iOS Swift: How to check if UILabel is truncated? Calculate number of lines for UILabel

UILabelCountLines.swift

func countLabelLines(label: UILabel) -> Int {
    // Call self.layoutIfNeeded() if your view uses auto layout
    let myText = label.text! as NSString

    let rect = CGSize(width: label.bounds.width, height: CGFloat.greatestFiniteMagnitude)
    let labelSize = myText.boundingRect(with: rect, options: .usesLineFragmentOrigin, attributes: [NSAttributedStringKey.font: label.font], context: nil)

    return Int(ceil(CGFloat(labelSize.height) / label.font.lineHeight))
}

Thank you very much! You helped a lot) It works)

Code updated to Swift 5 and made as UILabel extension. Also 0 will be returned if the label doesn't have any text.

extension UILabel {
  func countLines() -> Int {
    guard let myText = self.text as NSString? else {
      return 0
    }
    // Call self.layoutIfNeeded() if your view uses auto layout
    let rect = CGSize(width: self.bounds.width, height: CGFloat.greatestFiniteMagnitude)
    let labelSize = myText.boundingRect(with: rect, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: self.font as Any], context: nil)
    return Int(ceil(CGFloat(labelSize.height) / self.font.lineHeight))
  }
}

Now you can perform something like:

class MyAwesomeViewController: UIViewController {
  @IBOutlet weak var myAwesomeLabel: UILabel!

  override func viewDidLoad() {
    if myAwesomeLabel.countLines() >= 2 {
      // Do some stuff
    }
  }
}

I have 2 lines UILabels but still this extension shows me 1 line

I have 3 lines UILabels but still this extension shows me 1 line

In order to work you must call it after func viewDidLayoutSubviews() was called.
It uses the label frame. In viewDidLoad this value is still not correct which leads to you getting incorrect values.