndexPath)
UICollectionViewLayoutAttributes	initialLayoutAttributesForAppearingItemAtIndexPath(NSIndexPath itemIndexPath) This set of methods is called when the collection view undergoes an animated transition such as a batch update block or an animated bounds change.
UICollectionViewLayoutAttributes	initialLayoutAttributesForAppearingSupplementaryElementOfKindAtIndexPath(java.lang.String elementKind, NSIndexPath elementIndexPath)
UICollectionViewLayout	initWithCoder(NSCoder coder) NS_DESIGNATED_INITIALIZER
static NSObject.Function_instanceMethodForSelector_ret	instanceMethodForSelector(org.moe.natj.objc.SEL aSelector)
static NSMethodSignature	instanceMethodSignatureForSelector(org.moe.natj.objc.SEL aSelector)
static boolean	instancesRespondToSelector(org.moe.natj.objc.SEL aSelector)
void	invalidateLayout() Call -invalidateLayout to indicate that the collection view needs to requery the layout information.
void	invalidateLayoutWithContext(UICollectionViewLayoutInvalidationContext context)
static org.moe.natj.objc.Class	invalidationContextClass() override this method to provide a custom class to be used for invalidation contexts
UICollectionViewLayoutInvalidationContext	invalidationContextForBoundsChange(CGRect newBounds)
UICollectionViewLayoutInvalidationContext	invalidationContextForEndingInteractiveMovementOfItemsToFinalIndexPathsPreviousIndexPathsMovementCancelled(NSArray<? extends NSIndexPath> indexPaths, NSArray<? extends NSIndexPath> previousIndexPaths, boolean movementCancelled)
UICollectionViewLayoutInvalidationContext	invalidationContextForInteractivelyMovingItemsWithTargetPositionPreviousIndexPathsPreviousPosition(NSArray<? extends NSIndexPath> targetIndexPaths, CGPoint targetPosition, NSArray<? extends NSIndexPath> previousIndexPaths, CGPoint previousPosition)
UICollectionViewLayoutInvalidationContext	invalidationContextForPreferredLayoutAttributesWithOriginalAttributes(UICollectionViewLayoutAttributes preferredAttributes, UICollectionViewLayoutAttributes originalAttributes)
static boolean	isSubclassOfClass(org.moe.natj.objc.Class aClass)
static NSSet<java.lang.String>	keyPathsForValuesAffectingValueForKey(java.lang.String key)
static org.moe.natj.objc.Class	layoutAttributesClass() override this method to provide a custom class to be used when instantiating instances of UICollectionViewLayoutAttributes
UICollectionViewLayoutAttributes	layoutAttributesForDecorationViewOfKindAtIndexPath(java.lang.String elementKind, NSIndexPath indexPath)
NSArray<? extends UICollectionViewLayoutAttributes>	layoutAttributesForElementsInRect(CGRect rect) return an array layout attributes instances for all the views in the given rect
UICollectionViewLayoutAttributes	layoutAttributesForInteractivelyMovingItemAtIndexPathWithTargetPosition(NSIndexPath indexPath, CGPoint position)
UICollectionViewLayoutAttributes	layoutAttributesForItemAtIndexPath(NSIndexPath indexPath)
UICollectionViewLayoutAttributes	layoutAttributesForSupplementaryViewOfKindAtIndexPath(java.lang.String elementKind, NSIndexPath indexPath)
static UICollectionViewLayout	new_objc()
void	prepareForAnimatedBoundsChange(CGRect oldBounds) UICollectionView calls this when its bounds have changed inside an animation block before displaying cells in its new bounds
void	prepareForCollectionViewUpdates(NSArray<? extends UICollectionViewUpdateItem> updateItems) This method is called when there is an update with deletes/inserts to the collection view.
void	prepareForTransitionFromLayout(UICollectionViewLayout oldLayout)
void	prepareForTransitionToLayout(UICollectionViewLayout newLayout) UICollectionView calls this when prior the layout transition animation on the incoming and outgoing layout
void	prepareLayout() The collection view calls -prepareLayout once at its first layout as the first message to the layout instance.
void	registerClassForDecorationViewOfKind(org.moe.natj.objc.Class viewClass, java.lang.String elementKind)
void	registerNibForDecorationViewOfKind(UINib nib, java.lang.String elementKind)
static boolean	resolveClassMethod(org.moe.natj.objc.SEL sel)
static boolean	resolveInstanceMethod(org.moe.natj.objc.SEL sel)
static void	setVersion_static(long aVersion)
boolean	shouldInvalidateLayoutForBoundsChange(CGRect newBounds) return YES to cause the collection view to requery the layout for geometry information
boolean	shouldInvalidateLayoutForPreferredLayoutAttributesWithOriginalAttributes(UICollectionViewLayoutAttributes preferredAttributes, UICollectionViewLayoutAttributes originalAttributes)
static org.moe.natj.objc.Class	superclass_static()
CGPoint	targetContentOffsetForProposedContentOffset(CGPoint proposedContentOffset) a layout can return the content offset to be applied during transition or update animations
CGPoint	targetContentOffsetForProposedContentOffsetWithScrollingVelocity(CGPoint proposedContentOffset, CGPoint velocity) return a point at which to rest after scrolling - for layouts that want snap-to-point scrolling behavior
NSIndexPath	targetIndexPathForInteractivelyMovingItemWithPosition(NSIndexPath previousIndexPath, CGPoint position)
static long	version_static()

Methods inherited from class apple.NSObject

accessibilityActivate, accessibilityActivationPoint, accessibilityAssistiveTechnologyFocusedIdentifiers, accessibilityAttributedHint, accessibilityAttributedLabel, accessibilityAttributedUserInputLabels, accessibilityAttributedValue, accessibilityContainerType, accessibilityCustomActions, accessibilityCustomRotors, accessibilityDecrement, accessibilityDragSourceDescriptors, accessibilityDropPointDescriptors, accessibilityElementAtIndex, accessibilityElementCount, accessibilityElementDidBecomeFocused, accessibilityElementDidLoseFocus, accessibilityElementIsFocused, accessibilityElements, accessibilityElementsHidden, accessibilityFrame, accessibilityHint, accessibilityIncrement, accessibilityLabel, accessibilityLanguage, accessibilityNavigationStyle, accessibilityPath, accessibilityPerformEscape, accessibilityPerformMagicTap, accessibilityRespondsToUserInteraction, accessibilityScroll, accessibilityTextualContext, accessibilityTraits, accessibilityUserInputLabels, accessibilityValue, accessibilityViewIsModal, addObserverForKeyPathOptionsContext, attemptRecoveryFromErrorOptionIndex, attemptRecoveryFromErrorOptionIndexDelegateDidRecoverSelectorContextInfo, autoContentAccessingProxy, awakeAfterUsingCoder, awakeFromNib, class_objc, classForCoder, classForKeyedArchiver, copy, dealloc, debugDescription, description, dictionaryWithValuesForKeys, didChangeValueForKey, didChangeValueForKeyWithSetMutationUsingObjects, didChangeValuesAtIndexesForKey, doesNotRecognizeSelector, fileManagerShouldProceedAfterError, fileManagerWillProcessPath, finalize_objc, forwardingTargetForSelector, forwardInvocation, hash, indexOfAccessibilityElement, isAccessibilityElement, isEqual, isKindOfClass, isMemberOfClass, isProxy, methodForSelector, methodSignatureForSelector, mutableArrayValueForKey, mutableArrayValueForKeyPath, mutableCopy, mutableOrderedSetValueForKey, mutableOrderedSetValueForKeyPath, mutableSetValueForKey, mutableSetValueForKeyPath, observationInfo, observeValueForKeyPathOfObjectChangeContext, performSelector, performSelectorInBackgroundWithObject, performSelectorOnMainThreadWithObjectWaitUntilDone, performSelectorOnMainThreadWithObjectWaitUntilDoneModes, performSelectorOnThreadWithObjectWaitUntilDone, performSelectorOnThreadWithObjectWaitUntilDoneModes, performSelectorWithObject, performSelectorWithObjectAfterDelay, performSelectorWithObjectAfterDelayInModes, performSelectorWithObjectWithObject, prepareForInterfaceBuilder, provideImageDataBytesPerRowOrigin_Size_UserInfo, removeObserverForKeyPath, removeObserverForKeyPathContext, replacementObjectForCoder, replacementObjectForKeyedArchiver, respondsToSelector, self, setAccessibilityActivationPoint, setAccessibilityAttributedHint, setAccessibilityAttributedLabel, setAccessibilityAttributedUserInputLabels, setAccessibilityAttributedValue, setAccessibilityContainerType, setAccessibilityCustomActions, setAccessibilityCustomRotors, setAccessibilityDragSourceDescriptors, setAccessibilityDropPointDescriptors, setAccessibilityElements, setAccessibilityElementsHidden, setAccessibilityFrame, setAccessibilityHint, setAccessibilityLabel, setAccessibilityLanguage, setAccessibilityNavigationStyle, setAccessibilityPath, setAccessibilityRespondsToUserInteraction, setAccessibilityTextualContext, setAccessibilityTraits, setAccessibilityUserInputLabels, setAccessibilityValue, setAccessibilityViewIsModal, setIsAccessibilityElement, setNilValueForKey, setObservationInfo, setShouldGroupAccessibilityChildren, setValueForKey, setValueForKeyPath, setValueForUndefinedKey, setValuesForKeysWithDictionary, shouldGroupAccessibilityChildren, superclass, validateValueForKeyError, validateValueForKeyPathError, valueForKey, valueForKeyPath, valueForUndefinedKey, willChangeValueForKey, willChangeValueForKeyWithSetMutationUsingObjects, willChangeValuesAtIndexesForKey

