Dynamic UICollectionView header size based on UILabel

Question

I\'ve read a bunch of posts on adding header to UICollectionView. In an iOS 7+ app in Swift, I\'m trying to add a header with a UILabel in it whose height should adjust base

Answer 1

In your cell add the following:

fileprivate static let font = UIFont(name: FontName, size: 16)
fileprivate static let insets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)

Adjust both fonts and insets accordignly.

Then add the following to your cell

   static func textHeight(_ text: String, width: CGFloat) -> CGFloat {
    let constrainedSize = CGSize(width: width - insets.left - insets.right, height: CGFloat.greatestFiniteMagnitude)
    let attributes = [ NSAttributedStringKey.font: font ]
    let options: NSStringDrawingOptions = [.usesFontLeading, .usesLineFragmentOrigin]
    let bounds = (text as NSString).boundingRect(with: constrainedSize, options: options, attributes: attributes as [NSAttributedStringKey : Any], context: nil)
    return ceil(bounds.height) + insets.top + insets.bottom
}

You can now use this function to calculate automatic height

  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
    let height = ManuallySelfSizingCell.textHeight("Your text", width: view.frame.width)
    return CGSize(width: view.frame.width, height: height + 16)
}