CHTCollectionViewWaterfallLayout

CHTCollectionViewWaterfallLayout is a subclass of UICollectionViewLayout, and it trys to imitate UICollectionViewFlowLayout's usage as much as possible.

This layout is inspired by Pinterest. It also is compatible with PSTCollectionView.

Screen Shots

Prerequisite

ARC
Xcode 4.4+, which supports literals syntax.
iOS 6+, or
iOS 4.x/5.x, with PSTCollectionView.

How to Use

Read the demo codes and CHTCollectionViewWaterfallLayout.h header file for more information.

Step 1

There are some properties for you. Although they have default values, I strongly recommand you to set up columnCount to suit your needs.

@property (nonatomic, assign) NSInteger columnCount;
@property (nonatomic, assign) CGFloat minimumColumnSpacing;
@property (nonatomic, assign) CGFloat minimumInteritemSpacing;
@property (nonatomic, assign) CGFloat headerHeight;
@property (nonatomic, assign) CGFloat footerHeight;
@property (nonatomic, assign) UIEdgeInsets sectionInset;

Step 2

Your collectionView's delegate (which often is your view controller) must conforms to CHTCollectionViewDelegateWaterfallLayout protocol and implements the required method:

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath;

Step 3 (Optional)

If you need to support iOS 4.x/5.x and you have installed PSTCollectionView, then you NEED to modify some codes.

Quoted from PSTCollectionView README file:

If you want to have PSTCollectionView on iOS4.3/5.x and UICollectionView on iOS6, use PSUICollectionView (basically add PS on any UICollectionView class to get auto-support for older iOS versions)* If you always want to use PSTCollectionView, use PSTCollectionView as class names. (replace the UI with PST)

Limitation

Only vertical scrolling is supported.
No decoration view.

License

CHTCollectionViewWaterfallLayout is available under the MIT license. See the LICENSE file for more info.

Changelog

0.0.6

[Add] Add minimumColumnSpacing and minimumInteritemSpacing properties.
[Remove] Remove itemWidth property. The layout object will calculate a proper item width automatically.
[Change] Rename delegate method - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout heightForItemAtIndexPath:(NSIndexPath *)indexPath to - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath. It should return original size for each item.
[Fix] Section header and/or footer should work properly.
[Fix] Use sectionInset correctly.

0.0.5

[Add] Multiple sections.
[Add] Header and/or footer for section.
[Add] More properties and delegation methods.
[Change] Remove delegate property, your collectionView's delegate MUST conforms to <CHTCollectionViewDelegateWaterfallLayout> protocol.

lisafiedler / CHTCollectionViewWaterfallLayout