UICollectionView 上的装饰视图在每次插入时都重复 [英] DecorationViews on UICollectionView are duplicated on every insert

问题描述

我正在尝试使用 UICollectionView 创建书架，与 iBooks 应用程序不同.

它工作得很好，但是每当我插入一个新项目到视图中(通过调用insertItemsAtIndexPaths:)，该项目被正确插入，但我的货架项目(是 DecorationViews，UICollectionReusableView 的子类越来越暗，显然被一遍又一遍地绘制.但是，如果在 UICollectionView 上调用 reloadData，一切都会正确绘制.

这是我在派生的 UICollectionViewFlowLayout 类中所做的:

• - (void)prepareLayout 计算框架装饰视图

• - (NSArray *)layoutAttributesForElementsInRect: 添加UICollectionViewLayoutAttributes 用于所有与正则

• - (UICollectionViewLayoutAttributes*)layoutAttributesForItemAtIndexPath:(NSIndexPath *) 将我的项目属性的 zIndex 调整为 1

• - (UICollectionViewLayoutAttributes*)layoutAttributesForDecorationViewOfKind:(NSString *) atIndexPath:(NSIndexPath *) 为我的书架调整 zIndex属性为 0

就是这样.我错过了什么吗?

解决方案

听起来像(另一个)装饰视图的错误.我提交了一个错误，当设备旋转时它们会重复.>

I am trying to create a book shelf with an UICollectionView, not unlike the iBooks app.

It works nicely, however whenever I insert a new item into the view (by calling insertItemsAtIndexPaths:), the item is inserted correctly, but my shelf items (which are DecorationViews, subclasses of UICollectionReusableView) are getting darker and darker, obviously being painted over and over again. However, if a call reloadData on the UICollectionView everything is painted correct.

This is what I did in my derived UICollectionViewFlowLayout class:

• - (void)prepareLayout Calculating the frames for the DecorationViews

• - (NSArray *)layoutAttributesForElementsInRect: Adding UICollectionViewLayoutAttributes for all shelves which intersect the rect

• - (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *) Adjusting zIndex for my item attributes to 1

• - (UICollectionViewLayoutAttributes *)layoutAttributesForDecorationViewOfKind:(NSString *) atIndexPath:(NSIndexPath *) Adjusting zIndex for my shelf attributes to 0

That's it. Did I miss something?

解决方案

Sounds like (another) bug with decoration views. I've filed a bug that they're duplicated when the device is rotated.

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