How to adjust height of UICollectionView to be the height of the content size of the UICollectionView?

Question

I would like the UICollectionView (The red one) to shrink to the height of the content size in this case UICollectionViewCells(the yellow ones) because there is a lot of emp

Answer 1

1) Set Fix Height of your CollectionView.

2) Create Outlet of this CollectionView Height Constant. Like :

IBOutlet NSLayoutConstraint *constHeight;

3) Add below method in your .m file:

- (void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];

    CGFloat height = collectionMenu.collectionViewLayout.collectionViewContentSize.height;
    constHeight.constant = height;
}

Answer 2

first of all calculate number of cells than multiply it with height of cell and then return height in this method

    collectionView.frame = CGRectMake (x,y,w,collectionView.collectionViewLayout.collectionViewContentSize.height); //objective c
    //[collectionView reloadData];
   collectionView.frame = CGRect(x: 0, y: 0, width: width, height: collectionView.collectionViewLayout.collectionViewContentSize.height) // swift

Answer 3

Get the height of the cell. Something like this

let cellHeight = cell.frame.height

Get the origin of the collection view

let cvOrigin = collectionView.frame.origin

Get the width of the collection view

let cvWidth = collectionView.bounds.width

Set the frame of the content view

collection.frame = CGRect(x: cvOrigin.x, y: cvOrigin.y, width: cvWidth, height: cellHeight )

Answer 4

If you set the height constraint of the collection view. Just observe the contentSize change in the viewDidLoad and update the constraint.

        self.contentSizeObservation = collectionView.observe(\.contentSize, options: [.initial, .new]) { [weak self] collectionView, change in
            guard let `self` = self else { return }
            guard self.collectionView.contentSize != .zero else { return }
            self.collectionViewHeightLayoutConstraint.constant = self.collectionView.contentSize.height
        }

Answer 5

In Swift 5 and Xcode 10.2.1

1. Fix Height of the CollectionView

2. Create Outlet of your CollectionViewHeight

   IBOutlet weak var myCollectionViewHeight: NSLayoutConstraint!
   

3. Use below code

   override func viewDidLayoutSubviews() {
       super.viewDidLayoutSubviews()
       let height = myCollectionView.collectionViewLayout.collectionViewContentSize.height
       myCollectionViewHeight.constant = height
       self.view.layoutIfNeeded()
   }
   

Answer 6

Do following.

1. first set height constrain for UICollectionView
2. here calendarBaseViewHeight is UICollectionView height Variable

3. call the function after reload the collection view

   func resizeCollectionViewSize(){  
          calendarBaseViewHeight.constant = collectionView.contentSize.height      
    }