Equal horizontal spacing UICollectionView, including insets - UICollectionViewFlowLayout? - ios

Question

I'm trying to create equal horizontal spacing between two UICollectionViewCell and between a UICollectionViewCell an the screen border. It should look like this.
I think it is possible to use UICollectionViewFlowLayout to adjust the width of every UICollectionViewCell, so they have equal spacings regardless of the phone's size. There should always only be 3 cells on each row.

Answer 1

First of all you should add constants for all parameters of UICollectionView to the controller:
let itemsPerRow = 3
let spaceBetweenItems: CGFloat = 20.0
let spaceBetweenLines: CGFloat = 40.0
let itemHeight: CGFloat = 50.0
You mentioned that item's width should be adjustable. You can calculate it with this function:
var itemWidth: CGFloat {
return (self.collectionView.frame.width - CGFloat(self.itemsPerRow + 1) * self.spaceBetweenItems) / CGFloat(self.itemsPerRow)
}
Of course you need to customise layout of your UICollectionView instance:
var collectionViewLayout: UICollectionViewFlowLayout {
let result = UICollectionViewFlowLayout()
result.itemSize = CGSize(width: self.itemWidth, height: self.itemHeight)
result.minimumInteritemSpacing = self.spaceBetweenItems
result.minimumLineSpacing = self.spaceBetweenLines
result.sectionInset = UIEdgeInsets(top: 0.0, left: self.spaceBetweenItems, bottom: 0.0, right: self.spaceBetweenItems)
result.scrollDirection = .vertical
return result
}
And in the function viewDidLoad or your controller you should call setupCollectionView(). Here is a code of this function:
func setupCollectionView() {
self.collectionView.frame = self.view.frame
self.collectionView.collectionViewLayout = self.collectionViewLayout
}
You will see something like this: