iOS 6 introduced a new feature called UICollectionView. UICollectionViewWaterfallLayout is a subclass of UICollectionViewLayout.

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

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

Read the demo codes for detail information.

There are four properties for you to set up.

@property (nonatomic, weak) id<UICollectionViewDelegateWaterfallLayout> delegate;
@property (nonatomic, assign) NSUInteger columnCount; // How many columns
@property (nonatomic, assign) CGFloat itemWidth; // Width for every column
@property (nonatomic, assign) UIEdgeInsets sectionInset; // The margins used to lay out content in a section

It's your responsibility to set up delegate, columnCount, and itemWidth, they are required. But sectionInset is optional.

And you also need to implement one method in your delegate for the UICollectionViewDelegateWaterfallLayout protocol.

- (CGFloat)collectionView:(UICollectionView *)collectionView
                   layout:(UICollectionViewWaterfallLayout *)collectionViewLayout
 heightForItemAtIndexPath:(NSIndexPath *)indexPath;

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

Quoted from PSTUICollectionView 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)

That's all! Easy, right?

• Only one section is supported.
• Only vertical scrolling is supported.
• No supplementary view and decoration view.

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

None, so far.