Methods inherited from class org.moe.natj.objc.ObjCObject

equals, toString

Methods inherited from class org.moe.natj.general.NativeObject

finalize, getPeer, getPeerPointer

Methods inherited from class java.lang.Object

clone, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

UICollectionViewLayout

protected UICollectionViewLayout(org.moe.natj.general.Pointer peer)

Method Detail

accessInstanceVariablesDirectly

public static boolean accessInstanceVariablesDirectly()

alloc

public static UICollectionViewLayout alloc()

allocWithZone

public static UICollectionViewLayout allocWithZone(org.moe.natj.general.ptr.VoidPtr zone)

automaticallyNotifiesObserversForKey

public static boolean automaticallyNotifiesObserversForKey(java.lang.String key)

cancelPreviousPerformRequestsWithTarget

public static void cancelPreviousPerformRequestsWithTarget(java.lang.Object aTarget)

cancelPreviousPerformRequestsWithTargetSelectorObject

public static void cancelPreviousPerformRequestsWithTargetSelectorObject(java.lang.Object aTarget,
                                                                         org.moe.natj.objc.SEL aSelector,
                                                                         java.lang.Object anArgument)

classFallbacksForKeyedArchiver

public static NSArray<java.lang.String> classFallbacksForKeyedArchiver()

classForKeyedUnarchiver

public static org.moe.natj.objc.Class classForKeyedUnarchiver()

debugDescription_static

public static java.lang.String debugDescription_static()

description_static

public static java.lang.String description_static()

hash_static

public static long hash_static()

instanceMethodForSelector

public static NSObject.Function_instanceMethodForSelector_ret instanceMethodForSelector(org.moe.natj.objc.SEL aSelector)

