UICollectionView spacing margins

Question

I have a UICollectionView which shows photos. I have created the collectionview using UICollectionViewFlowLayout. It works good but I would like to

Answer 1

Set the insetForSectionAt property of the UICollectionViewFlowLayout object attached to your UICollectionView

Make sure to add this protocol

UICollectionViewDelegateFlowLayout

Swift

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets (top: top, left: left, bottom: bottom, right: right)
    }

Objective - C

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsMake(top, left, bottom, right);
}

Answer 2

Using collectionViewFlowLayout.sectionInset or collectionView:layout:insetForSectionAtIndex: are correct.

However, if your collectionView has multiple sections and you want to add margin to the whole collectionView, I recommend to use the scrollView contentInset :

UIEdgeInsets collectionViewInsets = UIEdgeInsetsMake(50.0, 0.0, 30.0, 0.0);
self.collectionView.contentInset = collectionViewInsets;
self.collectionView.scrollIndicatorInsets = UIEdgeInsetsMake(collectionViewInsets.top, 0, collectionViewInsets.bottom, 0);

Answer 3

You can use the collectionView:layout:insetForSectionAtIndex: method for your UICollectionView or set the sectionInset property of the UICollectionViewFlowLayout object attached to your UICollectionView:

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsMake(top, left, bottom, right);
}

or

UICollectionViewFlowLayout *aFlowLayout = [[UICollectionViewFlowLayout alloc] init];
[aFlowLayout setSectionInset:UIEdgeInsetsMake(top, left, bottom, right)];

Updated for Swift 5

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
       return UIEdgeInsets(top: 25, left: 15, bottom: 0, right: 5)
    }

Answer 4

Swift 4

    let flow = collectionView.collectionViewLayout as! UICollectionViewFlowLayout 
    // If you create collectionView programmatically then just create this flow by UICollectionViewFlowLayout() and init a collectionView by this flow.

    let itemSpacing: CGFloat = 3
    let itemsInOneLine: CGFloat = 3
    flow.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)

    //collectionView.frame.width is the same as  UIScreen.main.bounds.size.width here.
    let width = UIScreen.main.bounds.size.width - itemSpacing * CGFloat(itemsInOneLine - 1) 
    flow.itemSize = CGSize(width: floor(width/itemsInOneLine), height: width/itemsInOneLine)
    flow.minimumInteritemSpacing = 3
    flow.minimumLineSpacing = itemSpacing

EDIT

XCode 11.4 and swift 5

let flow = collectionView.collectionViewLayout as! UICollectionViewFlowLayout

doesn't work. Use below works.

let flow = UICollectionViewFlowLayout()

and after configuration:

collectionView.collectionViewLayout = flow

And if you want to change to scrollDirction horizontally:

flow.scrollDirection = .horizontal

NOTE

If you set items in one lines isn't correctly, check if your collection view has paddings. That is:

let width = UIScreen.main.bounds.size.width - itemSpacing * CGFloat(itemsInOneLine - 1)

should be the collectionView width.

Answer 5

In swift 4 and autoLayout, you can use sectionInset like this:

let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .vertical
        layout.itemSize = CGSize(width: (view.frame.width-40)/2, height: (view.frame.width40)/2) // item size
        layout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10) // here you can add space to 4 side of item
        collectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: layout) // set layout to item
        collectionView?.register(ProductCategoryCell.self, forCellWithReuseIdentifier: cellIdentifier) // registerCell
        collectionView?.backgroundColor = .white // background color of UICollectionView
        view.addSubview(collectionView!) // add UICollectionView to view

Answer 6

To put space between CollectionItems use this

write this two Line in viewdidload

UICollectionViewFlowLayout *collectionViewLayout = (UICollectionViewFlowLayout*)self.collectionView.collectionViewLayout;
collectionViewLayout.sectionInset = UIEdgeInsetsMake(<CGFloat top>, <CGFloat left>, <CGFloat bottom>, <CGFloat right>)