xcode UICollectionView 顶部和侧面的浮动标题
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UICollectionView Floating Headers on Top and Side
提问by Mason Wolters
How do you implement headers in a UICollectionView? I know you can put in supplementary views, but I don't know how to make them "float" above a section like headers in a UITableViewdo.
你如何在 a 中实现标题UICollectionView？我知道你可以添加补充视图，但我不知道如何让它们像标题一样“浮动”在一个部分之上UITableView。
Here's my situation: I have a collectionViewwith the cells laid out in a grid format. You can scroll horizontally and vertically. I want to have a header on top so that when you scroll horizontally it scrolls horizontally with it, but it doesn't scroll vertically. I also want the same sort of thing on the left side where it scrolls vertically with the collectionViewbut not horizontally. Is implementing this with supplementary views the right approach?
这是我的情况：我有一个collectionView以网格格式布置的单元格。您可以水平和垂直滚动。我想在顶部有一个标题，这样当您水平滚动时，它会随之水平滚动，但不会垂直滚动。我也想在左侧使用相同的东西，它可以垂直滚动collectionView但不是水平滚动。用补充意见来实现这一点是正确的方法吗？
The final functionality I am looking for is similar to that of the Numbers spreadsheet app on iOS.
我正在寻找的最终功能类似于 iOS 上的 Numbers 电子表格应用程序。
Thanks in advance for your help!
在此先感谢您的帮助！
回答by AMayes
Update for iOS9:
iOS9 更新：
let flow = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
flow.sectionHeadersPinToVisibleBounds = true
Pass it along.
传过去。
回答by Audun Kjelstrup
EDIT: As mentioned in the comments, this answer is valid, but not for multiple sections. See this blog for a better solution: http://blog.radi.ws/post/32905838158/sticky-headers-for-uicollectionview-using#notes
编辑：如评论中所述，此答案有效，但不适用于多个部分。请参阅此博客以获得更好的解决方案：http: //blog.radi.ws/post/32905838158/sticky-headers-for-uicollectionview-using#notes
You need to specify that behaviour in your layout:
您需要在布局中指定该行为：
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
NSMutableArray* attributesArray = [[super layoutAttributesForElementsInRect:rect] mutableCopy];
BOOL headerVisible = NO;
for (UICollectionViewLayoutAttributes *attributes in attributesArray) {
if ([attributes.representedElementKind isEqualToString:UICollectionElementKindSectionHeader]) {
headerVisible = YES;
attributes.frame = CGRectMake(self.collectionView.contentOffset.x, 0, self.headerReferenceSize.width, self.headerReferenceSize.height);
attributes.alpha = HEADER_ALPHA;
attributes.zIndex = 2;
}
}
if (!headerVisible) {
UICollectionViewLayoutAttributes *attributes = [self layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionHeader
atIndexPath:[NSIndexPath
indexPathForItem:0
inSection:0]];
[attributesArray addObject:attributes];
}
return attributesArray;
}