instanceMethodSignatureForSelector

public static NSMethodSignature instanceMethodSignatureForSelector(org.moe.natj.objc.SEL aSelector)

instancesRespondToSelector

public static boolean instancesRespondToSelector(org.moe.natj.objc.SEL aSelector)

invalidationContextClass

public static org.moe.natj.objc.Class invalidationContextClass()

override this method to provide a custom class to be used for invalidation contexts

isSubclassOfClass

public static boolean isSubclassOfClass(org.moe.natj.objc.Class aClass)

keyPathsForValuesAffectingValueForKey

public static NSSet<java.lang.String> keyPathsForValuesAffectingValueForKey(java.lang.String key)

layoutAttributesClass

public static org.moe.natj.objc.Class layoutAttributesClass()

override this method to provide a custom class to be used when instantiating instances of UICollectionViewLayoutAttributes

new_objc

public static UICollectionViewLayout new_objc()

resolveClassMethod

public static boolean resolveClassMethod(org.moe.natj.objc.SEL sel)

resolveInstanceMethod

public static boolean resolveInstanceMethod(org.moe.natj.objc.SEL sel)

setVersion_static

public static void setVersion_static(long aVersion)

superclass_static

public static org.moe.natj.objc.Class superclass_static()

version_static

public static long version_static()

collectionView

public UICollectionView collectionView()

Methods in this class are meant to be overridden and will be called by its collection view to gather layout information. To get the truth on the current state of the collection view, call methods on UICollectionView rather than these.

collectionViewContentSize

public CGSize collectionViewContentSize()

Subclasses must override this method and use it to return the width and height of the collection view’s content. These values represent the width and height of all the content, not just the content that is currently visible. The collection view uses this information to configure its own content size to facilitate scrolling.

encodeWithCoder

public void encodeWithCoder(NSCoder coder)

Specified by:

encodeWithCoder in interface NSCoding

finalLayoutAttributesForDisappearingDecorationElementOfKindAtIndexPath

public UICollectionViewLayoutAttributes finalLayoutAttributesForDisappearingDecorationElementOfKindAtIndexPath(java.lang.String elementKind,
                                                                                                               NSIndexPath decorationIndexPath)

finalLayoutAttributesForDisappearingItemAtIndexPath

public UICollectionViewLayoutAttributes finalLayoutAttributesForDisappearingItemAtIndexPath(NSIndexPath itemIndexPath)

finalLayoutAttributesForDisappearingSupplementaryElementOfKindAtIndexPath

public UICollectionViewLayoutAttributes finalLayoutAttributesForDisappearingSupplementaryElementOfKindAtIndexPath(java.lang.String elementKind,
                                                                                                                  NSIndexPath elementIndexPath)

finalizeAnimatedBoundsChange

public void finalizeAnimatedBoundsChange()

also called inside the animation block

finalizeCollectionViewUpdates

public void finalizeCollectionViewUpdates()

called inside an animation block after the update

finalizeLayoutTransition

public void finalizeLayoutTransition()

called inside an animation block after the transition

indexPathsToDeleteForDecorationViewOfKind

public NSArray<? extends NSIndexPath> indexPathsToDeleteForDecorationViewOfKind(java.lang.String elementKind)

indexPathsToDeleteForSupplementaryViewOfKind

public NSArray<? extends NSIndexPath> indexPathsToDeleteForSupplementaryViewOfKind(java.lang.String elementKind)

These methods are called by collection view during an update block. Return an array of index paths to indicate views that the layout is deleting or inserting in response to the update.

indexPathsToInsertForDecorationViewOfKind

public NSArray<? extends NSIndexPath> indexPathsToInsertForDecorationViewOfKind(java.lang.String elementKind)

indexPathsToInsertForSupplementaryViewOfKind

public NSArray<? extends NSIndexPath> indexPathsToInsertForSupplementaryViewOfKind(java.lang.String elementKind)

init

public UICollectionViewLayout init()

