How did you resolve this ins swift 3 ?

let yOffset = ((self.columnHeights[section] as AnyObject).object(columnIndex) as AnyObject).doubleValue

gives me error 'Cannot call value of non-function type 'Any?!''

(self.columnHeights[section] as AnyObject).enumerateObjects({(object : AnyObject!, idx : NSInteger,pointer :UnsafeMutablePointer) and this one gives error ' Cannot invoke 'enumerateObjects' with an argument list of type '((AnyObject!, NSInteger, UnsafeMutablePointer) -> ())';

I used Xcode 8 converter and this is the result, thx for help

First off, great work on the layout. I use the layout for a couple sections with three or four items each. Each section has a header and the items are populated by data retrieved from a network call. I have a method that removes all objects from the data source and sets everything back to zero. For example, 0 sections, with 0 items. Essentially an empty array. The method looks a bit like this:

- (IBAction)resetButtonTapped:(id)sender
{
    [self.dataSource removeAllObjects];
    [self.collectionView reloadData];
}

Whenever I reset everything back to zero, and call reloadData, the following exception is thrown:

*** Assertion failure in -[UICollectionViewData layoutAttributesForSupplementaryElementOfKind:atIndexPath:], /SourceCache/UIKit_Sim/UIKit-3318/UICollectionViewData.m:853
2014-10-19 19:18:22.554 Hord[31192:4215382] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'request for layout attributes for supplementary view CHTCollectionElementKindSectionHeader in section 0 when there are only 0 sections in the collection view'

A similar issue was reported on another custom UICollectionViewLayout here. However, the other layout appears to have some sort of cache invalidation logic built in.

It looks like the layout object is still trying to return attributes for a header that no longer exists. Any advice you have on resolving this issue is much appreciated. Thanks in advance!

This function is spending a considerable amount of time calculating the layoutAttributes during scrolling which lowers the frame rate significantly :(

#166 @rafaelcr @chiahsien

I find header attributed AND footer attributed THED merge return attributed

so . header and footer KEY == [NSIndexPath indexPathForItem:0 inSection:section]

The result is that the footer will MUST replace the header

@chiahsien We were having issues with the frame vs. bounds values when we rotated the view to support horizontal scrolling (admittedly, I've been meaning to look into adding this support, but we were in a time crunch :) ), and iOS sometimes has a discrepancy between frame and bounds values when adjusting the transform of a view. Let me know if you have any concerns here!

I am using your layout (fantastic job) however I seem to run into an issue where I want to set the height for the header at runtime. However all your examples show a static size. Is it possible to configure height dynamically at runtime?

publicHeadersPath is relative to the path parameter. Without this change, no headers are exposed for consuming libraries and apps to use. I tested this in a sample project to verify. We may want to consider adding demo apps for the two swift package libraries to ensure this can't happen again.

I try to import CHTCollectionViewWaterfallLayout using "pod update ", but I get error:

[!] The platform of the target Pods (iOS 5.0) is not compatible with CHTCollectionViewWaterfallLayout (0.0.1) which has a minimum requirement of iOS 6.0.

How should I do this right?

It's not possible to use it on iOS5. Several points:

• UICollectionViewDelegate and UICollectionViewLayout do not exist on iOS5
• When used with PSTCollectionView on iOS5 it raises an exception when PSTCollectionView tries to put itself in collectionView property of the layout.

The platform of the target `Fishbrain` (iOS 8.0) is not compatible with `CHTCollectionViewWaterfallLayout (0.9.3)`, which does not support `ios`.

Temporary solution was to rollback to old version:

Lock CHTCollectionViewWaterfallLayout to 0.9.2 in PodsLocal/FIBCollectionViewController/FIBCollectionViewController.podspec.json

The cards that are being rendered are not in the order of my data array. For eg.: . _ _ _ _ _ . | |1| |2| |3| | | |5| |6| |4| | | |8| |9| |7| | |_ _ _ _ _ .|

(apologies for the poor ASCII)

Do I have to set any property to fix this? I was expecting them to render left-right in each row:

1 2 3 4 5 6 7 8 9 ...

I realized that the SWIFT and ObjC packages differ in cell height logic.

The SWIFT version will set the height of the cell no matter what and will set the width when it's bigger than 0, otherwise it will set it to 50% of the screen width.

On ObjC on the other hand it will only set the height if the width is also bigger than 0.

The logic in Swift is here and the logic in ObjC is here

Objective-C:

- (CGFloat)itemWidthInSectionAtIndex:(NSInteger)section {
  UIEdgeInsets sectionInset;
  if ([self.delegate respondsToSelector:@selector(collectionView:layout:insetForSectionAtIndex:)]) {
    sectionInset = [self.delegate collectionView:self.collectionView layout:self insetForSectionAtIndex:section];
  } else {
    sectionInset = self.sectionInset;
  }
  CGFloat width = self.collectionView.bounds.size.width - sectionInset.left - sectionInset.right;
  NSInteger columnCount = [self columnCountForSection:section];

  CGFloat columnSpacing = self.minimumColumnSpacing;
  if ([self.delegate respondsToSelector:@selector(collectionView:layout:minimumColumnSpacingForSectionAtIndex:)]) {
    columnSpacing = [self.delegate collectionView:self.collectionView layout:self minimumColumnSpacingForSectionAtIndex:section];
  }

  return CHTFloorCGFloat((width - (columnCount - 1) * columnSpacing) / columnCount);
}

Swift:

    public func itemWidth(inSection section: Int) -> CGFloat {
        let columnCount = self.columnCount(forSection: section)
        let spaceColumCount = CGFloat(columnCount - 1)
        let width = collectionViewContentWidth(ofSection: section)
        return floor((width - (spaceColumCount * minimumColumnSpacing)) / CGFloat(columnCount))
    }

In Swift version, collectionView:layout:minimumColumnSpacingForSectionAtIndex not be called in real time. minimumColumnSpacing for section not work.

`extension BlogPostVC: CHTCollectionViewDelegateWaterfallLayout {

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { let width = (self.collectionView!.frame.width / 2 ) - 5 // create a cell size from the image size, and return the size if appStorage.userData?.userType == .admin && indexPath.row == 0 {

        return CGSize(width: width, height: 130)
    }
    else {
        
        return CGSize(width: width, height: 300) //blogs[indexPath.item].imageHeightFormatted
    }
}

//MARK: - CollectionView Waterfall Layout Delegate Methods (Required)

} `

Thread 1: "Attempted to scroll the collection view to an out-of-bounds item (0) when there are only 0 items in section 0. Collection view: <UICollectionView: 0x7fa1680a3600; frame = (0 0; 428 751); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x6000012ff210>; layer = <CALayer: 0x600001c1e420>; contentOffset: {0, 0}; contentSize: {428, 10}; adjustedContentInset: {0, 0, 44, 0}; layout: <CHTCollectionViewWaterfallLayout.CHTCollectionViewWaterfallLayout: 0x7fa165f25090>; dataSource: <HomeListController: 0x7fa165f24b00>>."

/* com.apple.ibtool.document.errors */ /Users/admin/Downloads/CHTCollectionViewWaterfallLayout-develop/Demo/Objective-C/Demo/en.lproj/MainStoryboard_iPhone.storyboard:global: error: Compiling IB documents for earlier than iOS 7 is no longer supported. [12]