How to set no spacing in UICollectionViewDelegateFlowLayout?

Question

I'm trying to do a UICollectionViewDelegateFlowLayout with 3 items to a row at a third of the screen width. For some reason it's adding spacing and not conforming to the square layout.

Here are the UICollectionViewDelegateFlowLayout functions.

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
     let yourWidth = (collectionView.bounds.width/3.0) - 2

     let yourHeight = yourWidth



        return CGSize(width: yourWidth, height: yourHeight)
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        //return UIEdgeInsets.zero
        return UIEdgeInsets(top: 0,left: 0,bottom: 0,right: 0);
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 1
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 1
    }

Please do not suggest adding a layout to a collection view in the viewDidLoad method. I tried that and it didn't work because it deletes my header.

(collectionView.bounds.width - 2) / 3.0 I think this is the formula to calculate 1/3 width with only 1 pixel spacing between cells — Aqeel Ahmad, Dec 27 '19 at 07:42

Celeste · Answer 1 · 2019-12-27T00:04:47.757

0

class VC : UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {



func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
 let yourWidth = (collectionView.frame.width - 4)/3
      // your minimumInteritemSpacing is 1, hence 4

 let yourHeight = yourWidth

    return CGSize(width: yourWidth, height: yourHeight)
}



}

You can also try:

 override func viewDidLoad() {
    super.viewDidLoad()

   let layout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout
    layout?.estimatedItemSize = .init()
    layout?.headerReferenceSize = .init()

 }

edited Dec 27 '19 at 00:04

answered Dec 26 '19 at 20:27

Celeste

1,519
6
19

the first doesn't work. is there more code to the second one? also if I use the second one that seems to delete my header. how can I keep the header while using the second one? – Nick Steen Dec 26 '19 at 23:46
How did you set the header size ? I edited my answer , you can add : layout?.headerReferenceSize = .init() – Celeste Dec 27 '19 at 00:04
I set the header size in storyboard. this still does not work after the edits. it just appears as the same size but at the top of the simulator. – Nick Steen Dec 27 '19 at 01:19

score 0 · Answer 2 · answered Dec 27 '19 at 05:36

You can try with following code:

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
     let marginsAndInsets = inset * 2 + collectionView.safeAreaInsets.left + collectionView.safeAreaInsets.right + minimumInteritemSpacing * CGFloat(cellsPerRow - 1)

        //set inset, minimumInteritemSpacing and cellsPerRow globally

        let itemSize = ((collectionView.bounds.size.width - marginsAndInsets) / CGFloat(cellsPerRow)).rounded(.down)

        return CGSize(width: itemSize, height: itemSize)
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        //return UIEdgeInsets.zero
        return UIEdgeInsets(top: 0,left: 0,bottom: 0,right: 0);
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 1
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 1
    }

How to set no spacing in UICollectionViewDelegateFlowLayout?

2 Answers2