Overrides:

init in class NSObject

initWithCoder

public UICollectionViewLayout initWithCoder(NSCoder coder)

Description copied from interface: NSCoding

NS_DESIGNATED_INITIALIZER

Specified by:

initWithCoder in interface NSCoding

initialLayoutAttributesForAppearingDecorationElementOfKindAtIndexPath

public UICollectionViewLayoutAttributes initialLayoutAttributesForAppearingDecorationElementOfKindAtIndexPath(java.lang.String elementKind,
                                                                                                              NSIndexPath decorationIndexPath)

initialLayoutAttributesForAppearingItemAtIndexPath

public UICollectionViewLayoutAttributes initialLayoutAttributesForAppearingItemAtIndexPath(NSIndexPath itemIndexPath)

This set of methods is called when the collection view undergoes an animated transition such as a batch update block or an animated bounds change. For each element on screen before the invalidation, finalLayoutAttributesForDisappearingXXX will be called and an animation setup from what is on screen to those final attributes. For each element on screen after the invalidation, initialLayoutAttributesForAppearingXXX will be called and an animation setup from those initial attributes to what ends up on screen.

initialLayoutAttributesForAppearingSupplementaryElementOfKindAtIndexPath

public UICollectionViewLayoutAttributes initialLayoutAttributesForAppearingSupplementaryElementOfKindAtIndexPath(java.lang.String elementKind,
                                                                                                                 NSIndexPath elementIndexPath)

invalidateLayout

public void invalidateLayout()

Call -invalidateLayout to indicate that the collection view needs to requery the layout information. Subclasses must always call super if they override.

invalidateLayoutWithContext

public void invalidateLayoutWithContext(UICollectionViewLayoutInvalidationContext context)

invalidationContextForBoundsChange

public UICollectionViewLayoutInvalidationContext invalidationContextForBoundsChange(CGRect newBounds)

invalidationContextForEndingInteractiveMovementOfItemsToFinalIndexPathsPreviousIndexPathsMovementCancelled

public UICollectionViewLayoutInvalidationContext invalidationContextForEndingInteractiveMovementOfItemsToFinalIndexPathsPreviousIndexPathsMovementCancelled(NSArray<? extends NSIndexPath> indexPaths,
                                                                                                                                                            NSArray<? extends NSIndexPath> previousIndexPaths,
                                                                                                                                                            boolean movementCancelled)

invalidationContextForInteractivelyMovingItemsWithTargetPositionPreviousIndexPathsPreviousPosition

public UICollectionViewLayoutInvalidationContext invalidationContextForInteractivelyMovingItemsWithTargetPositionPreviousIndexPathsPreviousPosition(NSArray<? extends NSIndexPath> targetIndexPaths,
                                                                                                                                                    CGPoint targetPosition,
                                                                                                                                                    NSArray<? extends NSIndexPath> previousIndexPaths,
                                                                                                                                                    CGPoint previousPosition)

invalidationContextForPreferredLayoutAttributesWithOriginalAttributes

public UICollectionViewLayoutInvalidationContext invalidationContextForPreferredLayoutAttributesWithOriginalAttributes(UICollectionViewLayoutAttributes preferredAttributes,
                                                                                                                       UICollectionViewLayoutAttributes originalAttributes)

layoutAttributesForDecorationViewOfKindAtIndexPath

public UICollectionViewLayoutAttributes layoutAttributesForDecorationViewOfKindAtIndexPath(java.lang.String elementKind,
                                                                                           NSIndexPath indexPath)

layoutAttributesForElementsInRect

public NSArray<? extends UICollectionViewLayoutAttributes> layoutAttributesForElementsInRect(CGRect rect)

return an array layout attributes instances for all the views in the given rect

layoutAttributesForInteractivelyMovingItemAtIndexPathWithTargetPosition

public UICollectionViewLayoutAttributes layoutAttributesForInteractivelyMovingItemAtIndexPathWithTargetPosition(NSIndexPath indexPath,
                                                                                                                CGPoint position)

