0414--iOS之UICollectionViewFlowLayoutInvalidationContext类

Class

UICollectionViewFlowLayoutInvalidationContext

A set of properties for determining whether to recompute the size of items or their position in the layout.

         --一组属性，用于确定是否需要重新计算items的大小或items在布局中的位置。
 

Declaration

class UICollectionViewFlowLayoutInvalidationContext : UICollectionViewLayoutInvalidationContext

         --继承于UICollectionViewLayoutInvalidationContex

Overview         --概览

The flow layout object creates instances of this class when it needs to invalidate its contents in response to changes. You can also create instances when invalidating the flow layout manually.

         --flow layout对象在“因为布局变化而需要无效化内容时”创建此类的实例。也可以在“手动无效化流布局时”创建实例

 

Topics             --专题

Specifying What to Invalidate               --指定什么需要被无效化

var invalidateFlowLayoutDelegateMetrics: Bool      --是否需要无效化items和view的尺寸

A Boolean indicating whether to recompute the size of items and views in the layout.       

var invalidateFlowLayoutAttributes: Bool      --是否需要重新计算布局中items和view的布局特征

A Boolean indicating whether to recompute the layout attributes for items and views in the layout.

 

Relationships

Inherits From

UICollectionViewLayoutInvalidationContext

Conforms To

• CVarArg

  , 

• Equatable

  , 

• Hashable

See Also

Layout Updates

class UICollectionViewUpdateItem

An object that describes a single change to make to an item in a collection view.

class UICollectionViewFocusUpdateContext

A context object that stores information specific to a focus update in a collection view.

class UICollectionViewLayoutInvalidationContext

A context object that declares which parts of your layout need to be updated when the layout is invalidated.