quarezz / erjustifiedflowlayout

A subclass of UICollectionViewFlowLayout for iOS that supports different types of cell justification and inter-cell spacing.

ERJustifiedFlowLayout

[](https://travis-ci.org/Evan Roth/ERJustifiedFlowLayout)

About

This is for an iOS project and can be used on any iPad or iPhone. ERJustifiedFlowLayout is a subclass of Apple's UICollectionViewFlowLayout class, which is designed to be used in combination with a UICollectionView. This project assumes you are familiar with the latter—if not, you can read about UICollectionView here and you can read about UICollectionViewFlowLayout here.

ERJustifiedFlowLayout works with dynamic or static-sized UICollectionViewCells, as it only handles the layout aspect.

This project contains some code from the following sources: Michael Sand's answer to a question on SO and this Cocoanetics tutorial. Thanks for the inspiration!

Usage

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

Tested on iOS 7 and 8 on all iPads and iPhones from 4S to 6+.

Installation

ERJustifiedFlowLayout is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "ERJustifiedFlowLayout"

Instructions

ERJustifiedFlowLayout can be used programmatically in the viewDidLoad method of the view controller your collection view is in:

ERJustifiedFlowLayout *flowLayout = [[ERJustifiedFlowLayout alloc] init];

or a reference to it can be created from your xib/storyboard like so:

Once instantiated or referenced, ERJustifiedFlowLayout requires only the setting of one property, with a few others as options:

• Required: FlowLayoutHorizontalJustification—an enum on ERJustifiedFlowLayout that sets the type of horizontal justification to perform:
  • FlowLayoutHorizontalJustificationLeft
  • FlowLayoutHorizontalJustificationFull
  • FlowLayoutHorizontalJustificationRight
• Optional
  • horizontalCellPadding: controls the amount of absolute space between each cell. Default is 0. This property overrides the minimumInteritemSpacing property on UICollectionViewFlowLayout.
  • sectionInset: this UICollectionViewFlowLayout property can be set to provide left, right, top, and bottom section insets which are used in calculating cell justification.

Screenshots

This depicts the following settings:
FlowLayoutHorizontalJustificationLeft, left section inset = 20, horizontalCellPadding = 5

This depicts the following settings:
FlowLayoutHorizontalJustificationFull, left/right section inset = 20, horizontalCellPadding = 5

This depicts the following settings:
FlowLayoutHorizontalJustificationRight, right section inset = 20, horizontalCellPadding = 5

Improvements

Ability to vertically align cells (top, middle, bottom) is coming soon, as is the ability to horizontally center justify cells.

Author

Evan Roth, [email protected]

License

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