ios - Read More/Less with Swift 3

Question

I want to add "Read more" at the end of the paragraph. When I click on the "Read more" text, it should be expand and display "Less" at the end. The texts will be collapsed when click on "Less" text.

I find many sample work in google. But, I don't understand clearly and most projects are implemented with Objective-C. I also find it in youtube.
I would like know very sample code to implement this with Swift 3.
Can I implement without using any additional library?
Please help me.

Answer 1

• Create an outlet for height constraint of your messageLabel
• Set top layout of your "Read more" button to messageLabel

• On clicking "Read more" button increase height constraint constant, on clicking "Read less" decrease height constraint constant.

  @IBOutlet weak var btn: UIButton!
  
  @IBOutlet weak var lblHeight: NSLayoutConstraint!
  
  var isLabelAtMaxHeight = false
  
  @IBAction func btnAction(_ sender: Any) {
      if isLabelAtMaxHeight {
          btn.setTitle("Read more", for: .normal)
          isLabelAtMaxHeight = false
          lblHeight.constant = 70
      }
      else {
          btn.setTitle("Read less", for: .normal)
          isLabelAtMaxHeight = true
          lblHeight.constant = getLabelHeight(text: yourSummaryText, width: view.bounds.width, font: yourSummaryLabel.font)
      }
  }
  

Get height of a text

    func getLabelHeight(text: String, width: CGFloat, font: UIFont) -> CGFloat {
        let lbl = UILabel(frame: .zero)
        lbl.frame.size.width = width
        lbl.font = font
        lbl.numberOfLines = 0
        lbl.text = text
        lbl.sizeToFit()

        return lbl.frame.size.height
    }