layoutAttributesForItemAtIndexPath

public UICollectionViewLayoutAttributes layoutAttributesForItemAtIndexPath(NSIndexPath indexPath)

layoutAttributesForSupplementaryViewOfKindAtIndexPath

public UICollectionViewLayoutAttributes layoutAttributesForSupplementaryViewOfKindAtIndexPath(java.lang.String elementKind,
                                                                                              NSIndexPath indexPath)

prepareForAnimatedBoundsChange

public void prepareForAnimatedBoundsChange(CGRect oldBounds)

UICollectionView calls this when its bounds have changed inside an animation block before displaying cells in its new bounds

prepareForCollectionViewUpdates

public void prepareForCollectionViewUpdates(NSArray<? extends UICollectionViewUpdateItem> updateItems)

This method is called when there is an update with deletes/inserts to the collection view. It will be called prior to calling the initial/final layout attribute methods below to give the layout an opportunity to do batch computations for the insertion and deletion layout attributes. The updateItems parameter is an array of UICollectionViewUpdateItem instances for each element that is moving to a new index path.

prepareForTransitionFromLayout

public void prepareForTransitionFromLayout(UICollectionViewLayout oldLayout)

prepareForTransitionToLayout

public void prepareForTransitionToLayout(UICollectionViewLayout newLayout)

UICollectionView calls this when prior the layout transition animation on the incoming and outgoing layout

prepareLayout

public void prepareLayout()

The collection view calls -prepareLayout once at its first layout as the first message to the layout instance. The collection view calls -prepareLayout again after layout is invalidated and before requerying the layout information. Subclasses should always call super if they override.

registerClassForDecorationViewOfKind

public void registerClassForDecorationViewOfKind(org.moe.natj.objc.Class viewClass,
                                                 java.lang.String elementKind)

registerNibForDecorationViewOfKind

public void registerNibForDecorationViewOfKind(UINib nib,
                                               java.lang.String elementKind)

shouldInvalidateLayoutForBoundsChange

public boolean shouldInvalidateLayoutForBoundsChange(CGRect newBounds)

return YES to cause the collection view to requery the layout for geometry information

shouldInvalidateLayoutForPreferredLayoutAttributesWithOriginalAttributes

public boolean shouldInvalidateLayoutForPreferredLayoutAttributesWithOriginalAttributes(UICollectionViewLayoutAttributes preferredAttributes,
                                                                                        UICollectionViewLayoutAttributes originalAttributes)

targetContentOffsetForProposedContentOffset

public CGPoint targetContentOffsetForProposedContentOffset(CGPoint proposedContentOffset)

a layout can return the content offset to be applied during transition or update animations

targetContentOffsetForProposedContentOffsetWithScrollingVelocity

public CGPoint targetContentOffsetForProposedContentOffsetWithScrollingVelocity(CGPoint proposedContentOffset,
                                                                                CGPoint velocity)

return a point at which to rest after scrolling - for layouts that want snap-to-point scrolling behavior

targetIndexPathForInteractivelyMovingItemWithPosition

public NSIndexPath targetIndexPathForInteractivelyMovingItemWithPosition(NSIndexPath previousIndexPath,
                                                                         CGPoint position)

developmentLayoutDirection

public long developmentLayoutDirection()

Default implementation returns the layout direction of the main bundle's development region; FlowLayout returns leftToRight. Subclasses may override this to specify the implementation-time layout direction of the layout.

flipsHorizontallyInOppositeLayoutDirection

public boolean flipsHorizontallyInOppositeLayoutDirection()

Base implementation returns false. If your subclass’s implementation overrides this property to return true, a UICollectionView showing this layout will ensure its bounds.origin is always found at the leading edge, flipping its coordinate system horizontally if necessary.