UICollectionViewFlexLayout

UICollectionViewFlexLayout is a drop-in replacement for UICollectionViewFlowLayout.

Features

• Section Spacing
• Section Margin
• Section Padding
• Section Background
• Item Spacing
• Item Margin
• Item Padding
• Item Size
• Item Background
• Item Z-Index

Basic Concept

Don’t let cells have margins and paddings. Cell metrics are now set outside of the cell. Just focus on contents.

Usage

UICollectionViewDelegateFlexLayout

protocol UICollectionViewDelegateFlexLayout {
  // section vertical spacing
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, verticalSpacingBetweenSectionAt section: Int, and nextSection: Int) -> CGFloat

  // section margin
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, marginForSectionAt section: Int) -> UIEdgeInsets

  // section padding
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, paddingForSectionAt section: Int) -> UIEdgeInsets

  // item horizontal spacing
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, horizontalSpacingBetweenItemAt indexPath: IndexPath, and nextIndexPath: IndexPath) -> CGFloat

  // item vertical spacing
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, verticalSpacingBetweenItemAt indexPath: IndexPath, and nextIndexPath: IndexPath) -> CGFloat

  // item margin
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, marginForItemAt indexPath: IndexPath) -> UIEdgeInsets

  // item padding
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, paddingForItemAt indexPath: IndexPath) -> UIEdgeInsets

  // item size
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, sizeForItemAt indexPath: IndexPath) -> CGSize

  // item z-index
  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlexLayout, zIndexForItemAt indexPath: IndexPath) -> Int
}

Section and Item Background

// register
collectionView.register(MySectionBackgroundView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionBackground, withReuseIdentifier: "mySectionBackgroundView")
collectionView.register(MyItemBackgroundView.self, forSupplementaryViewOfKind: UICollectionElementKindItemBackground, withReuseIdentifier: "myItemBackgroundView")

// configure
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
  switch kind {
  case UICollectionElementKindSectionBackground: // section background
    return collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionBackground, withReuseIdentifier: "mySectionBackgroundView", for: indexPath)

  case UICollectionElementKindItemBackground: // item background
    return collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindItemBackground, withReuseIdentifier: "myItemBackgroundView", for: indexPath)

  case foo: // else
    return bar
  }
}

Tips and Tricks

• Using with RxCocoa

  If you’re using UICollectionView with RxSwift and RxCocoa, you should create an extension of _RXDelegateProxy class to support delegate proxy.

  import RxCocoa
  import UICollectionViewFlexLayout
  
  extension _RXDelegateProxy: UICollectionViewDelegateFlexLayout {
  }

Contributing

$ swift package generate-xcodeproj

License

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