ChainPageCollectionView

A custom View with two level chained collection views and fancy transition animation.

Demo

Requirements

• iOS 9.0+
• Xcode 8

Installation

CocoaPods

Update your Podfile to include the following:

pod 'ChainPageCollectionView', '~> 1.0'

Run pod install.

NOTE: If you can not find the pod target. Please follow: https://stackoverflow.com/questions/31065447/no-such-module-when-i-use-cocoapods to build your pod target.

Usage

Basic Usage

import ChainPageCollectionView

1. Create ChainPageCollectionView

// chainView is this view controller's property.
chainView = ChainPageCollectionView(viewType: .normal)
chainView.delegate = self

2. Register cell for parentCollectionView and childCollectionView

chainView.parentCollectionView.register(#cellType, forCellWithReuseIdentifier:#cellIdentifier)
chainView.childCollectionView.register(#cellType, forCellWithReuseIdentifier:#cellIdentifier)

3. Implement ChainPageCollectionViewProtocol

func parentCollectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
  // return your parent data source count.
}

func parenCollectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
  // Dequeue and configure your parent collectionview cell
}

func childCollectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
  // return your child data source count.
}

func childCollectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
  // Dequeue and configure your child collectionview cell
}

4. Update child collection view data source when parent index has changed.

// You will get notified by following protocol method.
func childCollectionView(_ collectionView: UICollectionView, parentCollectionViewIndex: Int) {
  // When parent collection view's scroll stops, this will get called with new parent collectionview's index.
  // You can use this message to fetch related child collection view's new data.
  
  // Once you have the latest child collection view's data, set `childCollectionViewDataReady` to `true`.
  // NOTE: This is important to be set, otherwise your child collection view propably will not show up again.
  chainView.childCollectionViewDataReady = true
}

Customization

Child Collection View Animation Type

For now ChainPageCollectionView support two types of child collection view transition animation.

public enum ChainPageChildAnimationType {
  case slideOutSlideIn
  case shrinkOutExpandIn
}

Default is slideOutSlideIn, you can set it via initialization stage.

let chainView = ChainPageCollectionView(viewType: .normal, 
                                        childAnimationType: #yourchoice)

Layout

You can customize the layout objects by passing them via ChainPageCollectionView's designated initializer.

let chainView = ChainPageCollectionView(viewType: .normal, 
                                        parentColectionViewLayout: #yourlayout, 
                                        childCollectionViewLayout: #yourlayout)

ItemSize

You can use parentCollectionViewItemSize and childCollectionViewItemSize to set related layouts' itemSize.

Screen Ratio

The default behaviour of this view is that parent collection view takes 3/4 height of this view and child collection view takes the rest. You can set viewType to a customized ratio with type customParentHeight(#SomeInt, #SomeInt)

let chainView = ChainPageCollectionView(viewType: .customParentHeight(28, 12))

License

Expanding collection is released under the MIT license. See LICENSE for details.